Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

  • Review
  • Intervention

Authors

  • Arne Ohlsson,

    Corresponding author
    1. University of Toronto, Departments of Paediatrics, Obstetrics and Gynaecology and Institute of Health Policy, Management and Evaluation, Toronto, ON, Canada
    • Arne Ohlsson, Departments of Paediatrics, Obstetrics and Gynaecology and Institute of Health Policy, Management and Evaluation, University of Toronto, 600 University Avenue, Toronto, ON, M5G 1X5, Canada. aohlsson@mtsinai.on.ca.

    Search for more papers by this author
  • Sanjay M Aher

    1. Dr. Aher's Neocare Hospital, Neonatology, Nashik, Maharashtra, India
    Search for more papers by this author

Abstract

Background

Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia.

Objectives

To assess the effectiveness and safety of early initiation of EPO or darbepoetin (initiated before eight days after birth) in reducing red blood cell (RBC) transfusions in preterm and/or low birth weight infants.

Search methods

The Cochrane Library, MEDLINE, EMBASE, CINAHL, reference lists of identified trials and reviews, Pediatric Academic Societies Annual meetings 2000 to 2013 (Abstracts2ViewTM) and clinical trials registries (clinicaltrials.gov; controlled-trials.com; and who.int/ictrp) were searched in July 2013.

Selection criteria

Randomised or quasi-randomised controlled trials of early (< eight days of age) initiation of EPO treatment versus placebo or no intervention in preterm and/or low birth weight infants.

Data collection and analysis

The methods of the Neonatal Cochrane Review Group were used.

Main results

The updated review includes 27 studies enrolling 2209 infants. One study enrolling infants at a mean age of > eight days and one duplicate publication were excluded. One new study using darbepoetin was identified.

Early EPO reduced the risk of the 'use of one or more RBC transfusions' (typical risk ratio (RR) 0.79, 95% confidence interval (CI) 0.73 to 0.85; typical risk difference (RD) -0.14, 95% CI -0.18 to -0.10; I2 = 54% for both; number needed to treat to benefit (NNTB) 7, 95% CI 6 to 10; 16 studies, 1661 infants).

The total volume of RBCs transfused per infant was reduced (typical mean difference (MD) 7 mL/kg, 95% CI -12 to - 2; I2 = 63%; 7 studies, 581 infants). The number of RBC transfusions per infant was minimally reduced (typical MD -0.27, 95% CI -0.42 to -0.12; I2 = 64%; 13 studies, 951 infants). The number of donors to whom the infants were exposed was significantly reduced (MD-0.54, 95% CI -0.89 to -0.20; I2 = 0%; 3 studies, 254 infants).

There was a non-significant increase in the risk of stage ≥ 3 retinopathy of prematurity (ROP) with early EPO (typical RR 1.37, 95% CI 0.87 to 2.17; I2 = 0%; typical RD 0.03, 95% CI -0.01 to 0.06; I2 = 29%; 7 studies, 801 infants). A post hoc analysis including all studies that reported on ROP stage ≥ 3, regardless of the age of the infant when EPO treatment was started, showed a significantly increased typical RR of 1.48 (95% CI 1.02 to 2.13; P = 0.04; I2 = 0%) and typical RD of 0.03 (95% CI 0.00 to 0.06; P = 0.03; I2 = 50%; 10 studies, 1303 infants) with a number needed to treat to harm (NNTH) of 33 (95% CI 17 to infinity). In an Italian study in which the authors compared the use of early intravenous EPO with subcutaneous EPO the overall incidence of stage ≥ 3 was 15%, similar to the incidence of 17% in the study by Romagnoli and co-workers.

The rates for mortality and morbidities including intraventricular haemorrhage and necrotizing enterocolitis were not significantly changed by early EPO treatment. Neurodevelopmental outcomes at 18 to 22 months varied.

Authors' conclusions

Early administration of EPO reduces the use of RBC transfusions, the volume of RBCs transfused, and donor exposure after study entry. The small reductions are likely to be of limited clinical importance. Donor exposure is probably not avoided since all but one study included infants who had received RBC transfusions prior to trial entry. In this update there was no significant increase in the rate of ROP (stage ≥ 3) for studies that initiated EPO treatment at less than eight days of age. In a post hoc analysis including all studies that reported on ROP stage ≥ 3 regardless of age at initiation of treatment there was an increased risk of ROP. The rates for mortality and morbidities including intraventricular haemorrhage and necrotizing enterocolitis were not significantly changed by early EPO treatment. Neurodevelopmental outcomes at 18 to 22 months vary in the studies published to date. Ongoing research should deal with the issue of ROP and evaluate current clinical practice that will limit donor exposure. Due to the limited benefits and the possibly increased risk of ROP, administration of EPO is not recommended. Darbepoetin requires further study. The possible neuroprotective role of EPO in neonates will be reviewed in separate Cochrane reviews.

Plain language summary

Early erythropoietin for preventing red blood cell transfusion in preterm, low birth weight infants, or preterm infants with low birth weight

In newborn infants, the number of red blood cells in the circulation decreases after birth. In infants born before term this decrease is exaggerated by frequent withdrawal of blood, which may be necessary to monitor the infant's clinical condition. Therefore, infants born before term are likely to require transfusions of red blood cells. Low levels of erythropoietin (EPO), a substance in the blood that stimulates red blood cell production, in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia. EPO can be given 'early' (before the infant reaches eight days of age) in order to prevent or decrease the use of red blood cell transfusions. A total of 2209 infants born before term have been enrolled in 27 studies that used this approach. Early EPO treatment reduced the number of red blood cell transfusions and donor exposures following its use. However, the overall benefit of EPO may not be clinically important as many of these infants had been exposed to red blood cell transfusions prior to entry into the trials. Treatment with early EPO did not have any important effects on mortality or common complications of preterm birth with the exception that EPO may increase the risk for retinopathy of prematurity, a serious complication that can cause blindness in babies born before term. Based on our findings EPO is not recommended for routine use in preterm infants.

Background

Description of the condition

After birth, the haemoglobin concentration of newborn infants normally falls to minimal levels of 11 g/dL in term infants by eight to 12 weeks of age and 7.0 to 10.0 g/dL in preterm infants by six weeks of age (Stockman 1978). This process is called physiologic anaemia of infancy (Strauss 1986). In very low birth weight (VLBW) infants the hematocrit falls to approximately 24% in infants weighing 1.0 to 1.5 kg and 21% in infants weighing less than 1.0 kg at birth (Stockman 1986). In extremely low birth weight (ELBW) infants, this decline in hematocrit to levels below 7.0 to 10.0 g/dL is called anaemia of prematurity and is associated with clinical findings such as pallor, poor weight gain, decreased activity, tachypnoea, tachycardia and feeding problems that prompt red blood cell (RBC) transfusions. Repeated blood drawing, shortened RBC survival, rapid growth, and attenuated erythropoietin (EPO) response all contribute to anaemia of prematurity. To our knowledge the diagnostic accuracy of different clinical signs and laboratory findings has not been studied (Cohen 1998). It is still unknown how low hematocrit levels can fall before clinical signs of anaemia of prematurity occur and what the acceptable minimal hematocrit level is in infants requiring supplemental oxygen (Ohls 2002). A rational guide for transfusion therapy for all anaemic neonates, whether ventilated or not, is not available (Cohen 1998). Nevertheless, 'top-up' transfusions to treat low haemoglobin or low hematocrit levels are frequently used. As many as 80% of VLBW infants and 95% of ELBW infants receive blood transfusions during their hospitalizations (Widness 1996). A Cochrane review on 'Low versus high haemoglobin concentration threshold for blood transfusion for preventing morbidity and mortality in very low birth weight infants' concludes "The use of restrictive as compared to liberal haemoglobin thresholds in infants of very low birth weight results in modest reductions in exposure to transfusion and in haemoglobin levels. Restrictive practice does not appear to have a significant impact on death or major morbidities at first hospital discharge or at follow-up" (Whyte 2011).

Description of the intervention

The primary goal of EPO therapy is to reduce the number of transfusions. Most transfusions are given during the first three to four weeks of life. The larger or stable preterm infants who respond best to EPO receive few transfusions. ELBW infants, who are sick and have the greatest need for RBC transfusions shortly after birth, have not consistently responded to EPO. This suggests that EPO is a more effective erythropoietic stimulator in more mature neonates. ELBW neonates are more likely to need transfusions even if their erythropoiesis is stimulated by EPO (Kotto-Kome 2004). In addition, ELBW neonates have a smaller blood volume and the relatively larger phlebotomy volumes that are required during hospital stay often necessitate 'early' transfusions. In contrast 'late' transfusions are more often given because of anaemia of prematurity (Garcia 2002). Most preterm infants who require blood transfusions will receive their first transfusion in the first two weeks of life (Zipursky 2000). Reducing the number of RBC transfusions reduces the risk of transmission of viral infections and may reduce costs. Frequent RBC transfusions may be associated with retinopathy of prematurity (ROP) (Hesse 1997) and bronchopulmonary dysplasia (BPD).

Preterm infants need iron for erythropoiesis. As neonatal blood volume expands with rapid growth, infants produce large amounts of haemoglobin. Several studies have observed a decrease in serum ferritin concentration during EPO treatment, an indication of iron deficiency (Finch 1982). The use of higher, more effective doses of EPO might be expected to increase iron demand and the risk of iron deficiency. Iron supplementation during EPO treatment has been observed to reduce the risk of the development of iron deficiency (Shannon 1995a). The range of iron doses used in EPO treated infants is between 1 mg/kg/day to 10 mg/kg/day (Kotto-Kome 2004).

How the intervention might work

EPO, with the addition of iron, effectively stimulates erythropoiesis. Plasma EPO levels in neonates are lower than those of older children and adults. Brown and colleagues reported that at between two and 30 days of life the mean EPO concentration was 10 mIU/mL as compared to 15 mIU/mL in concurrently studied adults (Brown 1983). A low plasma EPO level is an important reason that nadir hematocrit values of preterm infants are lower than those of term infants (Dallman 1981; Stockman 1986). Low plasma EPO levels provide a rationale for the use of EPO in the prevention or treatment of anaemia of prematurity. Studies in newborn monkeys and sheep have demonstrated that neonates have a large volume of distribution and more rapid elimination of EPO, necessitating the use of higher doses than required for adults. A systematic review of EPO administration in VLBW infants noted a wide range of doses used, from 90 to 1400 IU/kg/week (Kotto-Kome 2004). Side effects following EPO use in adults include hypertension, bone pain, rash and rarely seizures. Only transient neutropenia has been reported in neonates (Ohls 2000).

Why it is important to do this review

The efficacy of EPO in anaemia of prematurity has been systematically reviewed (Vamvakas 2001; Garcia 2002; Kotto-Kome 2004). Vamvakas and co-workers concluded that there is extreme variation in the results of EPO studies and until this variation is better understood it is too early to recommend EPO as standard treatment for anaemia of prematurity (Vamvakas 2001). Garcia and co-workers concluded that administering EPO to VLBW neonates can result in a modest reduction in late erythrocyte transfusions and that this effect is dependent on the dose of EPO used (Garcia 2002). Kotto-Kome and co-workers concluded that if EPO is begun in the first week of life a moderate reduction can be expected in the proportion of VLBW neonates transfused. The reduction is less significant for early transfusion than for late transfusion (Kotto-Kome 2004).

EPO has been found to have important non-haematopoietic functions in the brain and other organs during development (Juul 2002). Administration of EPO could potentially have a neuroprotective effect in preterm infants, especially in perinatal asphyxia (Juul 2002, Dame 2001). This aspect of EPO use in neonates will be systematically reviewed separately (Yu 2010).

It is likely that additional studies of EPO in preterm or LBW infants have been published since the reviews noted above. We therefore performed a series of Cochrane reviews on the use of EPO in preterm infants, including 'Early erythropoietin (EPO) for preventing red blood cell transfusion in preterm or low birth weight infants' (starting in infants ≤ 7 days of age; < 8 days of age) versus placebo or no treatment (this review), 'Late EPO (starting in infants > 7 days of age; ≥ 8 days of age) versus placebo/no treatment' (Aher 2006a) and 'Early versus late EPO' (as per previous definitions) (Aher 2006b). These reviews were all updated in 2009 and 2012 (Aher 2012; Aher 2012a; Ohlsson 2012). The cut-off of ≤ 7 days of age for early and > 7 days for late treatment with EPO, although somewhat arbitrary, was chosen based on previously published meta-analyses (Garcia 2002; Kotto-Kome 2004) to allow us to compare the results between our reviews and previously published reviews.

This review concerns the early administration of EPO (starting in infants ≤ 7 days of age). The main rationale for such EPO therapy is to reduce exposure of neonates to red blood cell transfusion and its associated risks. Between 60% and 100% of preterm infants are transfused before three weeks of age (Shannon 1995a; Juul 1999; Zipursky 2000) and EPO administered during this period might decrease the need for RBC transfusions (Brown 1990; Kotto-Kome 2004). Several studies have concentrated on the effectiveness of administering EPO, beginning in the first week of life, in reducing or eliminating these 'early' transfusions. We conducted a systematic review to evaluate all available studies where EPO was begun during the first week of life to assess the effect on erythrocyte transfusions.

A slightly modified long-acting version of EPO, darbepoetin alfa (Darbe), has been introduced (Egrie 2001). Darepoetin was created by modifying five amino acids of the original EPO protein in order to generate two additional carbohydrate binding sites, thereby significantly increasing the circulating half-life and effectiveness. Compared to EPO, it has an approximate three-fold longer serum half-life, greater in vivo potency, and can be administered less frequently to obtain the same biological response. A single subcutaneous dose of darbepoetin alfa has been shown to accelerate erythropoiesis in preterm infants (Warwood 2005).

Objectives

Primary objective

To assess the effectiveness and safety of early initiation of EPO or darbepoetin (initiated before eight days after birth) in reducing red blood cell transfusions in preterm and/or low birth weight infants.

Secondary objectives

Subgroup analyses were performed within this review for low (≤ 500 IU/kg/week) and high (> 500 IU/kg/week) doses of EPO and the amount of iron supplementation: none, low (≤ 5 mg/kg/day) and high (> 5 mg/kg/day).

Methods

Criteria for considering studies for this review

Types of studies

Randomised or quasi-randomised controlled trials.

Types of participants

Preterm (< 37 weeks) and/or low birth weight (< 2500 g), neonates less than eight days of age.

Types of interventions

Early initiation of EPO (initiated before eight days of age, using any dose, route, or duration of treatment) versus placebo or no intervention.

For this update we included studies that used darbepoetin alfa, a novel erythropoiesis stimulating agent (Egrie 2001; Warwood 2005). We kept the analyses for EPO and darbepoetin alfa separate.

Types of outcome measures

Primary outcomes
  1. The proportion of infants exposed to one or more RBC transfusions

Secondary outcomes
  1. The total volume (mL/kg) of blood transfused per infant

  2. Number of transfusions per infant

  3. Number of donors to whom the infant was exposed

  4. Mortality during initial hospital stay (all causes of mortality)

  5. Retinopathy of prematurity (ROP) (any stage and stage ≥ 3)

  6. Proven sepsis (clinical symptoms, signs of sepsis and positive blood culture for bacteria or fungi)

  7. Necrotising enterocolitis (NEC) (Bell's stage II or more, or stage not reported)

  8. Intraventricular haemorrhage (IVH), all grades (we included in this group results from studies that did not define the grade) and grades III and IV

  9. Periventricular leukomalacia (PVL), cystic changes in the periventricular areas (note: for this updated review we included persisting increased echogenicity in this outcome)

  10. Length of hospital stay (days)

  11. Bronchopulmonary dysplasia (BPD) (supplementary oxygen at 28 days of age or at 36 weeks postmenstrual age (PMA) with or without compatible X-ray; we included an additional group in which the age at BPD was not stated)

  12. Sudden infant death after discharge

  13. Neutropenia

  14. Hypertension (not a pre-specified outcome)

  15. Long-term outcomes assessed at any age beyond one year of age by a validated cognitive; motor; language; or behavioural, school, social interaction, adaptation test

  16. Cerebral palsy

  17. Post hoc analysis: any side effects reported in the trials (it is not possible to predict every side effect that can occur with a certain intervention; however, it is important that 'new side effects' are reported)

Search methods for identification of studies

The standard search method of the Cochrane Neonatal Review Group was used.

Electronic searches

The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2006, Issue 1) was searched to identify relevant randomized and quasi-randomised controlled trials. MEDLINE was searched for relevant articles (from 1966 to November 2005) using the following MeSH terms or text words: (exp Erythropoietin/OR erythropoietin:.mp. OR rhuepo.mp.) AND (anaemia/OR exp anaemia, neonatal/) AND (blood transfusion/OR blood component transfusion/OR erythrocyte transfusion/) AND (infant, newborn/OR infant, low birth weight/OR infant, very low birth weight/OR infant, premature/OR exp Infant, Premature, Diseases) OR (neonate: OR prematur*: OR newborn:).mp. OR newborn infant [age limit]) AND (clinical trial.pt. OR Randomized Controlled Trials/OR (random: OR rct OR rcts OR blind OR blinded OR placebo:).mp. OR (review.pt. OR review, academic.pt.) AND human. EMBASE (from 1980 to November 2005) and CINAHL (1982 to November 2005) were searched using the following MeSH terms or text words: (Erythropoietin/OR erythropoietin: OR epo OR epogen OR epoetin: OR (rhuepo).mp. AND (anaemia/OR exp anaemia, neonatal/) AND (blood transfusion/OR exp blood component transfusion/OR erythrocytes/) AND exp Infant, Premature, Diseases/OR infant, newborn/OR infant, low birth weight/OR infant, very low birth weight/OR infant, premature/OR (neonate: OR newborn: OR prematur*:).mp. OR newborn infant [age limit]. No language restrictions were applied.

For this review update, the same search strategy was applied in July 2013.

Searching other resources

Manual searches of bibliographies and personal files were performed. No language restrictions were applied. Abstracts published from the Pediatric Academic Societies' Meetings and the European Society of Pediatric Research Meetings (published in Pediatric Research) were handsearched from 1980 to April 2005.

For this update in 2013 the Pediatric Academic Societies' Annual meetings from 2000 to 2013 (Abstracts2ViewTM) were searched electronically in July 2013.

Clinical trials registries were searched in July 2013 for ongoing or recently completed trials (clinicaltrials.gov; controlled-trials.com; and who.int/ictrp).

Data collection and analysis

The standard review methods of the Cochrane Neonatal Review Group were used to assess the methodological quality of studies. We used the methods described in the Cochrane Handbook for Systematic Reviews of Interventions Version 5.1 (Higgins 2011).

Selection of studies

Two review authors assessed all abstracts and published studies identified as potentially relevant by the literature search for inclusion in the review. For studies identified as abstracts, we contacted the primary authors, when possible, to obtain further information if the full publication was not available.

Data extraction and management

For the original version of this review, both review authors extracted data separately on to a data abstraction form. The information was compared and differences were resolved by consensus. One review author (AO) entered data into RevMan and the other (SA) cross-checked the printout against his own data abstraction forms and errors were corrected. The updates in 2009 and 2012 were conducted by one review author (AO).

This update in 2013 was conducted by both authors (AO, SA).

Assessment of risk of bias in included studies

For the original review, the quality of the included trials was evaluated independently by the review authors using the following criteria: blinding of randomization; blinding of intervention; blinding of outcome measure assessment; and completeness of follow-up. There were three potential answers to these questions: yes, no, cannot tell.

For the 2012 and 2013 updated reviews the following areas were assessed and entered into the table Characteristics of included studies under the heading risk of bias.

Selection bias

(random sequence generation and allocation concealment)

For each included study, we categorized the risk of selection bias as follows.

Random sequence generation

Low risk - adequate (any truly random process e.g. random number table; computer random number generator)

High risk - inadequate (any non-random process e.g. odd or even date of birth; hospital or clinic record number)

Unclear risk - no or unclear information provided

Allocation concealment

Low risk - adequate (e.g. telephone or central randomization; consecutively numbered sealed opaque envelopes)

High risk - inadequate (open random allocation; unsealed or non-opaque envelopes, alternation; date of birth)

Unclear risk - no or unclear information provided

Performance bias

For each included study, we categorized the methods used to blind study personnel from knowledge of which intervention a participant received. As our study population consisted of neonates they would all be blinded to the study intervention.

Low risk - adequate for personnel (a placebo that could not be distinguished from the active drug was used in the control group).

High risk - inadequate, personnel aware of group assignment.

Unclear risk - no or unclear information provided.

Detection bias

For each included study, we categorized the methods used to blind outcome assessors from knowledge of which intervention a participant received. As our study population consisted of neonates they would all be blinded to the study intervention. Blinding was assessed separately for different outcomes or classes of outcomes. We categorized the methods used with regards to detection bias as follows.

Low risk - adequate, follow-up was performed with assessors blinded to group.

High risk - inadequate, assessors at follow-up were aware of group assignment.

Unclear risk - no or unclear information provided.

Attrition bias

For each included study and for each outcome, we described the completeness of data including attrition and exclusions from the analysis. We noted whether attrition and exclusions were reported, the numbers included in the analysis at each stage (compared with the total number of randomized participants), reasons for attrition or exclusion where reported, and whether missing data were balanced across groups or were related to outcomes. Where sufficient information was reported or supplied by the trial authors, we re-included missing data in the analyses. We categorized the methods with respect to the risk attrition bias as follows.

Low risk - adequate (< 10% missing data).

High risk - inadequate (> 10% missing data).

Unclear risk - no or unclear information provided.

Reporting bias

For each included study, we described how we investigated the risk of selective outcome reporting bias and what we found. We assessed the methods as follows.

Low risk - adequate (where it is clear that all of the study's pre-specified outcomes and all expected outcomes of interest to the review have been reported).

High risk - inadequate (where not all the study's pre-specified outcomes have been reported; one or more reported primary outcomes were not pre-specified; outcomes of interest are reported incompletely and so cannot be used; study fails to include results of a key outcome that would have been expected to have been reported).

Unclear risk - no or unclear information provided (the study protocol was not available).

Other bias

For each included study, we described any important concerns we had about other possible sources of bias (for example whether there was a potential source of bias related to the specific study design or whether the trial was stopped early due to some data-dependent process). We assessed whether each study was free of other problems that could put it at risk of bias as follows.

Low risk - no concerns of other bias raised.

High risk - concerns raised about multiple looks at the data with the results made known to the investigators, difference in number of patients enrolled in abstract and final publications of the paper.

Unclear - concerns raised about potential sources of bias that could not be verified by contacting the authors.

If needed, we planned to explore the impact of the level of bias through undertaking sensitivity analyses.

For the original review, independent quality assessments were conducted by the two review authors (SMA, AO), who were not blinded to authors, institution or journal of publication. The updates in 2009 and the update in 2012 were conducted by one review author (AO). The update in 2013 was conducted by both authors (AO, SMA).

Measures of treatment effect

Statistical analyses were performed using Review Manager software (RevMan 2011). Categorical data were analyzed using risk ratio (RR), risk difference (RD) and the number needed to treat to benefit (NNTB) or number needed to treat to harm (NNTH). Continuous data were analyzed using mean difference (MD). The 95% confidence interval (CI) was reported on all estimates.

Unit of analysis issues

In all studies the individual infant was the unit of analysis.

Dealing with missing data

We approached several authors for additional data or clarification of data.

Assessment of heterogeneity

Heterogeneity tests including the I2 statistic were performed to assess the appropriateness of pooling the data (Higgins 2003). We used the following criteria for describing the percentages of heterogeneity: < 25% no heterogeneity, > 25% to 49% low heterogeneity, > 50% to 74% moderate heterogeneity and ≥ 75% high heterogeneity.

Assessment of reporting biases

We conducted a funnel plot for the primary outcome in Comparison 1. Erythropoietin versus placebo or no treatment, outcome 1.1 Use of one or more RBC transfusions (low and high dose of EPO); for Comparison1. Erythropoietin versus placebo or no treatment, outcome 1.9 ROP (stage ≥ 3); and for Comparison 1. Erythropoietin versus placebo or no treatment, outcome 1.29 ROP (stage ≥ 3) in infants treated with EPO before or after eight days of age.

Data synthesis

Meta-analysis was performed using RevMan 5.2, supplied by The Cochrane Collaboration (RevMan 2011). For estimates of typical RR and RD we used the Mantel-Haenszel method. For measured quantities we used the inverse variance method. If the RD was statistically significant we calculated the NNTB or NNTH. All meta-analyses were done using the fixed-effect model.

Subgroup analysis and investigation of heterogeneity

Subgroup analyses were performed for low (≤ 500 IU/kg/week) and high (> 500 IU/kg/week) doses of EPO and low (≤ 5 mg/kg/day) and high (> 5 mg/kg/day) doses of supplemental iron by any route (co-intervention). Any amount of iron given intravenously (iv) was classified as high-dose iron.

Sensitivity analysis

Two post hoc analyses were conducted to try and explain the between-study heterogeneity for the primary outcome 'use of one or more RBC transfusions'. In the first post hoc analysis, we divided the studies into two groups: 'high quality studies' and 'studies of uncertain quality'. In the second post hoc analysis, we analyzed the results for the four studies in which most of the neonatal intensive care units (NICU) enrolling patients used satellite units of RBCs for transfusion. In a third post hoc analysis we included the results for ROP ≥ 3 for all available studies regardless of the age of the infant at initiation of treatment with EPO.

Results

Description of studies

Results of the search

Two new studies for inclusion were identified in this 2013 update (Yasmeen 2012; Ohls 2013). Twenty-seven studies randomising 2209 infants were included. In the 2012 update a second publication (Haiden 2006a) of a previously included study was identified (Haiden 2005). The studies were performed in 20 countries (Austria, Bangladesh, Belgium, Chile, China, France, Germany, Greece, Italy, Iran, Mexico, New Zealand, Poland, Singapore, South Africa, Switzerland, Turkey, the Netherlands, the UK, and the US). In the study by Ohls 2013 102 infants were randomized to darbepoetin alfa, EPO or sham injection. This was the first study assessing the effectiveness and safety of darbepoetin. We reported separately on two comparisons: darbepoetin versus no treatment and EPO versus no treatment.

In this 2013 update three studies were excluded (Romagnoli 2000; Bierer 2006; Saeidi 2012). The study by Romagnoli 2000 was moved to the late EPO review. However, the results for ROP stage ≥ 3 are reported in a secondary (post hoc) analysis that includes all studies that reported on that outcome regardless of at what age the EPO treatment was initiated. Two other late EPO studies were included for this post hoc analysis (Shannon 1995; Al-Kharfy 1996). These three studies do not contribute data to any other analyses in this early EPO review. These studies are clearly indicated below under 'Included studies' and in the table 'Characteristics of included studies'. To be able to include the studies in the post hoc analysis they had to be listed as included studies and cannot be listed as excluded studies. These studies are not included in the total number of studies or infants included in this review. The study by Bierer 2006 was excluded as it represents a duplicate publication of the Ohls 2001A study. Another newly identified early EPO randomized controlled trial (RCT) was excluded as both groups received EPO (Saeidi 2012). We do report on the high incidence of stage ≥ 3 ROP in both groups of that study.

All included studies fulfilled our inclusion criteria of a gestational age < 37 weeks and/or birth weight < 2500 g. Inclusion of infants in the studies was based on either postmenstrual age (PMA) or birth weight or a combination. The highest cut-off for birth weight was 1800 g and the highest cut-off for PMA was 35 weeks (Chang 1998). The lowest cut-off for birthweight was 401 g (Ohls 2001A). Most studies used an upper cut-off for birth weight of 1500 g and a PMA of 32 to 33 weeks.

EPO was administered subcutaneously or intravenously or in a combination of intravenous followed by subcutaneous when intravenous access was no longer available. The dose ranged from 70 IU/kg/week (Obladen 1991) to 2100 IU/kg/week (Haiden 2005). The duration of EPO treatment ranged from two weeks (Ohls 1995; Ohls 1997) to nine weeks (Maier 2002) or to discharge from hospital (several studies). The study by Fauchère 2008 was designed to ascertain whether administration of high-dose EPO (3000 IU rhEPO/kg body weight) given intravenously three to six, 12 to 18, and 36 to 42 hours after birth would have a neuroprotective effect. In that study no infant was treated at a later time with EPO.

Many different EPO preparations were used: EPREX 2000, Santa-Farma-Gurel, Istanbul (Arif 2005); Eprex, Cilag, Italy (Carnielli 1998); Cilag A.G., Zug, Switzerland (Soubasi 1993; Soubasi 1995; Soubasi 2000); Eprex 4000, Cilag de Mexico SA de CV (Lima-Rogel 1998); Eprex, Janssen-Cilag, Auckland, New Zealand (Meyer 2003); Eprex, Cilag comp (Khatami 2008); Recormon, Boehringer (Lauterbach 1995; Avent 2002); NeoRecormon, F Hoffman-La Roche, Basel, Switzerland (Maier 2002); Epoetin beta, Boehringer-Mannheim, GmbH, Germany (Obladen 1991; Maier 1994); Kirin Brewery, Co, Ltd, Japan (Chang 1998); unnamed product (Carnielli 1992; Ohls 1995; Ohls 1997; Yeo 2001; Ohls 2001A; Ohls 2001B; He 2008; Yasmeen 2012; Ohls 2013); Erypo, Janssen-Cilag Pharmaceuticals, Vienna, Austria (Meister 1997; Haiden 2005); Eritropoyetina del Laboraorio Andromaco (Salvado 2000); and Epoietin beta, Roche, Basel, Switzerland (Fauchère 2008).

Previous donor exposure was stated as an exclusion criterion in one study (Arif 2005). Maier 1994 included 28 infants (23%) in the EPO group and 17 (14%) in the control group who had received RBC transfusions prior to study entry. Maier 2002 reported that 24 (32%) of the infants in the early EPO group and 22 (31%) in the control group were exposed to donor blood before they entered the study. Ohls 2013 reported that 17% of infants were transfused before study entry. The authors of the remaining studies reported their specific exclusion criteria but did not list prior transfusion as an exclusion criterion. We assumed that infants who had received prior RBC transfusions were included.

Details for the transfusion guidelines are reported in the additional tables (Table 1: Transfusion guidelines). As noted in the table, transfusion guidelines were based on various hematocrit (Hct) or haemoglobin (Hgb) levels. In addition, researchers used many other criteria such as need for assisted ventilation, supplemental oxygen, age of the infant, weight gain, clinical condition, and physiological or biochemical signs thought to be associated with anaemia. In a few studies we were unable to categorize the different guidelines that could be meaningfully used for secondary analyses.

Table 1. Transfusion guidelines
  1. BPD: bronchopulmonary dysplasia
    CPAP: continuous positive airway pressure
    Hct: hematocrit
    Hgb: haemoglobin
    hrs: hours

    MAP: mean airway pressure

    RR: respiratory rate

ReferenceIndications
Arif 2005Infants with Hgb concentrations < 7 gm/dL and with a reticulocyte count lower than < 100,000/µL or Hgb concentrations < 8 gm/dL having bradycardia, tachypnoea or apnea, or who were not able to gain weight despite adequate calorie intake were chosen as candidates for blood transfusion
Avent 2002Infants received blood transfusions if they met the following criteria:
1. Hgb of 10 gm/dL and one of the following: (i) an oxygen requirement greater than 30%; (ii) less than 1250 g body weight
2. Hgb < 8 gm/dL and one of the following: (i) three or more episodes of apnea (respiration absent for 20 seconds) or bradycardia (heart rate of < 100 beats/min) in a 24-hr period not due to other causes and not responsive to methylxanthine treatment; (ii) fractional inspired oxygen concentrations increasing by >10 % per week; (iii) tachycardia (> 170 beats/min) or tachypnoea (> 70 breaths/min) sustained over a 24-hr period associated with acute cardiac decompression
Carnielli 1992Infants were transfused during the first week of life with packed erythrocytes if the Hct level was < 42% or 36%, depending on whether or not the patient was receiving supplemental oxygen. After the first week of life, indications for transfusions were Hct < 36% for oxygen-dependent patients and 32% if breathing room air. Anaemia was the only indication for giving packed erythrocytes to all infants
Carnielli 1998Infants received transfusions of packed cells during the first week of life if their peripheral Hct (heel stick) was < 42% or 36%, depending on whether or not the patient was receiving supplemental oxygen.
After the first week of life, indications for transfusion were Hct < 36% for oxygen dependent patients and 32% if in room air. Hct concentrations for red blood cell transfusions for blood obtained from venepuncture or arterial samples were 4% lower than the above mentioned values (38% and 32% for oxygen dependent and non-oxygen dependent patients in the first week and 0.32 and 0.28 thereafter). All infants received dedicated units of red blood cells
Chang 1998Not stated whether transfusion guidelines were in place or not
Fauchère 2008Transfusion guidelines not provided
Haiden 2005Infants were transfused at Hct < 20%
a) if asymptomatic with reticulocytes < 100,000/µL
Infants were transfused at Hct < 30%
a) if receiving < 35% supplemental hood oxygen
b) if on CPAP or mechanical ventilation with mean air way pressure < 6 cm H2O
c) if significant apnea and bradycardia are noted (> 9 episodes in 12 hrs or 2 episodes in 24 hrs requiring bag and mask ventilation) while receiving therapeutic doses of methylxanthines
d) if heart rate > 180 beats/min or respiratory rate > 80 breaths /min persists for 24 hrs
e) if weight gain < 10 gm/day is observed over 4 days while receiving > 100 kcal/kg/day
f) if undergoing surgery
Transfuse for Hct < 35%
a) if receiving > 35% supplemental hood oxygen
b) if intubated on CPAP or mechanical ventilation with mean airway pressure > 6-8 cm H2O
Do not transfuse:
a) to replace blood removed for laboratory tests alone
b) for low Hct alone
He 2008Transfusion guidelines not reported in the English abstract of this study. We have requested the full text in Chinese from the authors
Khatami 2008"Guidelines for red-cell transfusions were based on the relatively strict existing policy in the nursery which was used to administer transfusions during the study period"
Lauterbach 1995Transfusion was given when the Hct level reached 28% and if clinical symptoms of tachypnoea, tachycardia, bradycardia were present at a Hct of 0.32
Lima-Rogel 1998According to criteria published by Klaus and Fanaroff
Maier 1994Infants who were receiving ventilation or who were less than two weeks old and had signs of anaemia were given transfusions if their Hct fell below 40%, their Hgb concentration fell below 14 gm/dL (8.7 mmol/L), or blood samples totaling at least 9 mL/kg had been obtained from them since their previous transfusion.
Spontaneously breathing infants, more than two weeks old, whose fraction of inspired oxygen was < 0.40 were given transfusions if they had signs of anaemia and their Hct fell below 32% and their Hgb concentration below 11 gm/dL (6.8 mmol/L); if they had signs of anaemia, the corresponding cut-off values were 27% and 9 gm/dL (5.6 mmol/L)
Maier 2002Infants with artificial ventilation or > 40% of inspired oxygen were not transfused unless Hct dropped below 0.40.
Spontaneously breathing infants were not transfused unless Hct dropped below 0.35 during the first 2 weeks of life, 0.30 during the 3rd to 4th weeks, and 0.25 thereafter. Transfusion was allowed when life threatening anaemia or hypovolaemia was assumed by the treating neonatologist, or surgery was planned. Twelve of the 14 centres used satellite pack of the original red cell pack to reduce donor exposure
Meister 1997Infants more than two weeks old who have been breathing spontaneously and whose fraction of inspired oxygen was less than 0.40 were given transfusions if they had signs of anaemia and their Hct fell below 11 gm/dL (6.8 mmol/L); if they had no signs of anaemia, the corresponding cut-off values were 27% and 9 gm/dL (5.6 mmol/L)
Meyer 2003Indications for transfusions were:
Hct of 36-40% and critically ill with: requirement for oxygen > 45% via CPAP; ventilation (mean airway pressure > 10 cm H2O); severe sepsis; active bleeding
Hct of 31-35% and: requirement for oxygen (up to 45%) via CPAP; ventilation (mean airway pressure 7-10 cm H2O)
Hct of 21-30% and: gain less than 10 gm/day averaged over one week; experience either at least 10-12 apneic or bradycardic episodes in 12 hours or two or more such episodes requiring bag and mask ventilation within a 24 hour period, not due to other causes and not responsive to methylxanthine treatment; have a sustained tachycardia (> 170 beats/min) or tachypnoea (> 70/min) per 24 hours and not attributable to other causes; develop cardiac decompensation secondary to a clinically apparent patent ductus arteriosus; positive pressure ventilation on low settings (mean airway pressure < 7 cm H2O) or nasal CPAP; those requiring surgery
Hct 20% and reticulocyte count < 100 x 109/L
Obladen 1991Indications for transfusion of packed red cells:
If venous Hct < 42%, Hgb < 14 gm/dL or > 9 mL/kg blood sampled since last transfusion transfuse if infant is ventilated or requires FiO2 > 0.40
If age 1-2 weeks and symptoms of anaemia (apneic spells, distended abdomen, failure to thrive) transfuse if venous Hct is < 36%, Hgb < 12 gm/dL or > 9 mL/kg blood sampled since last transfusion
If age 3-5 weeks and symptoms of anaemia (apneic spells, distended abdomen, failure to thrive) transfuse if venous Hct is < 30%, Hgb < 10 gm/dL or > 9 mL/kg blood sampled since last transfusion
If no symptoms of anaemia transfuse at any age if venous Hct is < 27%, Hgb < 9 g/dL
Ohls 1995Transfusions were given during the first three week of life if the Hct was < 33%, and if the infant had one or more symptoms thought to be due strictly to anaemia. Symptoms were defined as tachycardia (heart rate > 160 beats/min, calculated as the average of all heart rates recorded by the bedside nurse during the preceding 24-hour period), an increasing oxygen requirement (an increase in fraction of inspired oxygen of > 0.20 during a 24-hour period), "lethargy" as assessed by the primary caregiver, or an increase in the number of episodes of bradycardia requiring stimulation to increase the heart rate from less than 60 beats/min (an increase of such episodes by 3 or more per day. Infants in both groups whose Hct were > 33% and yet whose phlebotomy losses exceeded 10 mL/kg body weight received an infusion of 5% albumin, administered in aliquots of not less than 10 mL/kg. Infants were not given transfusions if they were free of symptoms, even if the Hct fell to < 33%.
Ohls 1997Transfusions were administered in both groups according to standardized transfusion criteria: for infants requiring mechanical ventilation, transfusions were given if the Hct fell below 33%. For infants not receiving ventilatory support, transfusions were given if the Hct fell below 28%, and the infant was experiencing symptoms. Symptoms were defined as tachycardia (heart rate > 160 beats/min, calculated as the average of all heart rates recorded by the bedside nurse over the preceding 24-hour period), an increasing oxygen requirement (an increase in fraction of inspired oxygen of > 0.20 over a 24-hour period, or an elevated lactate level (>2.5 mmol/L). In some instances a new donor would be used each day for the newborn intensive care unit (university of Florida), and in other instances a unit would be dedicated to a single infant for the life of the unit (University of New Mexico and University of Utah).
Ohls 2001AIf Hct ≤ 35%/Hgb ≤ 11 gm/dL transfuse infants requiring moderate or significant mechanical ventilation (MAP > 8 cm H2O and FiO2 > 0.4)
If Hct ≤ 30%/Hgb ≤ 10 gm/dL transfuse infants requiring minimal respiratory support (any mechanical ventilation or endotracheal/nasal CPAP >6 cm H2O and FiO2 ≤ 0.4)
If Hct ≤ 25%/Hgb ≤ 8 gm/dL transfuse infants not requiring mechanical ventilation but who are on supplemental O2 or CPAP with an FiO2 ≤ 0.4 and in whom 1 or more of the following is present: 24 hrs of tachycardia (180 beats/min) or tachypnoea (>80 breaths/min)
an increased oxygen requirement from the previous 48 hrs, defined as 4-fold increase in nasal canula flow (i.e., 0.25 L/min to 1 L/min) or an increase in nasal CPAP 20% from the previous 48 hrs (i.e., 5 cm to 6 cm H2O)
weight gain < 10 gm/kg/day over the previous 4 days while receiving 100 kcal/kg/day an increase in the episodes of apnea and bradycardia (> 9 episodes in a 24-hr period or 2 episodes in 24 hrs requiring bag-mask ventilation) while receiving therapeutic doses of methylxanthines, undergoing surgery
If Hct ≤ 25%/Hgb ≤ 7 gm/dL transfuse asymptomatic infants with and an absolute reticulocyte count <100,000 cells/µL
Ohls 2001BSee Ohls 2001 A
Ohls 2013

The PRBC volume transfused was based on Hct/Hgb, Respiratory Support and/or Symptoms

If Hct ≤ 30/Hgb ≤ 10 and the infant required moderate/significant ventilation (MAP >8 cm H2O and FiO2 > 0.4) the PRBC volume to be transfused was 15–20 mL/kg
If Hct ≤ 25/Hgb ≤ 8 and the infant required minimal respiratory support (any mechanical ventilation with FiO2 < 0.4, or CPAP >6 cm H2O and FiO2 >0.4) the PRBC volume to be transfused was 20 mL/kg
If Hct was ≤ 20/Hgb ≤ 7 and the infant required supplemental oxygen or CPAP with an FiO2 < 0.4, and at least 1 of the following:
• ≥ 24 h of tachycardia (heart rate >180) or tachypnoea (RR >60)
• a doubling of the oxygen requirement from the previous 48 h
• lactate ≥ 2.5 mEq/L or an acute metabolic acidosis (pH,7.20)
• weight gain <10 g/kg/d over the previous 4 d while receiving ≥ 120 kcal/kg/d
• undergoing surgery within 24 h

the PRBC volume to be transfused was 20 mL/kg

If Hct ≤18/Hgb ≤ 6 and the infant was asymptomatic and the absolute reticulocyte count (ARC) was <100,000 cells/µL the PRC volume to be transfused was 20 mL/kg

Salvado 2000Preterm infants with Hct < 20%
Preterm infants with Hct < 30% when presenting with frequent apneas, or tachycardia >180 beats/min, or requiring surgery
Soubasi 1993Neonates, who were well, were transfused if their Hct was < 25% combined with signs referable to their anaemia, such as poor weight gain, persistent episodes of bradycardia or tachypnoea, and apnea. Neonates with severe respiratory disease (BPD), particularly those requiring oxygen and/or ventilator support, received transfusions to maintain their Hct level at > 40%
Soubasi 1995Infants who were receiving mechanical ventilation or who were less than 2-weeks-old were given transfusion if their Hct fell below 40%. Spontaneously breathing infants more than 2-weeks-old whose fraction of inspired oxygen was less than 0.35 were given transfusion if they had signs of anaemia and their Hct fell below 30%; if they had no signs of anaemia, transfusion was given if Hct fell below 0.25. Growing, asymptomatic infants were transfused if Hct fell below 20%. Signs of anaemia included; tachycardia, (>170 beats/min) or tachypnoea (> 70 per min) sustained over a 24-hr period or associated with acute cardiac decompression; recurrent apnea (respirations absent for 20 seconds) or bradycardia (heart rate < 100 beats/min) in a 24-hr period not due to other causes and not responsive to methylxanthine treatment; an increased in fractional oxygen requirement by 20% or more over a 24-hr period; or weight gain of < 10 gm/day averaged over a 1-week period while on adequate caloric intake.
Soubasi 2000Neonates were transfused when Hct was < 20%, if they were asymptomatic, or < 30% if they were receiving O2 < 0.35 and/or unexplained breathing disorders combined with signs referable to their anaemia, such as poor weight gain, episodes of persistent bradycardia or tachycardia
Yeo 2001Infants who were receiving mechanical ventilation or who were less than 2-weeks-old were given transfusion if their Hct fell below 40%. Spontaneously breathing infant more than 2-weeks-old whose fraction of inspired oxygen was less than 35% were given transfusion if they had signs of anaemia and their Hct fell below 30%; if they had no signs of anaemia, transfusion was given if Hct fell below 25%. Growing, asymptomatic infants were transfused if Hct fell below 20%. Signs of anaemia included; tachycardia, (>170 beats/min) or tachypnoea (> 70 per min) sustained over a 24-hr period or associated with acute cardiac decompression; recurrent apnea (respirations absent for 20 seconds) or bradycardia (heart rate < 100 beats/min) in a 24-hr period not due to other causes and not responsive to methylxanthine treatment; an increased in fractional oxygen requirement by 20% or more over a 24-hr period; or weight gain of < 10 gm/day averaged over a 1-week period while on adequate caloric intake.
Yasmeen 2012After discharge from hospital any patient with Hgb level of ≤ 7 gm/dl was readmitted in the hospital and managed with packed red cell transfusion

Transfusion guidelines were reported to be in place in all but two studies (Chang 1998; Fauchère 2008). We have not been able to obtain information from the trial by He 2008 and Lima-Rogel 1998 referred to the third Spanish edition of 'Care of the high-risk neonate' by Klaus and Fanaroff for the guidelines they adhered to (Klaus 1987). We were not able to locate that book but in the third English edition of the book we could not find transfusion guidelines for preterm infants (Klaus 1986).

In the study by Carnielli et al (Carnielli 1998), all infants received dedicated units of RBCs. In one of the studies by Ohls et al (Ohls 1997), it was stated that "In some instances a new donor would be used each day for the newborn intensive care unit (University of Florida) and in other instances a unit would be dedicated to a single infant for the life of the unit (University of New Mexico and University of Utah)". These two studies did not report on our primary outcome of 'use of one or more RBC transfusions'. In the study by Maier et al (Maier 2002), 12 of the 14 centres used satellite packs of the original red cell pack to reduce donor exposure. In the two studies by Ohls et al (Ohls 2001A; Ohls 2001B) it was noted that "Whenever possible designated donor units that were capable of providing at least four transfusions were assigned to each infant (available in six of the eight participating centres)". In a secondary (post hoc) analysis, we combined the results of these three studies. In Ohls 2013 each infant was assigned a matched, leuko-reduced, citrate-phosphate-dextrose adenine anticoagulant-preserved donor unit, made available in a sterile docking device capable of 50 mL aliquots of packed red blood cells (PRBCs) with ≥ four transfusions per unit, and a shelf life of 28 days.

Iron was administered in all studies but one (Fauchère 2008). We are awaiting information from the trial by He 2008. In most studies both the EPO and the control groups received iron but often the dose was lower in the control groups. In two studies (Carnielli 1992; Carnielli 1998), the infants in the control groups did not receive iron. In one study the use of iron was not stated in the abstract (He 2008).

Included studies

For details see the table Characteristics of included studies.

Al-Kharfy 1996: this study belongs to the late EPO review (for details see that review) and only the outcome of ROP stage ≥ 3 was included in a secondary (post hoc) analysis (Analysis 1.29).

Arif 2005 was a single-centre study performed in Istanbul, Turkey.

  • Objective: to determine whether EPO would prevent anaemia of prematurity and reduce the need for transfusion.

  • Population: preterm infants < 33 weeks gestational age (GA), birth weight < 1500 g, seven days old, not having had a previous blood transfusion.

  • Intervention: the EPO group received EPO 200 IU/kg sc from the seventh day of life and continued twice weekly (low dose) for six weeks. Placebo was not given to the control group. Both groups received iron (3 to 5 mg/kg per day orally) (low dose).

  • Outcomes assessed: use of one or more RBC transfusions, mortality, necrotising enterocolitis (NEC), ROP, bronchopulmonary dysplasia (BPD), neutropenia, side effects.

Avent 2002 was a two-centre study performed in South Africa.

  • Objective: to evaluate the effectiveness of early treatment with EPO (both high and low dose) in comparison with conventional treatment with packed RBC transfusions in the management of anaemia of prematurity in a country with limited resources.

  • Population: preterm infants < seven days of age, in room air or requiring up to 30% oxygen at study entry, with birth weight between 900 and 1500 g. Infants were stratified by weight < 1250 g and > 1250 g.

  • Intervention: one group received EPO 400 IU/kg sc three times a week (high dose), a second group received EPO 250 IU/kg sc three times a week (high dose). All infants received a therapeutic dose of 6 mg/kg (high dose) elemental iron orally every day and it was increased to 8 to 10 mg/kg (high-dose iron) if the hypochromic cells became 20% or more of the total cell population.

  • Outcomes assessed: use of one or more RBC transfusions, total volume (mL/kg) of blood transfused per infant, number of blood transfusions per infant, mortality and sepsis.

Carnielli 1992 was a single-centre study performed in Italy.

  • Objective: to determine whether early administration of a high dose of rHuEPO and iron to premature infants would be well tolerated and would reduce the need for blood transfusions.

  • Population: preterm infants with birth weight ≤ 1750 g and a GA ≤ 32 weeks, two days old.

  • Intervention: the EPO group received EPO 400 IU, three times weekly (high dose) iv or sc and iron 20 mg/kg once a week iv (high-dose iron) from second day of life until discharge. The control group did not receive either EPO or iron.

  • Outcome assessed: number and volume of transfusions, number of donor exposures, mortality during hospital stay, neutropenia and hospital stay in days.

Carnielli 1998 was a single-centre study performed in Italy.

  • Objective: to determine whether iron supplementation would enhance erythropoiesis in preterm infants treated with EPO.

  • Population: birth weight ≤ 1750 g and gestational age ≤ 32 weeks, two days old.

  • Intervention: the EPO + iron group received 400 IU/kg EPO three times a week (high dose) and 20 mg/kg/week of iv iron (high dose). The EPO + no iron group received EPO 400 IU/kg three times a week (high dose) without iron (no iron); infants in the control group received either no treatment or placebo.

  • Outcomes assessed: number of donor exposures, BPD, IVH, sepsis, ROP, days on ventilator, days of oxygen, days in hospital, days to regain birthweight, and weight gain from birth to eight weeks.

Chang 1998 was a single-centre study performed in China.

  • Objective: to assess the efficacy and the optimum dose of EPO on the anaemia of prematurity.

  • Population: infants with GA ≤ 35 weeks, birth weight ≤ 1800 g, age one day, and no rhesus (Rh) or ABO (blood group) incompatibility.

  • Intervention: infants in EPO group one received EPO 150 IU/kg three times a week for six weeks (low dose). Infants in EPO group two received EPO 250 IU/kg three times a week for six weeks (high dose) and infants in the control group (group three) received no EPO treatment. Infants in all three treatment groups received oral iron 20 mg/kg/day (high dose) from day seven after birth.

  • Outcomes assessed: use of one or more RBC transfusions, hypertension and side effects.

Fauchère 2008 was a single-centre study performed in Switzerland.

  • Objective: to investigate whether administration of high-dose EPO to very preterm infants shortly after birth and subsequently during the first two days was safe in terms of short-term outcomes.

  • Population: preterm infants with GA 24 0/7 to 31 6/7 weeks.

  • Intervention: infants in EPO group received 3000 IU rhEpo/kg iv three to six, 12 to 18, and 36 to 42 hours after birth. The placebo group received an equal volume of normal saline. Iron was not administered.

  • Outcomes assessed: mortality, IVH (all grades and grades III to IV), persisting periventricular echodensity (included in the analysis for periventricular leukomalacia (PVL)), ROP (all stages and stages 3 to 4), sepsis, NEC (stage not reported), BPD (36 weeks PMA), side effects.

Haiden 2005 was a multi-centre study performed at NICUs of the Department of Pediatrics, University of Vienna, Austria.

  • Objective: the aim of the study was to evaluate the effect of EPO therapy on platelet reactivity and thrombopoiesis in ELBW infants.

  • Population: preterm infants with BW ≤ 800 g and GA ≤ 32 weeks, < 8 days old.

  • Intervention: the EPO group received 300 IU/kg/day of EPO iv (as long as iv access was available), or 700 IU/kg three times per week (2100 IU/kg/week, high dose) and iron dextran 1.5 mg/kg/day iv or iron polymerase complex 9 mg/kg/day orally (high dose).

  • Outcomes assessed: use of one or more RBC transfusions, number of donors, mortality, NEC, PVL, IVH (grade I to II), IVH (grade III to IV), hospital stay, BPD (age not stated), ROP (stage I to II), ROP (stage III to IV).

He 2008 was a single-centre study performed in the Department of Neonatology, Zhangzhou Municipal Hospital, Zhangzhou, Fujian, China.

  • Objective: the aim of the study was to evaluate the effect of early EPO therapy on neurobehavioural development in preterm infants.

  • Population: preterm infants, seven days old.

  • Intervention: the EPO group received 250 IU/kg/day three times weekly iv for four weeks (750 IU/kg/week, high dose). The use of iron was not stated.

  • Outcomes assessed: Neonatal Behavioral Neurological Assessment at 40 weeks PMA and Gesell Developmental Schedule at six and 12 months after birth.

Khatami 2008 was a single-centre study performed at Ghaem Medical Center in Tehran, Iran.

  • Objective: the aim of the study was to evaluate whether EPO therapy would decrease the need for RBC transfusions and prevent anaemia of prematurity.

  • Population: preterm infants with BW > 1000 g but < 1750 g and GA > 28 weeks but < 34 weeks, and were between 48 and 96 hours old at the time of entering the study.

  • Intervention: the EPO group received 500 IU/kg/day of EPO sc twice weekly (1000 IU/kg/week, high dose) and iron (ferrous sulphate) 3 mg/kg/day enterally (low dose).

  • Outcomes assessed: number of RBC transfusions per patient, weight gain, hospital stay.

Lauterbach 1995 was a single-centre study conducted in Poland.

  • Objective: to evaluate the role of EPO in the treatment of anaemia of prematurity.

  • Population: preterm infants with GA < 35 weeks and birth weight ≤ 1500 g, seven days old.

  • Interventions: infants in EPO group I received EPO 100 IU/kg twice a week between days seven and 37 (low dose), and infants in EPO group II received 400 IU/kg twice weekly (high dose) during the same time period; the control group received no treatment or placebo. Both EPO groups and the control group received 10 mg/kg/week of iron iv (high dose).

  • Outcomes assessed: total volume (mL/kg) of blood transfused between days seven and 37.

Lima-Rogel 1998 was a single-centre study performed in Mexico.

  • Objective: to determine the efficacy of EPO in VLBW newborns less than 72 hours of age.

  • Population: infants with birth weight between 750 and 1500 g, < 72 hours old.

  • Intervention: infants in the EPO group received EPO 150 IU/kg/day (high dose) during the first six weeks and infants in the control group received placebo. Both groups received iron 4 mg/kg/day (low dose).

  • Outcomes assessed: number of transfusions per group, sepsis, NEC, IVH and BPD.

Maier 1994 was a multi-centre trial conducted in 12 centres in six European countries (Germany, Switzerland, UK, Belgium, the Netherlands, France).

  • Objective: to determine whether EPO would prevent anaemia and reduce the need for transfusion in infants with VLBW.

  • Population: infants with birth weights 750 to 1499 g, and three days old.

  • Intervention: the EPO group received 250 IU of EPO/kg im three times per week (750 IU/kg/week, high dose). The treatment continued until day 40 to 42 for total of 17 doses. Infants in the control group did not receive placebo but adhesive tape was placed on both thighs, which remained there until next visit. Oral iron 2 mg/kg/day was started on day 14 in all infants (low dose).

  • Outcomes assessed: use of one or more RBC transfusions, number of transfusions per infant, mortality, ROP, sepsis, NEC, IVH all grades, neutropenia, hypertension, side effects, weight gain and costs.

Maier 2002 was a multi-centre trial conducted in 14 centres in four European countries (Germany, Switzerland, France, Belgium).

  • Objective: to investigate whether EPO reduced the need for transfusion in ELBW infants and to determine the optimal time for treatment.

  • Population: infants with birth weight between 500 and 999 g, three to five days old.

  • Intervention: the EPO group received EPO 250 IU/kg, iv or sc three time a week (high dose) starting on day three to five of life, for nine weeks. The control group received sham injections. Enteral iron 3 mg/kg was given to all infants from days three to five (low dose) and was increased at days 12 to 14 to 6 mg/kg/day (high dose) and to 9 mg/kg/day (high dose) at days 24 to 26 of life.

  • Outcomes assessed: use of one or more RBC transfusions, number of donors the infant was exposed to, number of transfusions per infant, mortality during hospital stay, NEC, IVH, PVL, ROP, BPD, growth, days in oxygen, days in NICU, and days in hospital.

Meister 1997 was a single-centre trial conducted in Austria.

  • Objective: to evaluate the effect of EPO on circulating haematopoietic progenitor cells in anaemic premature infants.

  • Population: preterm infants with birth weights of 750 to 1499 g, at an age of five to 10 days.

  • Intervention: the EPO group received EPO 300 IU/kg sc three times a week (high dose) for four weeks. The control group did not receive the drug or placebo. Oral iron administration was started with a dose of 6 mg/kg/day (high dose) and increased after two weeks to 8 mg/kg/day (high dose). The control group received iron alone.

  • Outcomes assessed: cumulative volume of blood transfused/kg.

Meyer 2003 was a single-centre trial conducted in New Zealand.

  • Objective: to comprehensively identify preterm infants likely to require blood transfusion and to investigate the effectiveness of EPO in this high-risk subgroup.

  • Population: preterm infants with gestation < 33 weeks and birth weight < 1700 g, at an age of 48 hours.

  • Intervention: infants in the treatment group received EPO 1200 IU/kg/week sc in three divided doses (high dose) until three weeks of age and then the dose was reduced to 600 IU/kg/week until 34 weeks corrected GA, or for a minimum of three weeks. Infants in the control group received sham treatment. Both groups received elemental iron. Twenty-one infants in the control group received sham treatment to avoid subcutaneous injection. Iron at a dose of 6 mg/kg/day (high dose) was given to the EPO group once they had attained a postnatal age of two weeks and were receiving at least 50% energy intake orally. Those in the control group received 2 mg/kg/day iron (low dose) from the same age in a more dilute preparation so that an equivalent volume was given.

  • Outcomes assessed: use of one or more RBC transfusions and number of donors the infant was exposed to.

Obladen 1991 was a multi-centre study conducted at five centres in three European countries (Germany (FRG), Germany (GDR), UK).

  • Objective: to investigate whether treatment with EPO reduced the anaemia of prematurity and thus the need for transfusion by one third in preterm infants.

  • Population: preterm infants with GA 28 to 32 completed weeks, three days old.

  • Intervention: the EPO group received EPO 30 IU/kg (low dose) every third day from the fourth to 25th day of life. The control group did not receive study drug or placebo. Iron treatment 2 mg/kg (low dose) orally was started on day 14 if there was no feeding intolerance.

  • Outcomes assessed: use of one or more RBC transfusions, total volume of blood transfused per infant, mortality, chronic lung disease, IVH, NEC, BPD and hypertension.

Ohls 1995 was a single-centre trial conducted in the USA.

  • Objective: to determine whether administering EPO to ill VLBW infants, beginning on the first or second day of life, would reduce blood transfusions and be cost-effective.

  • Population: infants less than 48 hours of age with birth weight 750 and 1500 g and GA > 27 weeks.

  • Intervention: the EPO group received EPO 200 IU/kg/day (high dose) iv for 14 consecutive days. The control group received similar volume of 0.9% saline solution in similar fashion as placebo. Infants in both groups received iron 2 mg/kg/day (low dose) orally when they were taking 70 mL/kg per day enterally, which was increased to 6 mg/kg per day (high dose) when the infants were receiving more than 100 mL/kg per day of feeds.

  • Outcomes assessed: use of one or more RBC transfusions, total volume of blood transfused per infant, number of transfusions per infant, neutropenia, thrombocytopenia, neutrophilia, NEC and IVH.

Ohls 1997 was a multi-centre trial conducted in the USA.

  • Objective: to evaluate the effect of EPO on the transfusion requirements of preterm infants weighing 750 g or less.

  • Population: infants with birth weight 750 g or less and 72 hours of age or younger.

  • Intervention: the EPO group received EPO 200 IU/kg/day (high dose) iv, for 14 consecutive days. The control group received placebo as an equivalent volume of diluent in similar fashion. All infants received 1 mg/kg/day iron dextran in total parenteral nutrition (TPN) solution during treatment period (high dose).

  • Outcomes assessed: total volume of blood transfused per infant, number of transfusions per infant, mortality, sepsis, IVH, BPD and ROP.

Ohls 2001A was a multi-centre trial conducted in the USA.

  • Objective: to evaluate the effects of early EPO therapy on the transfusion requirements of preterm infants below 1000 g.

  • Population: infants with birth weight 401 to 1000 g, GA < 32 weeks and between 24 and 96 hours of age at the time of study entry.

  • Intervention: the EPO group received 400 IU/kg EPO three times weekly (high dose) iv or sc when iv access was not available. The placebo or control group received sham sc injections when iv access was not available. Treatment was continued until discharge, transfer, death or 35 completed weeks corrected gestational age. EPO treated infants received a weekly iv infusion of 5 mg/kg iron dextran (high dose) until they had an enteral intake of 60 mL/kg/day. Placebo or control infants received 1 mg/kg iron dextran (high dose) once a week, administered in a similar manner. Once infants in both groups had an enteral intake of 60 mg/kg/day they were given iron at a dose of 3 mg/kg/day (low dose). The dose was gradually increased to 6 mg/kg/day (high dose) depending on enteral intake.

  • Outcomes assessed: use of one or more RBC transfusions, mean number of erythrocyte transfusions per infant, number of donors to whom the infant was exposed, total volume of blood transfused per infant, late onset sepsis, mortality, chronic lung disease, ROP, severe IVH, NEC > Bell's stage II, BPD, neutropenia and hypertension. In a follow-up study of the 72 EPO treated and 70 placebo control infants surviving to discharge follow-up data at 18 to 22 months' corrected age were collected on 51 EPO -treated infants (71%) and 51 placebo controls (73%). The outcomes assessed were growth, psychomotor development, re-hospitalisation and transfusions.

Ohls 2001B was a multi-centre trial conducted in the USA.

  • Objective: to evaluate the effects of early EPO therapy on the transfusion requirements of preterm infants below 1250 g.

  • Population: infants with birth weight between 1001 g to 1250 g, GA < 32 weeks and between 24 and 96 hours of age at the time of study entry.

  • Intervention: the EPO group received 400 IU/kg EPO three times weekly (high dose) iv or sc when iv access was not available. The placebo control group received sham sc injections when iv access was not available. Treatment was continued until discharge, transfer, death or 35 completed weeks corrected GA. EPO treated infants received a weekly iv infusion of 5 mg/kg iron dextran (high dose) until they had an enteral intake of 60 mL/kg/day. Placebo control infants received 1 mg/kg iron dextran (high dose) once a week, administered in a similar manner. Once infants in both groups had enteral intake of 60 mg/kg/day they were given iron at a dose of 3 mg/kg/day (low dose). The dose was gradually increased to 6 mg/kg/day (high dose) depending on enteral intake.

  • Outcomes assessed: use one or more RBC transfusions, mean number of erythrocyte transfusions per infant, number of donors to whom the infant was exposed, total volume of blood transfused per infant, late onset sepsis, mortality, chronic lung disease, ROP, severe IVH, NEC > Bell's stage II, BPD, neutropenia and hypertension.

Ohls 2013 was a multi-centre study conducted in the USA.

  • Objective: to assess whether infants would respond to darbepoetin by reducing transfusion needs compared with no treatment, with less frequent dosing than erythropoietin.

  • Population: preterm infants 500 to 1250 g birth weight and < 48 hours of age.

  • Intervention: the darbepoetin group received 10 µg/kg, one time per week sc. The EPO group received 400 U/kg, three times per week sc. The control group received sham dosing. The injections continued through 35 weeks’ PMA. All infants (regardless of treatment arm) received supplemental iron, folate (50 mg per day oral), and vitamin E (15 IU per day oral). Iron dextran 3 mg/kg once a week was added to parenteral nutrition while infants were receiving 60 mL/kg per day enteral feedings. Oral iron 3 mg/kg per day was started when feedings were ≥ 60mL/kg per day, and increased to 6 mg/kg per day when feedings reached 120 mL/kg per day (high dose).

  • Outcomes assessed: use of one or more RBC transfusions, total volume (mL/kg) of blood transfused per infant, number of blood transfusions per infant, number of donors the infant was exposed to, mortality during initial hospital stay, ROP all stages and stages ≥ 3, late onset sepsis, NEC stage > 2, IVH grade ≥ 3, PVL, length of hospital stay, BPD (oxygen dependency at 36 weeks PMA), neutropenia and hypertension. Cognitive scores on Bayley Scales of Infant Development (BSID-III) and cerebral palsy (mild) at 18 to 22 months were reported in abstract form in 81 infants out of the original 102 infants enrolled.

Romagnoli 2000: this study belongs to the late EPO review but is included for the outcome of ROP stage > 3 regardless of when EPO treatment was initiated (Secondary analysis).

Salvado 2000 was a single-centre trial conducted in Chile.

  • Objective: to assess the benefits of early EPO administration to reduce the requirement of blood transfusion in VLBW infants.

  • Population: newborn infants with birth weight under 1500 g. Treatment started before 12 days of age (mean age EPO group 7.75 days, control group 7.96 days).

  • Intervention: the EPO group received EPO 200 IU/kg sc three times a week (high dose) during four weeks. The control group received a similar volume of isotonic saline solution in similar fashion. All infants received oral iron at a dose of 3 mg/kg/day (low dose).

  • Outcomes assessed: number of transfusions per infant, sepsis, IVH and days on ventilator.

Shannon 1995: this study belongs to the late EPO review, but is included for the outcome of ROP stage > 3 regardless of when EPO treatment was initiated (Secondary analysis).

Soubasi 1993 was a single-centre study conducted in Greece.

  • Objective: to assess whether EPO treatment is safe and reduces the need for transfusion.

  • Population: infants with GA ≤ 31 weeks, birth weight ≤ 1500 g, age one to seven days, no history of haemolytic disease and clinically stable.

  • Intervention: the EPO group received 150 IU/kg/dose of EPO twice a week (low dose) during four weeks. The control group received no placebo. From the 15th day of life iron was started at 3 mg/kg/day (low dose) in all infants.

  • Outcomes assessed: use of one or more RBC transfusions, number of transfusions per infant, mortality, sepsis, neutropenia, weight gain, hospital stay.

Soubasi 1995 was a single-centre study conducted in Greece.

  • Objective: follow-up of VLBW infants after EPO treatment.

  • Population: infants with GA ≤ 31 weeks, birth weight ≤ 1500 g, age one to seven days, no history of haemolytic disease and clinically stable.

  • Intervention: the EPO 300 group received EPO 150 IU/kg twice weekly (low dose) and the EPO 750 group received EPO 250 IU/kg three times a week (high dose). The control group did not receive any study drug or placebo. All infants received oral elemental iron, 3 mg/kg per day from day 15 of life (low dose).

  • Outcomes assessed: use of one or more RBC transfusions, number of blood transfusions per infant, mortality, follow-up to one year of age, weight gain and hospital stay.

Soubasi 2000 was a single-centre trial conducted in Greece.

  • Objective: to investigate the effect of EPO on oxygen affinity and adequate oxygen delivery to the tissues of stable preterm infants.

  • Population: infants with GA ≤ 31 weeks and birth weight ≤ 1300 g with clinical stability at the time of entry. Although the authors did not state the age at entry, we assumed the age to be seven days from a graph (figure 6) in the publication.

  • Intervention: the EPO group received 200 IU/kg every alternate day (high dose) sc. The control group did not receive EPO or placebo. The infants received oral iron at a dose of 12 mg/kg/day (high dose) in the EPO group and 4 mg/kg/day (low dose) in the control group.

  • Outcomes assessed: use of one or more RBC transfusions and number of transfusions per infant.

Yasmeen 2012 was a single-centre study conducted in Dhaka, Bangladesh.

  • Objective: to investigate the effect of short-term administration of EPO with iron and folic acid in prevention of anaemia of prematurity and reduction in the number of transfusions in preterm VLBW infants.

  • Population: infants with GA < 35 weeks, birth weight < 1500 g and age < 7 days.

  • Intervention: the EPO group received 200 IU/kg three times/week (high dose) sc. The control group did not receive EPO or placebo. All infants received oral iron at a dose of 6 mg/kg/day (high dose) and 0.5 mg of folic acid every alternate day up to 12 weeks of life. Both iron and folic acid administration started from day 14 of life or as soon as enteral feeding was initiated after day 14.

  • Outcomes assessed: mortality.

Yeo 2001 was a single-centre study conducted in Singapore.

  • Objective: to study the efficacy, safety and cost-effectiveness of EPO in reducing transfusion needs in VLBW infants.

  • Population: VLBW infants with GA ≤ 33 weeks, age five days.

  • Intervention: the EPO group received EPO 250 IU/kg/dose sc three times a week (high dose) from day five to day 40. Infants in the control group did not receive a placebo. Infants in both groups received elemental iron, 3 mg/kg/day (low dose) orally from day 10 and increased to 6 mg/kg/day (high dose) when full feeds were well tolerated.

  • Outcomes assessed: use one or more RBC transfusions, mean number of erythrocyte transfusions per infant, total volume of blood transfused per infant, mortality, ROP, sepsis, NEC, BPD, hypertension, BPD and costs.

Excluded studies

Nineteen studies were excluded (see table Characteristics of excluded studies).

Risk of bias in included studies

There was a report of proper random sequence generation in eight studies (Soubasi 1993; Soubasi 1995; Meister 1997; Soubasi 2000; Meyer 2003; Arif 2005; Fauchère 2008; Ohls 2013). The allocation to study groups was interpreted by us as concealed in 14 studies (Obladen 1991; Soubasi 1993; Maier 1994; Ohls 1997; Romagnoli 2000; Salvado 2000; Ohls 2001A; Ohls 2001B; Maier 2002; Meyer 2003; Haiden 2005; Fauchère 2008; Khatami 2008; Ohls 2013). Placebo or sham injections were used in 12 studies (Soubasi 1993; Maier 1994; Ohls 1995; Ohls 1997; Lima-Rogel 1998; Salvado 2000; Ohls 2001A; Ohls 2001B; Maier 2002; Meyer 2003; Fauchère 2008; Ohls 2013). Sample sizes were generally small and ranging from 19 (Lauterbach 1995) to 292 (Arif 2005) infants enrolled. Seven studies enrolled 100 infants or more. No study was reported according to the CONSORT statement (Begg 1996). There was complete follow-up in all studies.

Effects of interventions

Erythropoietin versus placebo or no treatment (Comparison 1)

Primary outcomes
Use of one or more red blood cell transfusions (low (< 500 IU/kg/week) and high (> 500 IU/kg/week) dose of EPO) (Outcome 1.1)

Figure 1

Figure 1.

Forest plot of comparison: 1 Erythropoietin versus placebo or no treatment, outcome: 1.1 Use of one or more red blood cell transfusions (low and high dose of EPO).

A total of 16 studies enrolling 1661 infants reported on the use of one or more RBC transfusions. Early EPO significantly reduced the proportion of infants who received one or more RBC transfusions (typical risk ratio (RR) 0.79, 95% confidence interval (CI) 0.73 to 0.85; typical risk difference (RD) -0.14, 95% CI -0.18 to -0.10; NNTB 7, 95% CI 6 to 10). There was moderate heterogeneity for this outcome (RR: I2 = 54%; RD: I2 = 54%).

Further analyses were conducted by including studies that used a high dose of EPO (> 500 U/kg/week) or a low dose of EPO (≤ 500 U/kg/week).

Use of one or more red blood cell transfusions (high dose of EPO (> 500 U/kg/week)) (Outcome 1.2)

A total of 14 studies enrolling 1228 patients testing a high dose of EPO reported on this outcome. A high dose of EPO significantly reduced the proportion of infants who received one or more RBC transfusions (typical RR 0.79, 95% CI 0.73 to 0.85; typical RD -0.15, 95% CI -0.19 to -0.10; NNTB 7, 95% CI 5 to 10). There was moderate heterogeneity for this outcome (RR: I2 = 57%; RD: I2 = 56%).

A subgroup analysis for a high dose of EPO in combination with a high dose of iron (Outcome table 1.2.1) was conducted. A total of 11 studies enrolling 863 infants reported on this outcome. A high dose of EPO with a high dose of iron significantly reduced the proportion of infants who received one or more RBC transfusions (typical RR 0.84, 95% CI 0.77 to 0.92; typical RD -0.11, 95% CI -0.16 to -0.05; NNTB 9, 95% CI 6 to 20). There was low or no heterogeneity for this outcome (RR: I2 = 32%; RD: I2 = 22%).

A total of three studies enrolling 365 infants testing a high dose of EPO and a low dose of iron (Outcome table 1.2.2) reported on this outcome. A high dose of EPO and a low dose of iron significantly reduced the proportion of infants who received one or more RBC transfusions (typical RR 0.66, 95% CI 0.55 to 0.80; typical RD -0.23, 95% CI -0.33 to -0.14; NNTB 4, 95% CI 3 to 7). There was high heterogeneity for this outcome for both RR and RD (I2 = 75%).

Use of one or more red blood cell transfusions (low dose of EPO (< 500 U/kg/week)) (Outcome 1.3)

A total of four studies including 484 patients testing a low dose of EPO (Outcome table 1.3) reported on this outcome. A low dose of EPO did demonstrate a significant reduction in the proportion of infants who received one or more RBC transfusions (typical RR 0.77, 95% CI 0.65 to 0.91; typical RD -0.13, 95% CI -0.22 to -0.05; NNTB 8, 95% CI 5 to 20). There was low and moderate heterogeneity for this outcome (RR: I2 = 47%; RD: I2 = 55%).

Subgroup analysis for a low dose of EPO in combination with a high dose of iron (Outcome table 1.3.1) was conducted. Two studies enrolling 322 infants reported on this outcome. In one of these studies there were no outcomes in either group. The significant RR was 0.75 (95% CI 0.61 to 0.93); the test for heterogeneity not applicable. The significant RD was -0.14 (95% CI -0.24 to -0.04). There was high heterogeneity for RD (I2 = 81%). The NNTB was 7 (95% CI 4 to 25).

Two studies enrolling 162 infants tested the effectiveness of a low dose of EPO in combination with a low dose of iron (Outcome table 1.3.2) and reported on this outcome. A low dose of EPO in combination with a low dose of iron did not significantly reduce the proportion of infants who received one or more RBC transfusions (typical RR 0.80, 95% CI 0.60 to 1.07; typical RD -0.12, 95% CI -0.26 to 0.03). There was moderate heterogeneity (I2 = 70%) for RR and low heterogeneity for RD (I2 = 48%).

Only one study included a group that received no iron (Carnielli 1998); however this study did not report on the primary outcome of interest 'use of one or more RBC transfusions'. In the study by Fauchère 2008 neither group received iron and this study did not report on the primary outcome of interest 'use of one or more RBC transfusions'.

Secondary outcomes
The total volume (mL/kg) of red blood cells transfused per infant (Outcome 1.4)

A total of seven studies enrolling 581 infants reported on the total volume of RBCs transfused per infant. The significant typical mean difference (MD) was a reduction of 6.8 mL/kg of blood transfused per infant (95% CI -11.5 to - 2.1). There was moderate heterogeneity for this outcome (I2 = 63%).

Carnielli 1998 reported on the mean volume of blood (mL/kg) transfused for the three groups: EPO + iron 16.7 (95% CI 4.9 to 28.6); EPO only 20.1 (95% CI 6.2 to 34.2) and the control group 44.4 (95% CI 29.0 to 59.7) (EPO versus control P = 0.028; EPO + iron versus control P = 0.009) (P values according to authors).

Lauterbach 1995 reported that infants treated with 800 IU of EPO/kg/week required a statistically significantly lower volume (mL/kg) of packed erythrocytes in comparison to untreated infants both between days seven and 37 of life (18.6 mL versus 46.8 mL) and between day seven of life and the day of discharge (35.8 mL versus 94.2 mL) (P < 0.04 for both comparisons).

Maier 2002 reported on the mean (SD) volume of blood transfused as mL/kg/day: early EPO group 0.7 (1.2) and control group 1.1 (1.2) (P value not provided). Meister 1997 reported on the median (first and third quartile) volume of blood transfused as mL/kg/day: EPO group 0 (0 to 0.47) and the control group 0.86 (0.5 to 1.1).

Number of red blood cell transfusions per infant (Outcome 1.5)

The results from 13 studies enrolling 951 infants reported on the number of RBC transfusions per infant. The significant typical MD for number of RBC transfusions per infant was -0.27 (95% CI -0.42 to -0.12). There was moderate heterogeneity for this outcome ( I2 = 64%).

Carnielli 1998 reported on the mean number of RBC transfusions for the three groups: EPO + iron 1.0 (95% CI 0.28 to 1.18); EPO only 1.3 (95% CI 0.54 to 2.06) and the control group 2.9 (95% CI 1.84 to 3.88) (control versus EPO P = 0.065; control versus EPO + iron P = 0.035) (P values according to the authors).

Avent 2002 reported the median and range of number of transfusions across three groups: low dose EPO group 0 (0 to 1), high dose EPO 0 (0 to 2) and control group 0 (0 to 4) (P = 0.03 across the three groups). Haiden 2005 reported on the number of transfusions: EPO group 2 (0 to 15), control group 4.5 (0 to 12) (not statistically significant according to the authors).

Number of donors to whom the infant was exposed (Outcome 1.6)
Number of donors the infant was exposed to among all randomized infants (Outcome 1.6.1)

Three studies enrolling 254 infants reported on this outcome as means and SDs. The significant typical MD for the number of donors to whom the infant was exposed was -0.54 (95% CI -0.89 to -0.20). There was no heterogeneity for this outcome (I2 = 0%).

Number of donors the infant was exposed to among infants who were transfused (Outcome 1.6.2)

Two studies enrolling 290 infants reported on this outcome. The non-significant typical MD for the number of donors the infant was exposed to among infants who were transfused was 0.05 (95% CI -0.33 to 0.42). There was moderate heterogeneity for this outcome (I2 = 63%).

Carnielli 1992 reported that the number of donor exposures ranged from zero to five in the EPO group and zero to six in the control group (P value not provided). Haiden 2005 reported on this outcome in a similar fashion: EPO group number of donors 1 (0 to 10), control group 3 (0 to 5) (not statistically significant according to the authors).

Mortality during initial hospital stay (all causes of mortality) (Outcome 1.7)

A total of 16 studies enrolling 1656 infants reported on this outcome. Mortality was not significantly altered by the use of EPO (typical RR 0.91, 95% CI 0.68 to 1.22; typical RD -0.01, 95% CI -0.04 to 0.02). There was no heterogeneity for this outcome (RR and RD: I2 = 0%).

Retinopathy of prematurity (all stages or stage not stated by authors) (Outcome 1.8)

A total of 8 studies enrolling 982 infants reported on retinopathy of prematurity (ROP). We obtained unpublished data from the study by Maier (Maier 2002) on the highest grade of ROP recorded during the study among examined survivors. There was no significant difference in the incidence of ROP (all stages or stage not stated by authors) (typical RR 0.99, 95% CI 0.81 to 1.21; typical RD -0.00, 95% CI -0.05 to 0.05). There was no heterogeneity for this outcome (RR and RD: I2 = 0%).

Retinopathy of prematurity (stage > 3) (Outcome 1.9)

Figure 2

Figure 2.

Forest plot of comparison: 1 Erythropoietin versus placebo or no treatment, outcome: 1.9 Retinopathy of prematurity (stage ≥ 3).

A total of seven studies enrolling 801 infants reported on severe ROP (stage ≥ 3). There was no significant difference in ROP (stage ≥ 3) between the groups (typical RR 1.37, 94% CI 0.87 to 2.17; typical RD 0.03, 95% CI -0.01 to 0.06). There was no heterogeneity for this outcome for RR (I2 = 0%) and there was low heterogeneity for RD (I2 = 29%). Ohls 1997 reported no differences in ROP (stage ≥ 3) rates between groups (data not provided).

Costa 2013 compared intravenous to subcutaneous early EPO in 100 infants. The study was excluded as there was no untreated control group. The overall incidence of ROP in the two groups was 15%, close to the 17% incidence in the Romagnoli 2000 study that was moved to the late EPO review as the treatment with EPO was initiated at mean (SD) 10 ± 1 days. The study by Costa 2013 and the study by Romagnoli 2000 were conducted in the same unit in Italy.

Proven sepsis (clinical symptoms and signs of sepsis and positive blood culture for bacteria or fungi) (Outcome 1.10)

Eleven studies including 1039 infants reported on this outcome. EPO did not significantly change the rates of proven sepsis (typical RR 0.95, 95% CI 0.76 to 1.19; typical RD - 0.01, 95% CI -0.06 to 0.03). There was no heterogeneity (RR and RD: I2 = 0%).

Necrotising enterocolitis (NEC) (stage > 2 or stage not reported) (Outcome 1.11)

We included any outcome stated as NEC in this analysis. Eleven studies reporting on 1347 infants were included. EPO did not significantly change the rates of NEC (typical RR 1.07, 95% CI 0.73 to 1.57; typical RD 0.00, 95% CI -0.02 to 0.03). There was no heterogeneity for this outcome (RR and RD: I2 = 0%). Ohls 1995 reported no differences in NEC rates between groups (data not provided).

Intraventricular haemorrhage (IVH); all grades (Outcome 1.12)

Many authors did not state the grade of IVH. We included in this outcome studies in which the grade was not stated and excluded IVH grades III to IV when they were known. A total of nine studies including 789 infants reported on this outcome. EPO did not significantly change the rate of IVH (all grades) (typical RR 1.00, 95% CI 0.73 to 1.38; typical RD 0.00, 95% CI -0.05 to 0.05). There was no heterogeneity for this outcome (RR and RD: I2 = 0%). Ohls 1995 and Ohls 1997 reported no differences in IVH rates between groups (data not provided).

Intraventricular haemorrhage (IVH); grades III and IV (Outcome 1.13)

A total of six studies enrolling 678 infants reported on this outcome. EPO did not significantly change the rate of IVH (grade III and IV) (typical RR 1.03, 95% CI 0.59 to 1.82; typical RD 0.00, 95% CI -0.03 to 0.04). There was no heterogeneity for this outcome for RR but low heterogeneity for RD (RR: I2 = 7%; RD: I2 = 35%).

Periventricular leukomalacia (PVL); cystic changes in the periventricular areas (Outcome 1.14)

Four studies enrolling 290 infants reported on PVL. One study (Fauchère 2008) enrolling 45 infants reported on persisting periventricular echogenicity. We included that study in the analyses. EPO did not significantly change the rate of PVL (typical RR 0.84, 95% CI 0.59 to 1.19; typical RD -0.03, 95% CI -0.08 to 0.03). There was no heterogeneity for this outcome for RR (I2 = 0%) but low heterogeneity for RD (I2 = 47%). The incidence of persisting periventricular echogenicity was very high in the study by Fauchère 2008 with an overall incidence of 79%.

Length of hospital stay (days) (Outcome 1.15)

A total of six studies enrolling 477 infants reported on the length of hospital stay. EPO did not significantly change length of hospital stay (typical MD -1.91, 95% CI -4.35 to 0.54). There was no heterogeneity for this outcome (I2 = 0%).

Avent 2002 reported the median and range (days) for hospital stay across three groups: low dose EPO 32 (5 to 54), high dose EPO 32 (16 to 74) and control group 30 (14 to 46) (P = 0.10 across the three groups).

Haiden 2005 reported on the hospital stay (days, median and range): EPO group 97 (59 to 162) and control group 89 (77 to157) (not statistically significant according to the authors).

Maier 2002 reported on the median (quartiles) for hospital stay: early EPO group 87 (73 to 107), control group 87 (69 to 108).

Bronchopulmonary dysplasia (Outcome 1.16)
Bronchopulmonary dysplasia (BPD) (supplemental oxygen at 28 days of age) (Outcomes table 1.16.1)

One study enrolling 100 infants reported on the use of supplemental oxygen at 28 days. EPO did not significantly change the rate of BPD (supplemental oxygen at 28 days of age) (RR 0.75, 95% CI 0.35 to 1.62; RD -0.06, 95% CI -0.22 to 0.10). Tests for heterogeneity were not applicable. Ohls 1995 and Ohls 1997 reported no differences in BPD rates between groups (data not provided).

Bronchopulmonary dysplasia (BPD) (supplemental oxygen at age 36 weeks postmenstrual age (PMA)) (Outcomes table 1.16.2)

Five studies enrolling 542 infants reported on the use of supplemental oxygen at 36 weeks PMA. EPO did not significantly change the rate of BPD (supplementary oxygen at age 36 weeks PMA) (typical RR 0.99, 95% CI 0.81 to 1.21; typical RD -0.00, 95% CI -0.08 to 0.07). There was no heterogeneity for this outcome (RR and RD: I2 = 0%).

Bronchopulmonary dysplasia (BPD) (age at diagnosis not stated) (Outcomes table 1.16.3)

A total of five studies enrolling 528 infants reported on this outcome. EPO did not significantly change the rate of BPD (age at diagnosis not stated) (typical RR 0.98, 95% CI 0.61 to 1.56; typical RD -0.00, 95% CI -0.05 to 0.05). There was no heterogeneity for this outcome (RR and RD: I2 = 0%).

Neutropenia (Outcome 1.17)

Eleven studies including 1084 infants reported on neutropenia. The non-significant typical RR was 0.81 (95% CI 0.53 to 1.24); typical RD - 0.01 (95% CI -0.04 to 0.02). There was no heterogeneity for this outcome (RR and RD: I2 = 0%).

Hypertension (Outcome 1.18)

A total of seven studies enrolling 824 infants reported on hypertension. In five studies there were no outcomes in either the treatment or the control groups. Therefore, these five studies did not provide any information to the typical RR estimate. The typical RR was 0.97 (95% CI 0.14 to 6.69). All seven studies were included in the typical RD of -0.00 (95% CI -0.01 to 0.01). There was no heterogeneity for this outcome (RR: I2 = 0%; RD: I2 = 0%).

Long-term outcomes assessed at any age beyond one year of age by a validated cognitive; motor; language; or behavioural, school, social interaction, adaptation test (Outcome 1.19)
Mental Developmental Index (MDI) < 70 at 18 to 22 month's corrected age (Outcomes table 1.19)

One study reported on this outcome in 90 children following EPO treatment. The RR was 0.88 (95% CI 0.49 to 1.57); RD -0.04 (95% CI -0.24 to 0.15). These findings were not statistically significant. Tests for heterogeneity were not applicable.

Psychomotor Developmental Index (PDI) < 70 at 18 to 22 months corrected age (Outcome 1.20)

One study reported on this outcome in 90 children following EPO treatment. The RR was 2.33 (95% CI 0.98 to 5.53); RD 0.18 (95% CI 0.01 to 0.35). The RR was not statistically significantly different between the groups but for RD there was an increased risk of having a PDI < 70 at 18 to 22 month's corrected age in the EPO group compared to the control group (P = 0.04) (NNTH 6, 95% CI 3 to 100). Tests for heterogeneity were not applicable.

Cerebral palsy at 18 to 22 months corrected age (Outcome 1.21)

Two studies reported on this outcome in 153 children following EPO treatment. The RR was 0.66 (95% CI 0.31 to 1.37); RD -0.07 (95% CI -0.18 to 0.05). These findings were not statistically significant. There was moderate heterogeneity (RR: I2 = 72%; RD: I2 = 73%).

Any neurodevelopmental impairment at 18 to 22 month's corrected age (Outcome 1.22)

One study reported on this outcome in 99 children following EPO treatment. The RR was 0.97 (95% CI 0.62 to 1.51); RD -0.01 (95% CI -0.21 to 0.18). These findings were not statistically significant. Tests for heterogeneity were not applicable.

Blindness at 18 to 22 month's corrected age (Outcome 1.23)

One study reported on this outcome in 101 children following EPO treatment. There was no significant difference between the groups (RR 0.33, 95% CI 0.01 to 7.84; RD -0.02, 95% CI -0.07 to 0.03). Tests for heterogeneity were not applicable.

Hearing loss at 18 to 22 month's corrected age (Outcome 1.24)

One study reported on this outcome in 98 children. There was no significant difference between the groups (RR 1.04, 95% CI 0.07 to 16.19; RD 0.00, 95% CI -0.06 to 0.06). Tests for heterogeneity were not applicable.

Short-term Neonatal Behavioral Neurological Assessment: Neonatal Behavioral Neurological Assessment at 40 weeks PMA (Outcome 1.25)

One study reported on this outcome in 44 infants. The score was significantly higher in the group that received EPO (MD 1.80, 95% CI 1.26 to 2.34). Tests for heterogeneity were not applicable. This study was written in Chinese and only the abstract was available in English. We have written to the authors to obtain more information but by April 2014 we had not received any feedback.

Bayley Scales of Infant Development (BSID-III) cognitive scores at 18 to 22 months (Outcome 1.26)

One study reported on this outcome in 54 infants. The score was significantly higher in the group that received EPO (MD 10.00, 95% CI 3.06 to 16.94). Tests for heterogeneity were not applicable.

Sudden infant death after discharge (no outcomes table)

No study reported on this outcome.

Any side effects reported in the trials (no outcomes table)

Side effects were specifically reported not to have occurred in nine trials (Carnielli 1992; Maier 1994; Lauterbach 1995; Ohls 1995; Meister 1997; Chang 1998; Lima-Rogel 1998; Fauchère 2008; Khatami 2008). Ohls 2013 reported that side effects were minimal and not different between the groups.

Use of one or more red blood cell transfusions (secondary analysis - based on NICUs using mostly satellite units of red blood cells) (Outcome 1.27)

In a second post hoc analysis to try and explain the between-study heterogeneity for the primary outcome we analyzed the results for the three studies in which most of the NICUs used satellite units of RBCs for transfusion. A total of four studies enrolling 501 infants reported on this outcome. The use of EPO in combination with dedicated RBC transfusion units significantly reduced the use of one or more RBC transfusions (typical RR 0.89, 95% CI 0.80 to 0.99; typical RD -0.08, 95% CI -0.15 to -0.01; NNTB 13, 95% CI 7 to 100). There was no heterogeneity for this outcome (RR and RD: I2 = 0%).

Use of one or more red blood cell transfusions (secondary analysis - based on perceived study quality) (Outcome 1.28)

In a post hoc analysis to try and explain the between-study heterogeneity for the primary outcome, we divided the studies into two groups: 'high quality studies' and 'studies of uncertain quality'.

Use of one or more red blood cell transfusions (secondary analysis - based on perceived high quality studies) (Outcome 1.28.1)

Seven studies enrolling 624 infants were perceived as high quality studies. The RR was 0.82 (95% CI 0.75 to 0.91); RD -0.13 (95% CI -0.20 to -0.07), NNTB 8 (95% CI 5 to 14). There was moderate heterogeneity for this outcome (RR: I2 = 57%; RD: I2 = 62%).

Use of one or more red blood cell transfusions (secondary analysis - based on studies with perceived uncertain quality) (Outcome 1.28.2)

Nine studies enrolling 1037 infants were perceived as of uncertain quality. The RR was 0.76 (95% CI 0.68 to 0.84); RD -0.15 (95% CI -0.20, -0.09); NNTB 7 (95% CI 5 to 11). There was moderate heterogeneity for this outcome (RR and RD: I2 = 55%).

Retinopathy of prematurity (stage >/= 3) in infants treated with EPO before or after eight days of age (Outcome 1.29)

Figure 3

Figure 3.

Forest plot of comparison: 1 Erythropoietin versus placebo or no treatment, outcome: 1.29 Retinopathy of prematurity (stage >/= 3) in infants treated with EPO before or after 8 days of age.

In a third post hoc analysis we combined all studies that reported on ROP >/= 3 regardless of at what age the EPO treatment was initiated. We included the seven studies from analysis 1.9 in this review and three studies from the late EPO review that reported on this outcome. A total of 10 studies enrolling 1303 infants reported on this outcome. There was a significantly increased risk of ROP stage ≥ 3 (typical RR 1.48, 95% CI 1.02 to 2.13; typical RD 0.03, 95% CI 0.00 to 0.06; P = 0.04 for RR and P = 0.03 for RD; NNTH 33, 95% CI 17 to infinity). There was no heterogeneity for RR (12 = 0%) and moderate (I2 = 50) for RD.

A funnel plot for the primary outcome 'use of one or more RBC transfusions' was quite symmetric (Figure 4). A funnel plot for the outcome ROP (stage ≥ 3) (Analysis 1.9; Figure 5) for early EPO treatment was symmetrical with no indication of possible publication bias, making the result more robust. This applied to the analysis of stage ROP ≥ 3 that included all studies regardless of the age of the infant when EPO treatment was initiated (Analysis 1.29; Figure 6).

Figure 4.

Funnel plot of comparison: 1 Erythropoietin versus placebo or no treatment, outcome: 1.1 Use of one or more red blood cell transfusions (low and high dose of EPO).

Figure 5.

Funnel plot of comparison: 1 Erythropoietin versus placebo or no treatment, outcome: 1.9 Retinopathy of prematurity (stage ≥ 3).

Figure 6.

Funnel plot of comparison: 1 Erythropoietin versus placebo or no treatment, outcome: 1.29 Retinopathy of prematurity (stage >/= 3) in infants treated with EPO before or after 8 days of age.

Darbepoietin alfa versus placebo or no treatment (Comparison 2)

Only one study was identified for this comparison (Ohls 2013) and all outcomes and therefore tests for heterogeneity were not applicable.

Primary outcomes
Use of one or more red blood cell transfusions (Outcome 2.1)

One study including 66 infants reported on this outcome. The RR of 0.62 (95% CI 0.38 to 1.02) was not significantly reduced but the RD of -0.24 was (95% CI -0.48 to -0.01).

Secondary outcomes
Total volume (mL/kg) of blood transfused per infant (Outcome 2.2)

One study including 66 infants reported on this outcome. The non-significant MD was -21.0 mL/kg (95% CI -50.7 to 8.7).

Number of blood transfusions per infant (Outcome 2.3)

One study including 66 infants reported on this outcome. The non-significant MD was -1.20 (95% CI -2.48 to 0.08).

Number of donors the infant was exposed to (Outcome 2.4)

One study including 66 infants reported on this outcome. The non-significant MD was -0.50 (95% CI -1.10 to 0.10).

Mortality during initial hospital stay (all causes of mortality) (Outcome 2.5)

One study including 66 infants reported on this outcome. The non-significant RR was 0.33 (95% CI 0.04 to 3.04) and the non-significant RD was -0.06 (95% CI -0.17 to 0.05).

Retinopathy of prematurity (all stages) (Outcome 2.6)

One study including 62 infants reported on this outcome. The non-significant RR was 0.94 (95% CI 0.50 to 1.75) and the non-significant RD was -0.03 (95% CI -0.27 to 0.22).

Retinopathy of prematurity (stage ≥ 3) (Outcome 2.7):

One study including 62 infants reported on this outcome. The non-significant RR was 0.47 (95% CI 0.09 to 2.37) and the non-significant RD was -0.07 (95% CI -0.22 to 0.08).

Necrotizing enterocolitis (stage > 2) (Outcome 2.8):

One study including 62 infants reported on this outcome. The non-significant RR was 0.94 (95% CI 0.14 to 6.24) and the non-significant RD was -0.00 (95% CI -0.13 to 0.12).

Proven sepsis (Outcome 2.9):

One study including 62 infants reported on this outcome. The non-significant RR was 1.13 (95% CI 0.38 to 3.30) and the non-significant RD was 0.02 (95% CI -0.17 to 0.21).

Intraventricular haemorrhage (grade III and IV) (Outcome 2.10):

One study including 62 infants reported on this outcome. The non-significant RR was 0.40 (95% CI 0.11 to 1.41) and the non-significant RD was -0.14 (95% CI -0.32 to 0.04).

Periventricular leukomalacia (Outcome 2.11)

One study including 62 infants reported on this outcome. There were no cases in either of the two groups. The RR was not estimable and the non-significant RD was 0.00 (95% CI -0.06 to 0.06).

Bronchopulmonary dysplasia (supplemental oxygen at 36 weeks PMA) (Outcome 2.12)

One study including 62 infants reported on this outcome. The non-significant RR was 1.03 (95% CI 0.73 to 1.46) and the non-significant RD was 0.02 (95% CI -0.21 to 0.25).

Length of hospital stay (days) (Outcome 2.13)

One study including 62 infants reported on this outcome. The non-significant MD was 2 days (95% CI -17.84 to 21.84).

Hypertension (Outcome 2.14)

One study including 62 infants reported on this outcome. The non-significant RR was 1.88 (95% CI 0.18 to 19.63) and the non-significant RD was 0.03 (95% CI -0.08 to 0.13).

Neutropenia (Outcome 2.15)

One study including 62 infants reported on this outcome. There were no cases in either of the two groups. The RR was not estimable and the non-significant RD was 0.00 (95% CI -0.06 to 0.06).

Cerebral palsy at 18 to 22 months (Outcome 2:16)

One study including 51 infants reported on this outcome. The non-significant RR was 0.08 (95% CI 0.00 to 1.40) (p = 0.08) and the significantly reduced RD was -0.21 (95% CI -0.38 to -0.04) (P = 0.02).

BSID-III cognitive scores at 18 to 22 months (Outcome 2:17)

One study including 51 infants reported on this outcome. The significantly increased MD was 9.00 (95% CI 3.33 to 14.67).

Discussion

Summary of main results

Twenty-seven studies conducted in 20 countries met the inclusion criteria. Nineteen studies were excluded. The accepted studies included a total of 2047 preterm infants and reported on at least one of the outcomes of interests for this systematic review. The study quality varied and information regarding whether the allocation was concealed or not was often missing. We judged that there was proper random sequence generation in eight studies and that the allocation to study groups was concealed in 14 studies. A placebo or sham injection was used in 12 studies ensuring blinding of the intervention. No study was reported according to the CONSORT statement (Begg 1996). Sample sizes were relatively small and ranged from 19 to 292 infants enrolled. Long-term (18 to 22 months corrected age) outcomes were reported only in two studies (Ohls 2001A; Ohls 2013). In the study by Ohls (Ohls 2001A) the follow-up rates were low, 71 % in the EPO group and 73% of the survivors in the control group. In the study by Ohls 2013 that enrolled 102 infants, seven died prior to discharge from hospital and 14 infants were lost to follow-up. A funnel plot for the primary outcome 'use of one or more red blood cell transfusions' was asymmetric with a relative absence of smaller studies not having a protective effect (Figure 4). This may indicate that smaller studies with 'negative' results have not been published.

In only one study (Arif 2005) did the authors specifically state that infants were not eligible to enter the study if they previously had received a red blood cell transfusion. In three studies it was stated that infants were included if they had received prior red blood cell transfusions; the rates varied between 14% and 32% (Maier 1994; Maier 2002) and in the study by Ohls 2013 the rate was 17%. Although often not stated, it is likely that infants who had received blood transfusion prior to study entry were not excluded as this was not mentioned as an exclusion criterion. All studies except one followed guidelines (with tremendous variation between studies) for red blood cell transfusions (see Additional table Table 1).

The use of early EPO in preterm infants (27 studies, n = 2209) has been extensively studied. The 2012 update did not identify any new studies for inclusion but did find an additional five for exclusion. The 2009 update of our review added 145 infants. For this 2013 update, which was initiated following a reader's feedback, we excluded four studies (Romagnoli 2000; Bierer 2006; Saeidi 2012; Costa 2013). Bierer 2006 was excluded as it was a duplicate publication (n = 16). In the study by Romagnoli and co-workers (Romagnoli 2000) (n = 230) the intervention started at a mean (± SD) age of 10 (± 1) days and the study was moved to the late EPO review. The study by Saeidi and coworkers was excluded as it compared administration of oral EPO with subcutaneous EPO (Saeidi 2012). Costa and co-workers compared intravenous with subcutaneous administration of EPO (Costa 2013).

The use of red blood cells from satellite bag-equipped, dedicated units decreases donor exposure in low birth weight infants (Lee 1995). In a single-centre report the red blood cell transfusion guidelines for infants with birth weight < 1000 g were changed three times (in 1989, 1991, and 1995) and became more restrictive with each change (Maier 2000). The changes were made in association with the introduction of new EPO trials. Since 1990, the primary red blood cell pack was divided into three to four satellite packs. The median number of transfusions decreased from seven in the first period to two in the third period. Donor exposure decreased from five to one, and the blood volume transfused decreased from 131 to 37 mL/kg. According to the authors, the changing transfusion practices were due to several factors including stricter transfusion guidelines, increased adherence to transfusion guidelines, efforts to reduce sampling loss and EPO therapy. The authors suggested that "not using transfusions to replace defined blood volume loss had the highest impact on reduced transfusions" (Maier 2000).

It has been postulated that early red blood cell transfusions may increase the risk of the extension of IVH grade I to higher grades (Baer 2011) and that late red blood cell transfusions may be associated with NEC (Blau 2011). It has been suggested that even small reductions in the number of transfusions given to neonates could have an impact (Ohls 2013; Ohls 2013a) on the occurrence of IVH and NEC. As most IVHs and extensions of IVHs occurs within the first 72 hours of life (Dolfin 1983), it is difficult to imagine that early EPO treatment with a very small reduction in transfusions over the whole study period (< 1) could have an impact on the incidence of IVH and extension from a grade 1 to a grade 3 or 4 haemorrhage. To date most studies have started the intervention beyond 72 hours of age. There were no significant reductions in IVH or NEC in either this early EPO review or the late EPO review (New Reference). The results for a possible association between transfusions in neonates and the occurrence of transfusion-associated NEC vary depending on study design (Kirpalani 2012). A lower incidence of NEC was found to be associated with more transfusions in randomized controlled trial designs, opposite to that seen in observational studies (transfusions are associate with NEC) (Kirpalani 2012).

In this update of the review the study by Romagnoli and co-workers (Romagnoli 2000) was excluded and moved to the late EPO review. In that study the incidence of stage ROP ≥ 3 was statistically significantly higher in the EPO group (17.4 %) versus the control group (7.8%). When this study was excluded from the early EPO review the outcome of stage ROP ≥ 3 was no longer statistically significantly increased but with a trend towards an increase in this adverse outcome (RR 1.37, 95% CI 0.87 to 2.17) (Figure 2). As the concerns for an increased risk of ROP stage ≥ 3 remain we performed a post hoc analysis in which we included the seven studies in this early EPO review and three studies that initiated EPO treatment beyond eight days of age. The results show an increased risk of ROP stage ≥ 3 (RR 1.48, 95% CI 1.02 to 2.13; RD 0.03, 0.00 to 0.06; NNT 33, 95% CI 17 to infinity) (Figure 3). There was no heterogeneity for RR (I2 = 0%) but moderate heterogeneity for RD (I2 = 50%). There does not seem to be any evidence for possible publication bias for this outcome as the funnel plots (Figure 5; Figure 6) are symmetrical. With so many secondary outcomes included this could be a chance finding. Only one study had as its primary objective to "Evaluate whether EPO and iron supplementation increase the risk of retinopathy of prematurity" (Romagnoli 2000). In that study there was a statistically significant increased risk of ROP following EPO treatment. The authors speculated that iron supplementation could be a contributing factor. It is of note that in the latest randomized controlled trial by Romagnoli and co-workers (Costa 2013) in which administration of intravenous versus subcutaneous administration of early EPO was studied the overall incidence of ROP ≥ 3 was 15% (16% in the intravenous EPO group and 14% in the subcutaneous group). The incidence is very close to the 17% in the previous Romagnoli study (Romagnoli 2000) in which the high incidence of stage ≥ 3 ROP was of concern. In our early versus late EPO review (New Reference) we noted an increase in ROP with early EPO treatment but not in the late EPO review (New Reference). It may be that the infant is at greatest risk if EPO is administered early, starting in their first week of life. In an observational study Rudzinska 2002 reported an increased risk of ROP following early versus late treatment with EPO.

Manzoni 2005 reported data on 695 neonates with birth weights < 1500 g who were admitted between 1997 and 2004. Threshold ROP occurred in 31.4% (54 of 172) of infants < 1000 g who received EPO therapy as compared with 19.6% (22 of 112) of those who did not receive EPO (P = 0 .01 in univariate analysis, P = 0.04 in multivariate analysis) (P values according to authors). The authors suggested that EPO is an additional, independent predictor of severe threshold ROP in infants < 1000 g (Manzoni 2005). In an analysis of data from a neonatal network in South America, Musante 2006 and co-workers found that treatment with EPO independently increases the risk of ROP and severe ROP. The incidence and severity of ROP may depend on the dose of EPO (Liu 2006). In a murine normoxia-induced proliferative retinopathy model, Morita 2003 et al implicated EPO as a key factor in the development ROP, especially in the development of neo-vascularisation. The authors suggested a possible therapeutic use for EPO and vascular endothelial growth factor (VEGF) inhibitors in the treatment of ROP (Morita 2003). Watanabe and co-workers (Watanabe 2005) studied vitreous EPO levels in 73 adult patients with proliferative diabetic retinopathy and found that the median level was significantly higher (P < 0.001) than in 71 patients without diabetes. They suggested that EPO is a potent ischaemia-induced angiogenic factor that acts independently of VEGF during retinal angiogenesis in proliferative diabetic retinopathy (Watanabe 2005).

For the update in 2012 we identified several case-control and cohort studies that assessed the possible association between treatment with EPO and ROP. Aulak and co-workers (Aulakh 2002) in a retrospective study of 336 infants did not find that EPO treatment was associated with ROP. Similarily Shah and co-workers (Shah 2010) in a study involving 85 very low birth weight infants (56 infants received EPO and 29 did not) found no significant difference in the incidence or severity of ROP between EPO treated and the non-treated infants. However, in a previous abstract (Shah 2005) with the same number of infants studied in the two groups (likely to be the same cohort), they found a significant weak positive correlation between the duration of EPO treatment and development of pre-threshold disease.

Rangaswamy and co-workers (Rangaswamy 2011) in a retrospective study including 199 infants noted an increased risk of ROP stage 1 (P = 0.01) and stage 3 (P = 0.05) in infants who received a long course of EPO (> two weeks) versus a short course (< two weeks). EPO treatment did not improve the neurodevelopmental outcomes within the first two years of life (Rangaswamy 2011). Manzoni and co-workers (Manzoni 2008), in a retrospective study including 197 infants from two NICUs in Italy, identified EPO as an independent predictor of threshold ROP in extremely low birth weight infants (P = 0.04) in a multivariate logistic regression model. In another study from Italy, including 106 infants, De Luca and co-workers (De Luca 2001) identified in a logistic regression model that oxygen therapy and the number of doses of EPO related to the incidence of ROP. Brown and co-workers (Brown 2006) conducted a retrospective cohort study of 327 infants. The probability of progression of retinopathy was estimated by logistic regression multivariate analysis. Recombinant EPO exposure, as total six-week dose, was independently associated with an increased risk of progression of retinopathy (OR 1.27 per 500 units/kg, 95% CI 1.04 to 1.55; P = 0.02). Postnatal day of recombinant EPO initiation was associated with retinopathy risk but did not reach conventional statistical significance (OR 1.07, CI 1.00 to 1.14; P = 0.07) (Brown 2006).

Most of these non-randomised studies support an association between early EPO and ROP. Therefore, our finding from randomized controlled trials of a possibly increased risk of ROP following administration of EPO is of concern.

In the analysis of 'retinopathy of prematurity (stage ≥ 3)' (Analysis 1.9), four of the seven included studies used a combination of high EPO and high iron doses (Ohls 2001A; Ohls 2001B; Haiden 2005; Ohls 2013). In two studies the iron dose was higher in the EPO treated group (Ohls 2001A; Ohls 2001B); and in one study iron was provided intravenously in the EPO group from the initiation of therapy whereas the control group received oral iron from the 15th day of life (Haiden 2005). In one (high EPO) study (Maier 1994) both groups received the same amount of iron (2 mg/kg/day). Therefore, It is possible that the higher doses of iron were the cause of or contributed to the higher rates of ROP (stage ≥ 3) in the EPO treated infants in these trials. In one study (Fauchère 2008) a high dose of EPO was used only during the first few days of life and the authors do not state if iron was used. However, in the study by Maier 2002, which used a combination of high EPO and low iron, the point estimate for stage ≥ 3 was quite high (RR 2.22, 95% CI 0.83 to 5.94).

Administration of EPO could potentially have a neuroprotective effect in preterm infants, especially in infants with perinatal asphyxia (Dame 2001; Juul 2002). This aspect of EPO use in neonates has not been systematically reviewed. Two studies included in this review used EPO as a neuroprotective agent (Fauchère 2008; He 2008). The study of Fauchère 2008 (Fauchère 2008) used early EPO with the goal of neuroprotection in very preterm infants. The primary hypothesis of this pilot study was that "the rate of survivors without brain injury (IVH and PVL) including ROP are not affected by administration of three high doses of EPO early after birth". The percentage of infants who survived without brain injury or ROP was 53% in the EPO group and 60% in the placebo group. However, five infants died in the EPO group versus none in the placebo group. The RR for mortality was higher in this study when compared to the results of other trials.

In the study by He 2008 the purpose was to evaluate the effect of early EPO therapy on neurobehavioural development in preterm seven-day old infants. This study was written in Chinese and only the abstract in English was understandable to us (we have contacted the authors but have not received an answer). Neonatal Behavioral Neurological Assessment at 40 weeks PMA and Gesell Developmental Schedule at six and 12 months after birth were used to assess the infants. The results favoured the EPO group.

We excluded the study by Zhu 2009 as the population was term infants with moderate to severe hypoxic Ischaemic encephalopathy and did not meet our inclusion criterion of PMA < 37 weeks. The authors reported that repeated low doses of EPO reduced the risk of disability for infants with moderate hypoxic ischaemic encephalopathy but not for those with severe hypoxic ischaemic encephalopathy. To date, early EPO meta-analyses have not shown a significant reduction in mortality, proven sepsis, NEC, IVH, PVL, or BPD. Long-term neurodevelopmental outcomes at 18 to 22 months have shown conflicting results with one study showing an increased risk of Psychomotor Development Indexes (PDI) < 70 (of borderline significance). As BPD, ultrasonographic signs of brain injury, severe ROP and infection strongly predict the risk of later death or neurosensory impairment on 18-month outcomes of extremely low birth weight infants (Schmidt 2003; Bassler 2009) it is difficult to hypothesize that early treatment with EPO could have a neuroprotective effect in preterm infants. A number of trials investigation the neuroprotective, long-term effects as well as the risk of ROP with early EPO have been registered with ClinicalTrials.gov (Identifiers: NCT 00910234, NCT 00589953, NCT 00413946, NCT 00945789, NCT 00719407, NCT 00808704). The results of these trials will be reviewed separately (Yu 2010).

Any future studies of EPO in preterm infants should include ROP as an outcome measure of importance and data monitoring and safety committees should be provided with this information on an ongoing basis. We will try to obtain unpublished data from the authors of published studies. It is likely that the outcome of ROP has been recorded in study protocols or, as most studies are of small sample size, the outcome could be obtained from patients' charts. Until more information is available, either from published or ongoing studies regarding ROP, we do not recommend any new trials of early EPO to reduce blood transfusions, especially in view of the limited benefits identified in this extensive review.

For the present, it is important that NICUs develop practice guidelines to limit blood losses and donor exposure in neonates. The use of satellite packs and conservative transfusion guidelines reduces the exposure to multiple donors during the hospital stay. The need for red blood cell transfusions is linked to the loss of blood from sampling for laboratory testing.

Overall completeness and applicability of evidence

This review provides evidence that early administration of EPO significantly reduces the 'use of one or more blood transfusions' following study entry with a low NNTB of 7 and a narrow 95% CI of 6 to 10. From our results we cannot make a recommendation with regard to the best combination of a high or low dose EPO and high or low dose of iron. We had arbitrarily set a cut-off of ≤ 5 mg/kg/day of oral intake of iron for low and high doses of iron. When we conducted the review we discovered that several studies started with intravenous administration of iron in variable doses and we considered any intravenous dose of iron as a high dose. Early EPO significantly reduces the total volume (mL/kg) of red blood cells transfused (7 mL, 95% CI 12 to 2 mL), the number of red blood cell transfusions per infant (typical MD -0.27, 95% CI -0.42 to -0.12) and the number of donor exposures (typical MD -0.54, 95% CI -0.89 to -0.20). For these outcomes the effect sizes were small and are likely to be of limited clinical importance.

Overall, early EPO provides very limited clinical benefits. It is possibly associated with an increased risk of ROP stage ≥ 3 (when early and late exposures are combined; in early versus late administration of EPO) and, therefore, its use is not recommended.

Quality of the evidence

There was a report of proper random sequence generation in eight studies (Soubasi 1993; Soubasi 1995; Meister 1997; Soubasi 2000; Meyer 2003; Arif 2005; Fauchère 2008; Ohls 2013). The allocation to study groups was interpreted by us as concealed in 14 studies (Obladen 1991; Soubasi 1993; Maier 1994; Ohls 1997; Romagnoli 2000; Salvado 2000; Ohls 2001A; Ohls 2001B; Maier 2002; Meyer 2003; Haiden 2005; Fauchère 2008; Khatami 2008; Ohls 2013). Placebo or sham injections were used in 12 studies (Soubasi 1993; Maier 1994; Ohls 1995; Ohls 1997; Lima-Rogel 1998; Salvado 2000; Ohls 2001A; Ohls 2001B; Maier 2002; Meyer 2003; Fauchère 2008; Ohls 2013). Sample sizes were generally small and ranging from 19 (Lauterbach 1995) to 292 (Arif 2005) infants enrolled. Seven studies enrolled 100 infants or more. No study was reported according to the CONSORT statement (Begg 1996). There was complete follow-up in all studies.

There was statistically significant (moderate) heterogeneity for the primary outcome ('use of one or more blood transfusions') as well as for two important secondary outcomes (the 'total volume of blood transfused per infant' and 'number of transfusions per infant'). In an attempt to explore the reason for the between-study heterogeneity we performed a post hoc analysis for the primary outcome. We divided the studies into two groups of 'high quality studies' (studies with concealed allocation and the use of a placebo or sham injections) and 'studies of uncertain quality' (studies in which those criteria could not be ascertained). There were no substantial differences between the point estimates for the effect size for the two groups nor were there any real differences in the degree of heterogeneity when all studies were analyzed together or in two separate groups by quality. In our late EPO review (New Reference) some of the heterogeneity could be explained by the same exercise. There could be other explanations for the heterogeneity such as differences in dosing regimens for EPO and iron, EPO preparations, blood sampling, indications for transfusion (the rates of transfusions in the control groups varied), use of non-invasive monitoring, general standards of care and baseline characteristics among the infants enrolled. In an additional post hoc analysis we analyzed the results from four multi-centre studies in which most of the centres used satellite packs of red blood cells for multiple transfusions to the same infant. The use of EPO in combination with dedicated red blood cell transfusion units did significantly reduce the use of one or more red blood cell transfusions. There was no statistically significant heterogeneity for this outcome.

To date, only a limited number of infants have been followed long term (Ohls 2001A; Ohls 2013). From the one study published as a full report (Ohls 2001A) there is no indication that early EPO would have a neuroprotective effect and improve neurodevelopmental outcomes at 18 to 22 months' corrected age. In fact, the study showed a statistically significant increased risk for PDI < 70 at 18 to 22 months (RD 0.18, 95% CI 0.01, 0.35) with the RR showing a similar trend (RR 2.33, 95% CI 0.98 to 5.53). In the Ohls 2013 study outcomes at 18 to 22 months have been published in abstract form only. In that study significantly better mean BSID-III cognitive scores were reported in the early EPO group and the darbepoetin groups compared with the control groups. Becasue of the very small number of infants followed to 18 to 22 months these results should be viewed with caution.

Darbepoetin needs to be studied in larger trials before any recommendations can be made. From the few infants studied to date darbepoetin appears to have similar effectiveness as EPO. Too few infants have been studied to assess its safety. Darbepoetin does have the advantage of fewer injections required and thus reducing painful stimuli in this vulnerable population.

Potential biases in the review process

We are not aware of any potential biases in our review process.

Agreements and disagreements with other studies or reviews

Previous systematic reviews (which included fewer studies than in our reviews) have not included ROP (or other common neonatal outcomes) as outcome measures (Vamvakas 2001; Garcia 2002; Kotto-Kome 2004). Those reviews noted similar effect sizes for transfusion needs and reported on statistically significant between-study heterogeneity.

Authors' conclusions

Implications for practice

Early administration of EPO reduces the use of one or more red blood cell transfusions, the volume of red blood cells transfused, and the number of donors and transfusions the infant is exposed to following study entry. Donor exposure is probably not avoidable as most studies included infants who had received red cell transfusions prior to trial entry. Although statistically significant, the reductions are of limited clinical importance. There was a significant increase in the rate of ROP (stage ≥ 3) with EPO use (early and late use of EPO). Animal data and observational studies in humans support a possible association between treatment with EPO and the development of ROP. EPO does not significantly reduce or increase any of many other important adverse outcomes including mortality, IVH and NEC. In view of the limited clinical benefits and the possible increase in ROP (stage ≥ 3) the administration of early EPO is not recommended.

Implications for research

Future research should focus on strategies to minimize red blood cell donor exposure during the first week of life, when the likelihood for the need for red blood cell transfusion is at its peak. Such strategies which include the use of satellite packs in combination with late EPO treatment may reduce further donor exposure. There is a concern that early EPO exposure increases the risk of ROP, a serious complication of preterm birth. This increased risk could be associated with higher doses of iron used in the early EPO group of the trials. Ongoing studies must include ROP as an outcome measure of importance and data monitoring and safety committees should be provided with this information on an ongoing basis. Until more information is available, either from published studies or ongoing studies regarding ROP, we do not recommend any new trials of early EPO especially in view of the limited clinical benefits identified in this extensive review. Futher long-term follow-up data are needed.

Acknowledgements

We are thankful to Dr Rolf Maier, Zentrum für Kinder- und Jugendmedizin, Philipps-Universität, Marburg, Germany, Dr Gulcan Türker, University of Kocaeli, Kocaeli, Turkey, Dr Robin K. Ohls, University of New Mexico, Albuquerque, New Mexico, USA and Dr Constantion Romagnoli, Division of Neonatology, Catholic University of Rome, Rome, Italy, who provided us with additional information regarding their studies.

We would like to thank Ms Elizabeth Uleryk, Chief Librarian, The Hospital for Sick Children (SickKids), Toronto, Ontario, Canada, for developing the search strategy for this review.

Ms Yolanda R Brosseau, Managing Editor, Cochrane Neonatal Review Group conducted the literature searches in 2012. She and Colleen M Ovelman, Trial Search Coordinator and Webmaster, Cochrane Neonatal Review Group conducted the literature searches in July 2013.

Dr Silvio Gonzalez, Departmental Fellow, Division of Neonatology, The Hospital for Sick Children (SickKids), Toronto, Ontario, Canada, helped with the translation of sections of two papers from Spanish to English. Mrs Eva Ohlsson, Toronto, Ontario, Canada, helped with the translation of sections of one paper from Polish to English.

Data and analyses

Download statistical data

Comparison 1. Erythropoietin versus placebo or no treatment
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Use of one or more red blood cell transfusions (low and high dose of EPO)161661Risk Ratio (M-H, Fixed, 95% CI)0.79 [0.73, 0.85]
2 Use of one or more blood transfusions (high dose of EPO)141228Risk Ratio (M-H, Fixed, 95% CI)0.79 [0.73, 0.85]
2.1 High dose iron11863Risk Ratio (M-H, Fixed, 95% CI)0.84 [0.77, 0.92]
2.2 Low dose iron3365Risk Ratio (M-H, Fixed, 95% CI)0.66 [0.55, 0.80]
3 Use of one or more red blood cell transfusions (low dose EPO)4484Risk Ratio (M-H, Fixed, 95% CI)0.77 [0.65, 0.91]
3.1 High dose iron2322Risk Ratio (M-H, Fixed, 95% CI)0.75 [0.61, 0.93]
3.2 Low dose iron2162Risk Ratio (M-H, Fixed, 95% CI)0.80 [0.60, 1.07]
4 Total volume (mL/kg) of blood transfused per infant7581Mean Difference (IV, Fixed, 95% CI)-6.82 [-11.52, -2.11]
5 Number of red blood transfusions per infant13951Mean Difference (IV, Fixed, 95% CI)-0.27 [-0.42, -0.12]
6 Number of donors to whom the infant was exposed5 Mean Difference (IV, Fixed, 95% CI)Subtotals only
6.1 Among all randomised infants3254Mean Difference (IV, Fixed, 95% CI)-0.54 [-0.89, -0.20]
6.2 Among infants who were transfused2290Mean Difference (IV, Fixed, 95% CI)0.05 [-0.33, 0.42]
7 Mortality during initial hospital stay (all causes of mortality)161656Risk Ratio (M-H, Fixed, 95% CI)0.91 [0.68, 1.22]
8 Retinopathy of prematurity (all stages or stage not reported)8982Risk Ratio (M-H, Fixed, 95% CI)0.99 [0.81, 1.21]
9 Retinopathy of prematurity (stage ≥ 3)7801Risk Ratio (M-H, Fixed, 95% CI)1.37 [0.87, 2.17]
10 Proven sepsis111039Risk Ratio (M-H, Fixed, 95% CI)0.95 [0.76, 1.19]
11 Necrotizing enterocolitis (stage not reported)111347Risk Ratio (M-H, Fixed, 95% CI)1.07 [0.73, 1.57]
12 Intraventricular haemorrhage (all grades)9789Risk Ratio (M-H, Fixed, 95% CI)1.00 [0.73, 1.38]
13 Intraventricular haemorrhage (grade III and IV)6678Risk Ratio (M-H, Fixed, 95% CI)1.03 [0.59, 1.82]
14 Periventricular leukomalacia4290Risk Ratio (M-H, Fixed, 95% CI)0.84 [0.59, 1.19]
15 Length of hospital stay (days)6477Mean Difference (IV, Fixed, 95% CI)-1.91 [-4.35, 0.54]
16 Bronchopulmonary dysplasia11 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
16.1 Supplemental oxygen at 28 days of age1100Risk Ratio (M-H, Fixed, 95% CI)0.75 [0.35, 1.62]
16.2 Supplemental oxygen at 36 weeks5542Risk Ratio (M-H, Fixed, 95% CI)0.99 [0.81, 1.21]
16.3 Age at diagnosis not stated5528Risk Ratio (M-H, Fixed, 95% CI)0.98 [0.61, 1.56]
17 Neutropenia111084Risk Ratio (M-H, Fixed, 95% CI)0.81 [0.53, 1.24]
18 Hypertension7824Risk Ratio (M-H, Fixed, 95% CI)0.97 [0.14, 6.69]
19 MDI < 70 at 18 to 22 months' corrected age (in children examined)190Risk Ratio (M-H, Fixed, 95% CI)0.88 [0.49, 1.57]
20 PDI < 70 at 18 - 22 months' corrected age (in children examined)190Risk Ratio (M-H, Fixed, 95% CI)2.33 [0.98, 5.53]
21 Cerebral palsy at 18 - 22 months' corrected age (in children examined)2153Risk Ratio (M-H, Fixed, 95% CI)0.66 [0.31, 1.37]
22 Any neurodevelopmental impairment at 18-22 month's corrected age (in children examined)199Risk Ratio (M-H, Fixed, 95% CI)0.97 [0.62, 1.51]
23 Blindness at 18 to 22 month's corrected age1101Risk Ratio (M-H, Fixed, 95% CI)0.33 [0.01, 7.84]
24 Hearing loss at 18 to 22 month's corrected age198Risk Ratio (M-H, Fixed, 95% CI)1.04 [0.07, 16.19]
25 Neonatal Behavioral Neurological Assessment at 40 weeks PMA144Mean Difference (IV, Fixed, 95% CI)1.80 [1.26, 2.34]
26 BSID-III cognitive scores at 18-22 months154Mean Difference (IV, Fixed, 95% CI)10.0 [3.06, 16.94]
27 Use of one or more red blood cell transfusions (in NICUs using mostly satellite units of red blood cells)4501Risk Ratio (M-H, Fixed, 95% CI)0.89 [0.80, 0.99]
28 Use of one or more red blood cell transfusions (secondary analysis)161661Risk Ratio (M-H, Fixed, 95% CI)0.79 [0.73, 0.85]
28.1 High quality studies7624Risk Ratio (M-H, Fixed, 95% CI)0.82 [0.75, 0.91]
28.2 Studies of uncertain quality91037Risk Ratio (M-H, Fixed, 95% CI)0.76 [0.68, 0.84]
29 Retinopathy of prematurity (stage >/= 3) in infants treated with EPO before or after 8 days of age101303Risk Ratio (M-H, Fixed, 95% CI)1.48 [1.02, 2.13]
Analysis 1.1.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 1 Use of one or more red blood cell transfusions (low and high dose of EPO).

Analysis 1.2.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 2 Use of one or more blood transfusions (high dose of EPO).

Analysis 1.3.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 3 Use of one or more red blood cell transfusions (low dose EPO).

Analysis 1.4.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 4 Total volume (mL/kg) of blood transfused per infant.

Analysis 1.5.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 5 Number of red blood transfusions per infant.

Analysis 1.6.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 6 Number of donors to whom the infant was exposed.

Analysis 1.7.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 7 Mortality during initial hospital stay (all causes of mortality).

Analysis 1.8.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 8 Retinopathy of prematurity (all stages or stage not reported).

Analysis 1.9.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 9 Retinopathy of prematurity (stage ≥ 3).

Analysis 1.10.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 10 Proven sepsis.

Analysis 1.11.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 11 Necrotizing enterocolitis (stage not reported).

Analysis 1.12.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 12 Intraventricular haemorrhage (all grades).

Analysis 1.13.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 13 Intraventricular haemorrhage (grade III and IV).

Analysis 1.14.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 14 Periventricular leukomalacia.

Analysis 1.15.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 15 Length of hospital stay (days).

Analysis 1.16.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 16 Bronchopulmonary dysplasia.

Analysis 1.17.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 17 Neutropenia.

Analysis 1.18.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 18 Hypertension.

Analysis 1.19.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 19 MDI < 70 at 18 to 22 months' corrected age (in children examined).

Analysis 1.20.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 20 PDI < 70 at 18 - 22 months' corrected age (in children examined).

Analysis 1.21.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 21 Cerebral palsy at 18 - 22 months' corrected age (in children examined).

Analysis 1.22.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 22 Any neurodevelopmental impairment at 18-22 month's corrected age (in children examined).

Analysis 1.23.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 23 Blindness at 18 to 22 month's corrected age.

Analysis 1.24.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 24 Hearing loss at 18 to 22 month's corrected age.

Analysis 1.25.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 25 Neonatal Behavioral Neurological Assessment at 40 weeks PMA.

Analysis 1.26.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 26 BSID-III cognitive scores at 18-22 months.

Analysis 1.27.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 27 Use of one or more red blood cell transfusions (in NICUs using mostly satellite units of red blood cells).

Analysis 1.28.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 28 Use of one or more red blood cell transfusions (secondary analysis).

Analysis 1.29.

Comparison 1 Erythropoietin versus placebo or no treatment, Outcome 29 Retinopathy of prematurity (stage >/= 3) in infants treated with EPO before or after 8 days of age.

Comparison 2. Darbepoetin alfa versus placebo or no treatment
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Use of one or more red blood cell transfusions166Risk Ratio (M-H, Fixed, 95% CI)0.62 [0.38, 1.02]
2 Total volume (mL/kg) of blood transfused per infant166Mean Difference (IV, Fixed, 95% CI)-21.0 [-50.72, 8.72]
3 Number of blood transfusions per infant166Mean Difference (IV, Fixed, 95% CI)-1.2 [-2.48, 0.08]
4 Number of donors the infant was exposed to166Mean Difference (IV, Fixed, 95% CI)-0.5 [-1.10, 0.10]
5 Mortality during initial hospital stay (all causes of mortality)166Risk Ratio (M-H, Fixed, 95% CI)0.33 [0.04, 3.04]
6 Retinopathy of prematurity (all stages)162Risk Ratio (M-H, Fixed, 95% CI)0.94 [0.50, 1.75]
7 Retinopathy of prematurity (stage ≥ 3)162Risk Ratio (M-H, Fixed, 95% CI)0.47 [0.09, 2.37]
8 Necrotizing enterocolitis (> stage 2)162Risk Ratio (M-H, Fixed, 95% CI)0.94 [0.14, 6.24]
9 Proven sepsis162Risk Ratio (M-H, Fixed, 95% CI)1.13 [0.38, 3.30]
10 Intraventricular haemorrhage (grade III and IV)162Risk Ratio (M-H, Fixed, 95% CI)0.40 [0.11, 1.41]
11 Periventricular leukomalacia162Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
12 Bronchopulmonary dysplasia (supplemental oxygen at 36 weeks PMA)162Risk Ratio (M-H, Fixed, 95% CI)1.03 [0.73, 1.46]
13 Length of hospital stay (days)162Mean Difference (IV, Fixed, 95% CI)2.0 [-17.84, 21.84]
14 Hypertension162Risk Ratio (M-H, Fixed, 95% CI)1.88 [0.18, 19.63]
15 Neutropenia162Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
16 Cerebral palsy at 18-22 months151Risk Ratio (M-H, Fixed, 95% CI)0.08 [0.00, 1.40]
17 BSID-III cognitive scores at 18-22 months151Mean Difference (IV, Fixed, 95% CI)9.0 [3.33, 14.67]
Analysis 2.1.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 1 Use of one or more red blood cell transfusions.

Analysis 2.2.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 2 Total volume (mL/kg) of blood transfused per infant.

Analysis 2.3.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 3 Number of blood transfusions per infant.

Analysis 2.4.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 4 Number of donors the infant was exposed to.

Analysis 2.5.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 5 Mortality during initial hospital stay (all causes of mortality).

Analysis 2.6.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 6 Retinopathy of prematurity (all stages).

Analysis 2.7.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 7 Retinopathy of prematurity (stage ≥ 3).

Analysis 2.8.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 8 Necrotizing enterocolitis (> stage 2).

Analysis 2.9.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 9 Proven sepsis.

Analysis 2.10.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 10 Intraventricular haemorrhage (grade III and IV).

Analysis 2.11.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 11 Periventricular leukomalacia.

Analysis 2.12.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 12 Bronchopulmonary dysplasia (supplemental oxygen at 36 weeks PMA).

Analysis 2.13.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 13 Length of hospital stay (days).

Analysis 2.14.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 14 Hypertension.

Analysis 2.15.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 15 Neutropenia.

Analysis 2.16.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 16 Cerebral palsy at 18-22 months.

Analysis 2.17.

Comparison 2 Darbepoetin alfa versus placebo or no treatment, Outcome 17 BSID-III cognitive scores at 18-22 months.

Feedback

Feedback from Dr. Robin Ohls, 27 March 2013

Summary

This unscheduled update was initiated following feedback from Dr Robin Ohls. Our inclusion of the study by Dr Romagnoli and co-workers (Romagnoli 2000) in this review (early EPO review) was questioned by Dr Ohls (Ohls 2013a), who suggested the study should be included in the late EPO review (New Reference). In addition, Dr Ohls informed us that the study by Bierer and co-workers (Bierer 2006) was a report of a subgroup of the Ohls 2001A study.

Reply

We contacted Dr Romagnoli and he informed us that the mean (± SD) age of the infants when EPO treatment was started was 10 ± 1 days. We therefore moved the study to the late EPO review. It could not be ascertained from the published report that the study by Bierer 2006 was a duplicate publication. We excluded the study by Bierer and co-workers (Bierer 2006) as all outcomes were reported in the study by Ohls 2001A.

Contributors

Ohls, Romagnoli, Ohlsson, Aher.

What's new

DateEventDescription
19 July 2016AmendedMinor edits

History

Protocol first published: Issue 3, 2004
Review first published: Issue 3, 2006

DateEventDescription
9 September 2013New citation required and conclusions have changed

This unscheduled update was initiated following feedback from Dr Robin Ohls. Our inclusion of the study by Dr Romagnoli and co-workers (Romagnoli 2000) in this review (early EPO review) was questioned by Dr Ohls (Ohls 2013a), who suggested the study should be included in the late EPO review (New Reference). We contacted Dr Romagnoli and he informed us that the mean (± SD) age of the infants when EPO treatment was started was 10 ± 1 days. We therefore moved the study to the late EPO review. In addition, Dr Ohls informed us that the study by Bierer and co-workers (Bierer 2006) was a report of a subgroup of the Ohls 2001A study. It could not be ascertained from the published report that it was a duplicate publication. We therefore excluded the study by Bierer and co-workers (Bierer 2006) as all outcomes were reported in the study by Ohls 2001A.

Searches of the literature were conducted on 1 July 2013. Two new studies were identified for inclusion (Yasmeen 2012; Ohls 2013), as were two new studies for exclusion (Saeidi 2012; Costa 2013).

As expected, when two studies (Romagnoli 2000; Bierer 2006) were excluded and the results of the two new studies (Yasmeen 2012; Ohls 2013) were added almost all point estimates and confidence intervals changed.

The major difference was that the outcome of retinopathy of prematurity (ROP) stage ≥ 3 was no longer statistically significantly increased but remained of concern as the typical RR was 1.37 (95% CI 0.87 to 2.17) with no heterogeneity (I2 = 0%); the typical RD was 0.03 (95% CI -0.01 to 0.06) with low heterogeneity (I2 = 29%).

Our decision to divide the EPO studies into early and late was based on initiating EPO treatment at the cut-off of ≤ 7 days of age for early and > 7 days for late treatment with EPO. Although arbitrary, this cut-off was chosen based on previously published meta-analyses (Garcia 2002; Kotto-Kome 2004) to allow us to compare the results between our reviews and previously published reviews.

The concerns about a possible increased risk of ROP remain and because of the arbitrary cut-off age for early versus late EPO we decided post hoc to perform a secondary analysis including all studies that reported on ROP (stage ≥ 3) regardless of the age at initiation of EPO treatment. Three studies from the late EPO review were included: Al-Kharfy 1996; Romagnoli 2000; Shannon 1995. Treatment with EPO in these studies was initiated at 10 to 17 days; 10 ± 1 (SD) days; and 23 to 24 days respectively. The outcome of ROP ≥ 3 was statistically significantly increased following EPO treatment initiated at any age within the neonatal period (typical RR 1.48, 95% CI 1.02 to 2.13, P = 0.04 with no heterogeneity (I2 = 0%); typical RD 0.03, 95% CI 0.00, 0.06, P = 0.03 with moderate heterogeneity (I2 = 50%); number needed to treat to harm 33, 95% CI 17 to infinity).

When the Romagnoli 2000 study was moved to the late EPO review, the risk for ROP stage ≥ 3 was not statistically significantly increased in the late EPO review but the trend was in the direction of an increased risk (RR 1.73, 95% CI 0.92 to 3.24; RD 0.05, 95% CI -0.01 to 0.10; 3 trials enrolling 442 infants) (New Reference).

In the latest study by the Romagnoli group (Costa 2013) in which the authors compared the use of early intravenous EPO with subcutaneous EPO the incidence of stage ≥ 3 was high in both groups, 16% and 14% respectively (overall 15%), similar to the incidence of 17% in the Romagnoli 2000 study.

Thus our concerns about an increased risk of ROP ≥ 3 following EPO treatment remain.

1 July 2013New search has been performedSearches of the literature were conducted on 1 July 2013.
2 May 2012New search has been performedThis updates the review "Early erythropoietin for preventing red blood cell transfusions in preterm and/or low birth weight infants" published in the Cochrane Database of Systematic Reviews, Issue 3, 2006 (Ohlsson 2006) and updated in August 2009.
2 May 2012New citation required but conclusions have not changed

This update identified several randomised controlled studies that were excluded as they compared one EPO dosing regimen with another, did not provide the numbers randomised to the EPO and the placebo group, or the dose of EPO was not stated. A number of cohort/case-control studies reporting on a possible increased risk of ROP following treatment with EPO and ROP were identified and referenced.

The conclusions were not changed.

Studies using EPO for neuro protection will be reviewed separately (Yu 2010).

21 August 2009New search has been performed

This updates the review "Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants" published in the Cochrane Database of Systematic Reviews, Issue 3, 2006 (Ohlsson 2006).

Four additional studies (adding 145 additional infants) have been included in this review update. Studies using EPO for neuro protection are emerging.

Contributions of authors

Sanjay Aher (SA) and Arne Ohlsson (AO) contributed equally to all sections of the protocol for this review.
The literature search of databases was conducted with the help of an experienced librarian. Both review authors identified potentially eligible studies from the printouts and agreed on which trials to include. Data collection forms were designed and agreed upon by the two review authors. Quality assessments were conducted and data were abstracted by both review authors independently and compared. One review author (AO) entered the data into RevMan 5.0 and the other review author (SA) checked for accuracy. One review author (AO) wrote the sections of the full review and the other review author (SA) read and made changes. Changes were made by both review authors following feedback from the editors of the review group.

July 2009 update of the review was conducted by one author (AO).

May 2012 update of the review was conducted by one author (AO).

June 2013 update of the review was conducted by both authors (SMA and AO).

Declarations of interest

None

Sources of support

Internal sources

  • Mount Sinai Hospital, Toronto, Canada.

External sources

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Department of Health and Human Services, USA.

    Editorial support of the Cochrane Neonatal Review Group has been funded with Federal funds from the Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Department of Health and Human Services, USA, under Contract No. HHSN275201100016C.

Differences between protocol and review

In this 2013 update we included one study that used darbepoetin in one of the two treatment arms. The other arms used EPO and sham injection.

In the same update we included the results of 3 studies in a post hoc analysis of stage ≥ 3 ROP from the late EPO review (treatment initiated at ≥ 8 days) that reported on this outcome.

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Al-Kharfy 1996

MethodsA double-blind (sham-injection in the placebo group), randomized, controlled study
I. Blinding of randomization - yes
II. Blinding of intervention - yes
III. Blinding of outcome measure assessment - yes
IV. Complete follow-up - yes
Participants55 preterm infants with birth weight < 1250 g, appropriate for GA, post-natal age 10-17 days, Hct less than 0.45 and a greater than 75% probability of having BPD, determined at 10 days of age by the predictive score of Sinkin et al. were included
Infants were randomly assigned, within 250 g birth weight strata and between 10 and 17 days of age
Single centre, Canada
March 1992 to May 1994
41 infants received the 6-week treatment schedule
InterventionsInfants assigned to the treatment group (n= 27) received r-HuEPO (Eprex, Ortho Pharmaceutical, Canada Ltd), in a dosage of 200 IU/kg body weight, by sc injection, on Monday, Wednesday and Friday for 6 weeks (600 IU/kg/week; high dose)
In control infants (n=28), because of a desire to avoid repeated subcutaneous placebo injections, sham injections were given and an adhesive dressing was applied to the sham injection site. The care of the infant was then handed back to nursery personnel unaware of treatment assignment
Vitamin E (25 IU/day) and folic acid (0.05 mg/day) was commenced when enteral feeding reached 50% of total fluid intake
Oral ferrous sulphate solution was administered to the treatment group at 6 mg of elemental iron/kg/day (high dose) and the control group received 2 mg of elemental iron/kg/day
OutcomesNumber of transfusions per infant
Mortality
Sepsis
ROP (stage ≥ 3)
Hypertension
BPD (at 28 days)
NotesUnclear whether infants who had received blood transfusions prior to study entry were included or not
This study exclusively enrolled those infants, who were predicted to have >75% probability of having BPD and requiring multiple transfusions
All enrolled infants were included in the data analyses
Sham injections were given in the control group
Erythrocyte transfusions were in accordance with the guidelines developed by the Canadian Paediatric Society Fetus and Newborn Committee
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskBlinding or randomization - yes (numbered sealed envelopes)
Blinding (performance bias and detection bias)
All outcomes
Low risk

Sham-injection was given in the placebo group

Blinding of outcome measure assessment - yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskOutcomes reported on all randomized infants
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us se we could not judge if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Arif 2005

MethodsRandomised, open controlled study.
I. Blinding of randomization - can't tell
II. Blinding of intervention - no
III. Blinding of outcome measure assessment - no
IV. Complete follow-up - yes
Participants292 preterm infants < 33 weeks GA, birth weight < 1500 g, no blood sampling > 10 ml in the first 7 days after birth, not having previous blood transfusion, no IVH > grade 1, no history of haematological disease, no urinary tract infection or sepsis
Single-centre study performed in Istanbul, Turkey
Study period 1993 to 2002
Interventions142 infants in EPO group received EPO (EPREX 2000, Santa-Farma-Gurel, Istanbul) 200 IU/kg sc from the 7th day of life and continued twice weekly (400 IU/kg/week, low dose) for 6 weeks. 150 infants in the control group did not receive a placebo. Both groups received iron (3-5 mg/kg/day orally) (high dose)
OutcomesUse of one or more red blood cell transfusions, mortality, NEC, ROP (stage not reported), BP
NotesInfants who had received red blood cell transfusion prior to study entry were excluded
Transfusion guidelines were in place
The iron dose varied from 3-5 mg/kg/day but we included this as a high dose in our subgroup analyses
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskComputer-assisted randomization scheme
Allocation concealment (selection bias)Unclear riskNo information provided
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measure assessment: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Avent 2002

MethodsRandomised, open controlled study
I. Blinding of randomization - can't tell
II. Blinding of intervention - no
III. Blinding of outcome measure assessment - no
IV. Complete follow-up - yes
Participants93 infants < 7 days of life, in room air or requiring 30% oxygen at study entry with birth weight between 900 and 1500 g
Infants were stratified by weight <1250 g and >1250 g and then randomized to three treatment groups
Two centres in South Africa
Study period not stated
Interventions32 infants (low dose group) received EPO (Recormon) sc, 250 IU/kg, three times a week (high dose)
31 infants (high dose group) received EPO (Recormon) sc, 400 IU/kg three times a week (high dose)
30 infants (control group) received standard care
The endpoint of therapy was reached when the infant was discharged from the hospital
All infants received a therapeutic dose of 6 mg/kg (high dose) elemental iron orally every day, it was increased to 8-10 mg/kg (high dose iron) if the hypochromic cells became 20 per cent or more
All infants subsequently received blood transfusions if they met the transfusion criteria
OutcomesUse of one or more red blood cell transfusions
Total volume (ml/kg) of blood transfused per infant
Number of blood transfusions per infant
Mortality
Sepsis
Hypertension
Length of hospital stay
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included. Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Unclear riskBlinding of randomization: unclear
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measure assessment: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Carnielli 1992

MethodsRandomised controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes
Participants22 preterm infants with gestational age < 32 weeks and birth weight <1750 g and age >2 days
Single centre Italy
Study period not stated
Interventions11 infants in the EPO group received EPO unnamed product), 400 IU, three times weekly, iv (400 IU/ml saline solution for 1 to 2 minutes) if iv line in place (1200 IU/kg/week, high dose) and then continued sc, plus iron (h) 20 mg/kg once a week iv (high dose iron) from second day of life until discharge
11 infants in the control group did not receive either EPO or iron
OutcomesNumber of transfusions
Number of donor exposures (range)
Mortality
Neutropenia
Hospital stay in days
Side effects
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Unclear riskInfants were randomly assigned
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Carnielli 1998

MethodsRandomised controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes
Participants63 preterm infants with birth weight < 1750 g and gestational age < 32 weeks, between the second day to 8 weeks of life
Single centre, Italy
Study period not stated
Interventions22 infants in EPO + iron group received 400 IU EPO (Eprex, Cilag, Italy) per kg three times a week (high dose) + 20 mg/kg/week of iv iron (high dose)
20 infants in EPO group received EPO, 400 IU/kg three times a week (high dose) without iron (low dose)
21 infants in the control group received no treatment or placebo
Treatment was continued to the eighth week of life (or hospital discharge)
EPO was administered iv if the patient had an iv line and then continued sc at the same dose
All infants were fed the same preterm formula and they received 80 mcg/kg of folic acid and 25 IU/day of vitamin E during the study period. No oral iron supplements were given during the study period
OutcomesMean number of blood transfusions (95% CI)
BPD (age not stated)
IVH (grade not stated)
Sepsis
ROP (stage not stated)
Days in hospital
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Unclear riskInfants were randomly allocated
Blinding (performance bias and detection bias)
All outcomes
High riskBlinding of intervention: no
Blinding of outcome measurement: no
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Chang 1998

MethodsRandomised controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes
Participants45 preterm infants with BW ≤ 1800 g and GA ≤ 35 weeks, age 1 day
Single centre, China
Study period March 1996 - March 1998
Interventions15 infants in group 1 received EPO (Kirin Brewery, Co., Ltd., Japan) 150 IU/kg (450 IU/kg/week, low dose), sc, three times a week for 6 weeks
15 infants in group 2 received EPO 250 IU/kg (750 IU/kg/week, high dose), sc, three times a week for 6 weeks
15 infants in group 3 did not receive any treatment
All infants received oral iron 20 mg (high dose) from day 7 after birth
OutcomesUse of one or more red blood cell transfusions
Sepsis
Neutropenia
Hypertension
Side effects
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
It is not stated whether transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskUnclear
Allocation concealment (selection bias)Unclear riskBlinding of randomization: unclear
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Fauchère 2008

MethodsRandomised controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants

45 preterm infants born between 24 6/7 and 31 6/7 weeks

Single centre, Switzerland

Study period September 2005 through November 2006.

Interventions30 infants in the EPO group received 3000 IU rhEpo/kg (Epoietin Beta, Roche, Basel Switzerland) iv 3 to 6, 12 to 18, and 36 to 42 hours after birth. No infant was treated later with rhEpo for anaemia of prematurity. 15 infants in the placebo group received the same volume of 0.9% NaCl (indistinguishable from rhEpo). Use of iron not mentioned
OutcomesMortality, IVH (all grades and grades III-IV), Persisting periventricular echodensity, ROP (all stages and stages 3-4), Sepsis, NEC (stage not reported), BPD at 36 weeks PMA
NotesThe study was supported by Roche Foundation for Anemia Research
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskComputer-based random-number generator
Allocation concealment (selection bias)Low riskAssignment was by the hospital pharmacy
Blinding (performance bias and detection bias)
All outcomes
Low riskStudy drug and the placebo were indistinguishable
Incomplete outcome data (attrition bias)
All outcomes
Low riskOutcomes reported for all randomized infants
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Haiden 2005

MethodsRandomised controlled trial
I Blinding of randomization - yes (sealed envelopes)
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes (see notes)
Participants40 preterm infants with BW < 800 g and GA < 32 weeks
Neonatal intensive care units in Vienna, Austria
Study period October 2000 - November 2002
InterventionsThe EPO group (n = 21) received 300 IU/kg/day of EPO (Erypo, Janssen-Cilag Pharma, Vienna, Austria) iv (as long as iv access was available), or 700 IU/kg 3 times/week (2100 IU/kg/week, high dose) and iron dextran 1.5 mg/kg/day iv or iron polymerase complex 9 mg/kg/day orally (high dose)
Therapy was given until 40 weeks GA or discharge
The control group (n = 19) did not receive iv iron. Iron was started orally from the 15 th day of life or when infant tolerated 60 ml/kg of enteral feeding, which ever came first
Placebo was not used
OutcomesUse of one or more red blood cell transfusions, number of donors, mortality, NEC, PVL, IVH (grade I - II), IVH grade III - IV), hospital stay, BPD (age not stated), ROP (stage I - II), ROP (stage III - IV)
Notes47 infants were eligible for enrolment in the study. Four infants were excluded because of parental refusal (n = 2) or IVH grade IV (n = 2)
Three infants died before randomization
The final cohort included 40 infants
It is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskSealed envelopes
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskComplete follow-up: 47 infants were eligible for enrolment in the study. Four infants were excluded because of parental refusal (n = 2) or IVH grade IV (n = 2)
Three infants died before randomization
The final cohort included 40 infants
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

He 2008

MethodsRandomised controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - can't tell
III Blinding of outcome measurement - can't tell
IV Complete follow-up - can't tell
ParticipantsPopulation: 44 preterm infants, 7 days old
InterventionsIntervention: The EPO group received 250 IU/kg/day 3 times weekly iv for 4 weeks (750 IU/kg/week, high dose). The use of iron is not stated nor is it stated what the control group received
OutcomesNeonatal Behavioral Neurological Assessment at 40 weeks PMA, and Gesell Developmental Schedule at 6 and 12 months after birth
NotesThis study has been published as a full report in Chinese. Only the abstract was written in English. We have requested the full paper and if possible an English translation from the first author (2009 08 08). The only data provided with means and SD were for the Neonatal Behavioral Neurological Assessment at 40 weeks PMA
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Unclear risk44 preterm infants were randomly divided into two groups
Blinding (performance bias and detection bias)
All outcomes
Unclear risk

Blinding of intervention: unclear

Blinding of outcome measurement: unclear

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskComplete follow-up: unclear
Selective reporting (reporting bias)Unclear riskAs we have not been able to obtain an English translation of the full article this item cannot be assessed
Other biasUnclear riskAs we have not been able to obtain an English translation of the full article this item cannot be assessed

Khatami 2008

MethodsRandomised controlled trial
I Blinding of randomization - yes, sealed envelopes
II Blinding of intervention - no, a placebo was not used
III Blinding of outcome measurement - no
IV Complete follow-up - yes
ParticipantsPopulation: 40 preterm infants with BW > 1000 g but < 1750 g and GA > 28 weeks but < 34 weeks, and were between 48 and 96 hours old at the time of entering the study
InterventionsThe EPO group received 500 IU/kg/day of EPO sc twice weekly (1000 IU/kg/week, high dose) and iron (ferrous sulphate) 3mg/kg/day enterally (low dose). Control infants received iron (ferrous sulphate) 3mg/kg/day enterally (low dose) at second week of life. Parenteral iron was not administered throughout the study
OutcomesNumber of red blood cell transfusions per patient, weight gain, hospital stay
Notes"Guidelines for red-cell transfusions were based on the relatively strict existing policy in the nursery which was used to administer transfusions during the study period"
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskNumbered sealed envelopes
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no, a placebo was not used

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes. 18 infants were excluded due to parents' refusal and unavailability
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Lauterbach 1995

MethodsRandomised controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - can't tell
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants19 preterm infants with GA < 35 weeks and birthweight ≤ 1500 g
Single centre study conducted in Poland
InterventionsInfants in EPO group I (n = 6) received EPO (Recormon, Boehringer Mannheim) 100 IU/kg twice a week iv (200 IU/kg/week, low dose) between days 7 and 37, and infants in EPO group II (n = 6) received 400 IU/kg twice weekly (800 IU/kg/week, high dose) during the same time period. The control group (n = 7) received no treatment or placebo. Both EPO groups received 10 mg/kg/week of iron iv (high dose). The control group did not receive iron
OutcomesTotal volume (ml/kg) of blood transfused between days 7 and 37
Side effects
NotesTransfusion guide lines were in place
We could not ascertain whether infants who had received blood transfusions prior to study entry were included
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Unclear riskRandomly selected preterm infants
Blinding (performance bias and detection bias)
All outcomes
Unclear risk

Blinding of intervention: no

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Lima-Rogel 1998

MethodsDouble blind, randomized controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants40 VLBW infants with birth weight between 750 and 1500 g and gestation age < 26 weeks
Single centre, Mexico
Study period: 1995 to 1996
Interventions21 infants in the EPO group received EPO (Eprex 4000, Cilag de Mexico SA de CV) 150 units/kg/day (during the first 6 weeks of life), 1050 IU/kg/week (high dose) and 19 infants in the control group received placebo
Iron 4 mg/kg/day (low dose)
OutcomesNumber of transfusions per group
Sepsis
NEC
IVH (grade not reported)
BPD (age not stated)
NotesWe could not ascertain whether transfusion guide lines were in place and if infants who had received blood transfusions prior to study entry were included
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskUnclear
Allocation concealment (selection bias)Unclear riskInfants were randomly assigned
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Maier 1994

MethodsDouble blind, randomized controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - no?, see notes
Participants244 infants with birth weight of 750 to 1499 g, 3 infants were excluded after randomization
12 centres in six European countries
September 1991 to December 1992
Interventions120 infants in the EPO group received 250 IU of epoetin beta (Boehringer-Mannheim, Germany) per kilogram, injections on Monday, Wednesday and Friday (750 IU/kg/week, high dose). The treatment continued until day 40 to 42, for a total of 17 doses
121 infants in the control group did not receive placebo but adhesive tape was placed on both thighs, which remained there until next visit
Oral iron supplementation, 2 mg/kg/day was started on day 14 in all infants (low dose)
Vitamin E supplementation was not part of the protocol
OutcomesUse of one or more red blood cell transfusions
Number of transfusions per infant
Mortality
ROP
Sepsis
NEC
IVH all grades
IVH grades III-IV
Neutropenia
Hypertension
Side effects
NotesInfants who had received transfusions prior to study entry were included (28 in the EPO group and 17 in the control group)
Transfusion guidelines were in place
33 infants were withdrawn in the EPO group and 28 in the control group
The results are reported as per ITT
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskNumbered sealed envelopes
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
High risk

Complete follow-up: no
33 infants were withdrawn in the EPO group and 28 in the control group
The results are reported as per ITT

Three of the 244 infants who underwent randomization were excluded; all data on two infants were lost, and treatment (EPO) was inadvertently omitted in one infant, whose records were not completed. The remaining 241 infants were evaluated in an intention-to-treat analysis

Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Maier 2002

MethodsDouble blind, randomized controlled trial
I Blinding of randomization - yes (sealed envelopes)
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants219 ELBW infants were randomly assigned to early EPO, a late EPO or control group on day 3 of life
14 enters in 4 European countries
May 1998 to June 1999
Interventions74 infants in the early EPO group received EPO (NeoRecor-mon, F. Hoffman-La Roche, Basel, Switzerland) 250 IU/kg, iv or sc, three times a week (750 IU/kg/week, high dose) starting from day 3 of life, for 9 weeks
74 infants in late EPO group received EPO 250 IU/kg iv or sc, three times a week starting from the fourth week of life, for 6 weeks
71 infants in the control group received sham injections
Enteral iron 3 mg/kg was given to all infants from days 3 to 5 and was increased at days 12 to 14 to 6 mg/kg/day and to 9 mg/kg/day at days 24 to 26 of life (high dose)
OutcomesUse of one or more red blood cell transfusions
Number of donors the infant was exposed to (median, quartiles)
Number of transfusions per infant (mean)
Mortality during hospital stay
NEC
IVH (grade not stated)
PVL
ROP (stage not stated)
BPD (at 36 weeks postmenstrual age)
Growth
Days in hospital (median, quartiles)
NotesSample size calculation was performed
24 (32%) of the infants in the early EPO group and 22 (31%) in the control group were exposed to donor blood before they entered the study
Transfusion guidelines were followed
Industry funded (F Hoffman-La Roche, Basel Switzerland)
One infant was excluded from all evaluations because the parents withdrew consent a few hours after randomization before the start of the treatment phase
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskNumbered, sealed envelopes
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes - When treatment was to be given, a dosing investigator carrying a "black box" containing appropriate equipment visited each infant, gave or simulated administration of the study medication, and placed adhesive strips on both thighs (of EPO recipients and controls)

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes; One of the 220 randomized infants (control group) was excluded from all evaluations because the parents withdrew consent a few hours after randomization before the start of treatment phase
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Meister 1997

MethodsRandomised controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes (see notes)
Participants30 preterm infants with birth weight of 750 to 1499 g and five to 10 days old
Single centre, Austria
Study period not stated
Interventions15 infants in the EPO group received epoetin alpha (Janssen-Cilag Pharmaceuticals, Vienna, Austria) 300 IU/kg sc 3 times a week for 4 weeks
15 infants in the control group did not receive the drug
Oral iron administration was started with a dose of 6 mg/kg/day and increased after two weeks to 8 mg/kg/day. The control group patients received iron alone
OutcomesStudy gives results as cumulative volume of blood transfused per kg with first and third quartiles
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
One infant in the control group was withdrawn from the study because of development of IVH grade IV
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskComputerised random numbers generator
Allocation concealment (selection bias)Unclear riskThirty preterm infants were randomly assigned
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
One infant in the control group was withdrawn from the study because of development of IVH grade IV
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Meyer 2003

MethodsDouble blind, randomized controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants43 preterm infants < 33 weeks gestation and < 1700 g
Single centre, Auckland, New Zealand
Two year period 1995-1996
Interventions22 infants in EPO group received erythropoietin (Eprex; Janssen-Cilag, Auckland, New Zealand) at a dose of 1200 IU/kg/week (high dose) sc in three divided doses until the age of 3 weeks when the dose was reduced to 600 IU/kg/week. Treatment continued until 34 weeks completed gestation or for a minimum of three weeks
21 infants in the control group received sham treatment, to avoid sc injection
Ferrous gluconate at a dose of 6 mg of elemental iron/kg/day (high dose) was given to the EPO group once they had attained a postnatal age of 2 weeks and receiving at least 50% energy intake orally. Those in the control group received 2 mg/kg/day iron from the same age in a more dilute preparation so that an equivalent volume was given
All infants received a multivitamin preparation and vitamin E (25 IU/day)
OutcomesUse of one or more red blood cell transfusions
Number of donors the infant was exposed to
Number of transfusions per infant
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskComputer-generated
Allocation concealment (selection bias)Low riskInfants were randomized by the hospital pharmacist to receive either EPO or no treatment (control group)
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes - infants randomized to the control group received sham treatment, to avoid subcutaneous placebo injections Treatment was administered by a designated nurse not involved in clinical management decisions relating to the infants

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Obladen 1991

MethodsRandomised controlled trial
I Blinding of randomization - yes (sealed envelopes)
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes
Participants93 infants with gestational age of 28-32 completed weeks
Five centres, Europe
April 1989 to February 1990
Interventions43 infants in the EPO group received EPO (Boehringer Mannheim GmbH) 30 IU/kg sc every 3rd day (70 IU/kg/week, low dose) from the 4th to 25 th day of life
50 control infants did not receive sc injections of placebo, but were managed identically
Elemental iron treatment was started on day 14 with 2 mg/day orally
OutcomesUse of one or more red blood cell transfusions
Total volume of blood transfused per infant
Mortality
Chronic lung disease
ROP ( infants were followed for ROP, but results not reported)
IVH
NEC
BPD
Hypertension
Renal failure
PDA
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskPrenumbered sealed envelopes
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Ohls 1995

MethodsRandomised controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants20 ill newborn VLBW infants, less than 48 hours of age, weight between 750 and 1500 g at birth and GA >27 weeks
Single centre, USA
Study period not stated
Interventions10 infants in the EPO group received EPO (unnamed product), 200 IU/kg/day (1400 IU/kg/week, high dose) iv for 14 consecutive days
10 infants in the control group received similar volume of 0.9% saline solution in similar fashion as placebo
Infants in both groups received iron, 2 mg/kg per day orally, when they were taking 70 ml/kg/day enterally, which was increased to 6 mg/kg per day (high dose) when the infants were receiving more than 100 ml/kg per day of feeds
OutcomesUse of one or more red blood cell transfusions
Total volume of blood transfused per infant
Number of transfusions per infant
BPD
Neutropenia
NEC
IVH
Side effects
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Unclear riskInfants were randomly selected
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low risk

Complete follow-up: yes

There were no differences in the number of infants with BPD, IVH, or NEC (data not shown)

Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol. After the interim analysis, the study was discontinued because of significant differences between groups in number of transfusions
Other biasLow riskAppears free of other bias

Ohls 1997

MethodsDouble blind, randomized controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants28 ELBW infants with birth weight 750 g or less and were 72 hours of age or younger
3 enters, USA
Period not stated
Interventions15 infants received EPO (unnamed product) 200 IU/kg/day (1400 IU/kg/day, high dose) iv, for 14 consecutive days
13 infants received placebo as an equivalent volume of diluent in similar fashion
All infants received 1 mg/kg/day iron dextran in TPN solution during treatment period (high dose)
All infants received vitamin E, 25 IU/day when they tolerated 60 ml/kg/day feeds enterally
OutcomesTotal volume of blood transfused per infant
Number of transfusions per infant
Mortality
Sepsis
IVH
BPD
ROP
Neutropenia
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskInfants were randomly assigned in a double-blind fashion
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes. Two infants in each group died before the 21-day study period
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Ohls 2001A

MethodsDouble blind, randomized controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants172 infants with birth weight between 401 g to 1000 g, gestational age < 32 weeks and between 24 and 96 hours old at the time of study entry and were likely to survive > 72 hours
Multicentre trial, USA
Trial period not stated
Interventions87 infants in the EPO group received 400 U/kg EPO (unnamed product) 3 times weekly (1200 IU/kg/week, high dose) iv or sc when iv access was not available
85 infants in the placebo/control group received sham sc injections when iv access was not available. An adhesive bandage covered the true and sham injection sites. Treatment was continued until discharge, transfer, death or 35 completed weeks corrected GA
Treated infants received a weekly iv infusion of 5 mg/kg iron dextran (high dose) until they had an enteral intake of 60 ml/kg/day. Iron dextran was either added to the TPN solution and administered over 24 hours or diluted in 10% dextrose in water or normal saline and administered over 4 to 6 hours. Placebo/control infants received 1 mg/kg iron dextran once a week, administered in a similar manner. Once infants in both groups had enteral intake of 60 mg/kg/day, they were given iron at a dose of 3 mg/kg/day. The dose was gradually increased to 6 mg/kg/day depending on enteral intake
Study infants received enteral vitamin E 15-25 IU/day and enteral folate supplements 25-50 mcg/day were provided according to centre practice
OutcomesUse of one or more red blood cell transfusions
Mean number of erythrocyte transfusions per infant
Number of donors the infant was exposed to
Total volume of blood transfused per infant
Late onset sepsis
Mortality
Chronic lung disease (at 36 weeks postmenstrual age)
ROP
Severe IVH (stage ≥ 3)
NEC
BPD
Neutropenia
Hypertension
Hospital stay
At follow-up (see notes) growth, development, re-hospitalization, transfusions
Notes

It is not stated whether infants who had received blood transfusions prior to study entry were included
Strict protocol was used to administer transfusions during study period
Of the 72 EPO treated and 70 placebo-control infants surviving to discharge follow-up data at 18 to 22 months' corrected age were collected on 51 of 72 EPO-treated infants (71%) and 51 of 70 placebo/controls (73%)

The study was supported by grants from Ortho-Biotech and Schein Pharmaceuticals

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskBlinding of randomization: yes - All caregivers and investigators (except the research nurses) were masked to the treatment assignment
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskAll infants were followed through their hospital stay up to 120 days
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Ohls 2001B

MethodsDouble blind, randomized controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants118 infants with birth weight between 1001 g to 1250 g, gestational age < 32 weeks and between 24 and 96 hours old at the time of study entry and were likely to survive > 72 hours
Multicenter trial, USA
Trial period not stated
Interventions59 infants in the EPO group received 400 IU/kg EPO (unnamed product) 3 times weekly (1200 IU/kg/week, high dose) iv or sc when iv access was not available
59 infants in the placebo/control group received sham sc injections when iv access was not available. An adhesive bandage covered the true and sham injection sites. Treatment was continued until discharge, transfer, death or 35 completed weeks PMA
Treated infants received a weekly iv infusion of 5 mg/kg iron dextran (high dose) until they had an enteral intake of 60 ml/kg/day. Iron dextran was either added to the TPN solution and administered over 24 hours or diluted in 10% dextrose in water or normal saline and administered over 4 to 6 hours. Placebo/control infants received 1 mg/kg iron dextran once a week, administered in a similar manner. Once infants in both groups had enteral intake of 60 mg/kg/day, they were given iron at a dose of 3 mg/kg/day. The dose was gradually increased to 6 mg/kg/day depending on enteral intake
Study infants received enteral vitamin E 15-25 IU/day and enteral folate supplements 25-50 mcg/day were provided according to centre practice
OutcomesUse of one or more red blood cell transfusions
Mean number of erythrocyte transfusions per infant
Number of donors the infant was exposed to
Total volume of blood transfused per infant
Late onset sepsis
Mortality
Chronic lung disease
ROP
Severe IVH
NEC
BPD (at 36 weeks postmenstrual age)
Neutropenia
Hypertension
Length of hospital stay
Notes

It is not stated whether infants who had received blood transfusions prior to study entry were included
Strict protocol was used to administer transfusions during study period

The study was supported by grants from Ortho-Biotech and Schein Pharmaceuticals

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided
Allocation concealment (selection bias)Low riskBlinding of randomization: yes
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes - all caregivers and investigators (except the research nurses) were masked to the treatment assignment

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskAll infants were followed through their hospital stay up to 120 days
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Ohls 2013

MethodsRandomised, masked, controlled clinical trial
I. Blinding of randomization - yes
II. Blinding of intervention - yes
III. Blinding of outcome - measure assessment- yes
IV. Complete follow-up - yes
Participants102 infants with BW 500 to 1250 g and ≤ 48 hours of age. Study period: July 2006 to May 2010
InterventionsInfants were randomized in masked fashion to 1 of 3 groups: EPO, 400 U/kg, given subcutaneously 3 times a week (Monday, Wednesday, and Friday); Darbe, 10 µg/kg, given subcutaneously once a week, with sham dosing 2 other times per week; or placebo, consisting of 3 sham doses per week. Dosing continued until 35 completed weeks’ gestation, discharge, transfer to another hospital, or death. Doses of Darbe and EPO were initially based on study entry weight and adjusted weekly. Study drug concentrations were chosen to give equivalent volumes (0.1 mL/kg body weight) of Darbe or EPO. All infants (regardless of treatment arm) received supplemental iron, folate (50 mg per day oral), and vitamin E
(15 IU per day oral). Iron dextran, 3 mg/kg once a week was added to parenteral nutrition while infants were receiving, 60 mL/kg per day enteral feedings. Oral iron 3 mg/kg per day was started when feedings were ≥60mL/kg per day, and increased to 6 mg/kg per day when feedings reached 120 mL/kg per day (high dose). Serum ferritin concentrations were used to adjust iron dosing. For infants in whom ferritin concentrations were >400 ng/mL, the parenteral or enteral dose of iron was decreased by 50%; for infants in whom ferritin concentrations were <50 ng/mL, the parenteral or enteral dose was doubled
OutcomesUse of one or more red blood cell transfusions, total volume (mL/kg) of blood transfused per infant, number of blood transfusions per infant, number of donors the infant was exposed to, mortality during initial hospital stay, ROP all stages and stages ≥ 3, late onset sepsis, NEC stage > 2, IVH grade ≥ 3, PVL, length of hospital stay, BPD (oxygen dependency at 36 weeks PMA), neutropenia and hypertension. Cognitive scores on Bayley Scales of Infant Development (BSID-III) at 18-22 months were reported in abstract form
NotesWe obtained additional information from Dr Ohls regarding several outcomes, which explains why some of the data we have entered in RevMan5.2 differ from the original publication. 17 infants (17%) were transfused prior to initiation of treatment
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskThe randomization lists for each pharmacist were computer generated.
Allocation concealment (selection bias)Low riskAll caregivers were blinded to the treatment groups except the research pharmacists at each site, who drew up the study medications to be administered by the research nurse.
Blinding (performance bias and detection bias)
All outcomes
Low riskInfants were randomized in masked fashion to 1 of 3 groups: EPO, 400 U/kg, given subcutaneously 3 times a week (Monday, Wednesday, and Friday) (high dose); Darbe, 10 µg/kg, given subcutaneously once a week, with sham dosing 2 other times per week; or placebo, consisting of 3 sham doses per week. The study drug was brought to the bedside in a closed container, and injections were shielded behind screens and out of earshot from caregivers and parents. An adhesive bandage covered the true and sham injection sites. Dosing continued until 35 completed weeks’ gestation, discharge, transfer to another hospital, or death. Doses of Darbe and EPO were initially based on study entry weight and adjusted weekly. Study drug concentrations were chosen to give equivalent volumes (0.1 mL/kg body weight) of Darbe or EPO
Incomplete outcome data (attrition bias)
All outcomes
Low riskThree subjects (one who had the study drug mistakenly held at the start of the study and subsequently never received any study drug; one who was found to be ineligible based on congenital neurologic anomaly on head ultrasound noted before receiving study drug and one who died of a pulmonary haemorrhage before receiving study drug) were excluded from analysis. One infant had the study drug stopped at 34 weeks’ corrected gestation at the request of parents. All infants who received at least 1 dose of study drug were included in analysis (n = 33 in each group)
Selective reporting (reporting bias)Low riskThe study was registered as NCT00334737 in June 2006. There does not seem to be any major deviations from the protocol except that the primary outcomes included MDI at 18-22 months and PDI as a secondary outcome. MDI and PDI are not reported in the primary publication. Bayley Scales of Infant Development (BSID-III) cognitive scores at 18-22 months are reported in E-PAS2013:2924 but not the PDI scores. 14 infants were lost to follow-up
Other biasLow riskAppears free of other bias

Romagnoli 2000

MethodsRandomised, double-blind, controlled clinical trial
I. Blinding of randomization - yes (sealed envelopes, on the 7th day of life)
II. Blinding of intervention - no
III. Blinding of outcome-measure assessment - no (ROP was)
IV. Complete follow-up - yes
Participants230 infants with gestational age < 30 weeks and 31-34 weeks with RDS and requiring mechanical ventilation, mean (SD) age at initiation of treatment 10 ± 1 days
Single centre, Rome
3 year period ending December 1998
Interventions115 infants received EPO (unnamed product) 300 IU/kg sc, three times a week (900 IU/kg/week, high dose) from the 2nd to the 7th week and iron 1 mg/kg/day iv (high dose)
115 infants did not receive EPO, placebo or iron
OutcomesUse of one or more red blood cell transfusions
Number of blood transfusions per infant
ROP
NEC
IVH grade ≥ III - IV
Chronic lung disease at 28 days
Sepsis
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Protocol was used to administer transfusions during study period. For the 2013 update of the review this study was moved to the late EPO review. All outcomes from this study were deleted except for the outcome of ROP (stages ≥ 3), which is reported in one secondary analysis included in this update
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandom number
Allocation concealment (selection bias)Low riskOpening of numbered, sealed envelopes, on the 7th day of life
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome-measure assessment: no (the outcome of ROP was)

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol. This study was reported as a "Research letter" format allowing for a limited number of details
Other biasUnclear riskThis study was reported in a "Research letter" format allowing only for few details

Salvado 2000

MethodsRandomised, double-blind, controlled clinical trial
I. Blinding of randomization - yes
II. Blinding of intervention - yes
III. Blinding of outcome - measure assessment - yes
IV. Complete follow-up - yes
Participants60 newborn infants under 1500 g birth weight; mean age at entry in the EPO group 7.75 ± 2.42 days and mean age at entry in the control group 7.96 ± 2.44 days
Single centre, Chile
April 1998 to December 1999
Interventions29 infants in the EPO group received r-EPO (eritropoyetina del Laboraorio Andromaco) 200 IU/kg sc, 3 times a week (600 IU/kg/week, high dose), during 4 weeks
31 infants in the control group received similar volume of isotonic saline solution in similar fashion
All infants received oral iron at a dose of 3 mg/kg/day (low dose)
OutcomesNumber of transfusions per infant
Sepsis
IVH
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information presented
Allocation concealment (selection bias)Low riskBlinding of randomization: yes
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes

Blinding of outcome measure assessment: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Shannon 1995

MethodsMulti-centre, randomized, double-blind, controlled clinical trial
I. Blinding of randomization - yes
II. Blinding of intervention - yes
IV. Blinding of outcome-measure assessment - yes
IV. Complete follow-up - yes
Participants157 preterm infants with GA <31 weeks with birth weight ≤ 1250 g
Mean (SD) age (days) at study entry; EPO group 22.9±10.1; Placebo group 24.1±9.9
Multi-centre study, 11 centres, USA
October 1991 to October 1993
InterventionsSC injection of rHuEPO at a dose of 100 IU/kg, or an identical volume of placebo suspension, were given from Monday through Friday (500 IU/kg/week; high dose) for 6 weeks or until the infants were ready to be discharged home. Doses of rHuEPO (or placebo) were adjusted weekly according to changes in body weight
There were 77 infants in the rHuEPO group and 80 infants in the placebo group
Patients received oral iron supplements at study entry to achieve a total enteral intake of 3 mg/kg/day of elemental iron (low dose)
Total iron intake was increased to 6 mg/kg/day when the infants tolerated full caloric feeding enterally
Infants also received 15 IU of supplemental vitamin E and an additional 1 mL/day of an enteral multivitamin preparation
OutcomesExposure of a proportion of infants to one or more red blood cell transfusions
Mean number of erythrocyte transfusions per infant
Mortality
Sepsis
NEC
ROP
Hypertension
SIDS
Side effects
NotesInfants who had received blood transfusions prior to study entry were included
Guidelines for blood transfusions were developed
This study reports four post-discharge infants deaths among 125 infants followed until they were at least 6 months old. Three placebo treated infants died; 2 of probable SIDS and one from aspiration pneumonia
The only late infant death in an EPO treated infant occurred at 11 month of age from late NEC
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskComputer-generated randomization was used
Allocation concealment (selection bias)Low riskThe personnel responsible for administration of support, oversight, and monitoring of the study, the study chair and all investigators were masked to treatment group assignments throughout the study
Blinding (performance bias and detection bias)
All outcomes
Low riskA placebo was used
Incomplete outcome data (attrition bias)
All outcomes
Low riskOutcomes reported for all infants randomized
Selective reporting (reporting bias)Unclear riskThe study was not entered into a trials registry and we cannot tell if there were any deviations from the study protocol
Other biasLow riskAppears free of other bias

Soubasi 1993

MethodsRandomised, double-blind, controlled trial
I Blinding of randomization - yes
II Blinding of intervention - yes
III Blinding of outcome measurement - yes
IV Complete follow-up - yes
Participants44 newborn infants with birth weight under 1500 g, age 1-7 days
Single centre trial conducted in Thessaloniki Greece
Period not stated
InterventionsThe EPO group (n = 25) received 150 IU/kg/dose of EPO (Cilag AG, Zug, Switzerland) twice a week (300 IU/kg/week, low dose) during 4 weeks. The control group (n = 19) received a placebo. From the 15 th day of life iron was started at 3 mg/kg/day (low dose) in all infants
OutcomesNumber of transfusions per infant, sepsis, IVH and days on ventilator
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandom number table
Allocation concealment (selection bias)Low riskBlinding of randomization: yes
Blinding (performance bias and detection bias)
All outcomes
Low risk

Blinding of intervention: yes - "doctors in clinical charge were unaware of the treatment or control status of the babies"

Blinding of outcome measurement: yes

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Soubasi 1995

MethodsRandomised controlled trial
I Blinding of randomization - can't tell
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes
Participants97 VLBW infants with GA 31 weeks or less, birth weight 1500 g or less and age 1 to 7 days
Single centre, Greece
Period not stated
Interventions33 infants received rHuEPO (Cilag AG, Zug, Switzerland) 150 IU/kg twice weekly (300 IU/kg/week, low dose)
28 infants received rHuEPO 250 U/kg three times per week (750 IU/kg/week, high dose)
EPO was administered from the fist week of life for 6 weeks
36 infants (control) did not receive any treatment
All infants received oral elemental iron, 3 mg/kg/day from day 15 of life (low dose)
75 infants were followed, after discontinuation of EPO therapy, weekly until discharge and thereafter at 3, 6 and 12 months of age
OutcomesUse of one or more red blood cell transfusions
Number of blood transfusions per infant
Mortality
Follow-up to one year of age
Hospital stay
75 infants were followed, after discontinuation of EPO therapy, weekly until discharge and thereafter at 3, 6 and 12 months of age (no neurodevelopmental outcomes reported)
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandom-number table
Allocation concealment (selection bias)Unclear riskThe infants were randomly assigned
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measurement: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppear free of other bias

Soubasi 2000

MethodsRandomised, controlled clinical trial
I. Blinding of randomization - can't tell
II. Blinding of intervention - no?
III. Blinding of outcome-measure assessment - no
IV. Completeness follow-up - yes
Participants36 very low birth weight infants with gestational age < 31 weeks and birth weight < 1300 g with clinical stability at the time of entry
Single centre, Thessaloniki, Greece
Study period not stated
Interventions18 infants in the treatment group received rHuEPO (Cilag AG, Zug, Switzerland) 200 IU/kg every alternate day (700 units/kg/week, high dose) sc
18 infants in the control group did not receive EPO or placebo
Duration of EPO treatment not stated
Additionally, infants received oral iron at a dose of 12 mg/kg/day (high dose) in the EPO group and 4 mg/kg/day in the control group
Both groups were supplemented with 500 mcg of oral folate every other day, 10 IU of vitamin E every day and multivitamins, when enteral feeding reached 75% of total fluid intake, until discharge
OutcomesUse of one or more red blood cell transfusions
Number of transfusions per infant
NotesThis study does not mention the exact day when treatment was started
It is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandom-number table
Allocation concealment (selection bias)Unclear riskInfants were randomly assigned
Blinding (performance bias and detection bias)
All outcomes
High risk

Blinding of intervention: no

Blinding of outcome measure assessment: no

Incomplete outcome data (attrition bias)
All outcomes
Low riskCompleteness follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Yasmeen 2012

MethodsRandomised controlled trial
I Blinding of randomization - yes
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes
Participants

60 VLBW infants, < 7 days of age, < 35 weeks PMA and < 1500 g weight

Single centre, Dhaka, Bangladesh

April 2007 to May 2008

Interventions30 infants were supplemented with rHuEPO 200 IU/kg/dose sc three times/ week for two weeks started on day 7 of life. The EPO group as well as the control group (n = 30) received oral iron 6 mg/kg/day and folic acid 0.5 mg every alternate day up to 12 weeks of age. Both iron and folic acid administration started from day 14 of life or as soon as enteral feeding was initiated after day 14
OutcomesMortality is the only outcome that can be ascertained from this study
NotesMortality is the only outcome that can be ascertained from this study. For all the other outcomes of interest including neonates requiring blood transfusion while in hospital, the authors excluded 13 infants; in the EPO group, 4 infants died during hospital stay and 1 patient did not come in 1st follow up and 1 at 2nd follow up. In the Control group 5
infants died during hospital stay and 2 did not come in 2nd follow up. Finally 24 infants in Group I and 23 infants in Group II completed the follow up until 10 weeks of age. These 13 dropped out infants were excluded from the analysis. We suggest that the infants who died should have been included in both the nominator and the denominator for the outcome of need for blood transfusion and number of blood transfusions (intention to treat analysis. A total of 13 infants dropped out of the study which represents 22% a very high percentage
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskLottery method
Allocation concealment (selection bias)Unclear riskLottery method
Blinding (performance bias and detection bias)
All outcomes
Unclear riskThe intervention was not blinded - there was no placebo used
Incomplete outcome data (attrition bias)
All outcomes
High risk22% of the infants dropped out. In hospital outcome data did not include the deaths. Lack of intention-to-treat analysis
Selective reporting (reporting bias)Unclear riskThe protocol for this study was not available to us so we are not able to tell if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Yeo 2001

  1. a

    BP: blood pressure
    BPD: bronchopulmonary dysplasia
    BW: birth weight
    CI = confidence interval
    ELBW: extremely low birth weightEPO: erythropoietin
    GA = gestational age
    g = grams
    Hct: hematocrit
    ITT: intention-to-treat
    IU = international units
    iv = intravenous/intravenously
    IVH: intraventricular haemorrhage
    NEC: necrotising enterocolitis
    PMA: postmenstrual age
    PVL: periventricular leukomalacia
    ROP: retinopathy of prematurity
    sc = subcutaneous/subcutaneously
    TPN = total parenteral nutrition
    VLBW: very low birth weight

MethodsRandomised controlled trial
I Blinding of randomization - no
II Blinding of intervention - no
III Blinding of outcome measurement - no
IV Complete follow-up - yes
Participants100 VLBW infants, < 33 weeks GA, Hct 40-60% at birth
Single centre, Singapore
January 1997 to March 2000
Interventions50 infants in the EPO group received EPO (unnamed product) 250 IU/kg/dose sc three times a week (750 IU/kg/week, high dose) from day 5 to day 40
50 infants in the control group did not receive any treatment
Infants in both groups received elemental iron, 3 mg/kg/day orally from day 10 and increased to 6 mg/kg/day (high dose) when full feeds were well tolerated
OutcomesExposure of a proportion of infants to one or more red blood cell transfusions
Mean number of erythrocyte transfusions per infant
Total volume of blood transfused per infant
Mortality
ROP (stage not stated)
Sepsis
NEC
BPD (age not stated)
Hypertension
NotesIt is not stated whether infants who had received blood transfusions prior to study entry were included
Transfusion guidelines were in place
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskUnclear
Allocation concealment (selection bias)Unclear riskInfants were randomized to receive either EPO or no drug
Blinding (performance bias and detection bias)
All outcomes
High riskA non-blind randomized controlled trial
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: yes
Selective reporting (reporting bias)Unclear riskThe protocol for the study was not available to us and therefore we can not ascertain if there were deviations from the protocol
Other biasLow riskAppears free of other bias

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
  1. a

    EPO: erythropoietin
    IVH: intraventricular haemorrhage
    sc: subcutaneous

Amin 2002This study is not a randomized controlled trial
Bierer 2006One of the authors of this study, Dr RK Ohls, informed us that this study reported on a subgroup of the Ohls 2001A study. All outcomes of the Bierer 2006 are included in the 2004 follow-up publication of the Ohls 2001A study
Brown 1999This study compares two different dosing regimens for the same total weekly dose of EPO. There was no control or placebo group
Costa 2013This study assessed the effectiveness of iv vs sc administration of EPO. There was no non-treated group
Fearing 2002This study does not give the number of infants allocated to treatment and control groups or the age at which the infants were entered
Haiden 2006aThis study reports the same findings as in the study by Haiden 2005
Haiden 2006bBoth study groups received erythropoietin
Juul 2008Not a randomized controlled trial
Klipp 2007A randomized controlled trial but no clinical outcomes of interest for this review
Krallis 1999No outcomes of interest for this review were reported
Maggio 2007This randomized controlled trial compared the effectiveness of EPO administered by continuous intravenous versus subcutaneous route
Maier 1998This randomized controlled trial compared two doses of EPO; 750 IU/kg/week versus 1500 IU/kg/week without a non-treated control group
Ohls 1996The study compared different routes of administration (sc EPO versus adding EPO to the total parenteral nutrition fluid). There was no untreated control group
Saeidi 2012This was a randomized controlled trial in which one group received oral EPO and the other group sc EPO. There was no untreated control group
Soubasi 2005128 infants were randomized early (1st week of life) to EPO group (n = 66) or control group (n = 62). The dose of EPO is not stated in the abstract. Infants randomized to EPO received significantly fewer transfusions and had less IVH
Soubasi 2009Not a randomized controlled trial (20 study patients and 20 concurrent controls)
Turker 2005This study was labelled by the authors as a quasi-randomised (assignment on an alternating basis) trial. The authors reported on uneven numbers in the two groups (42 infants in the EPO group and 51 in the control group). On request the principal author provided the following information. "In the study period 112 premature infants <1500 gm were followed in the NICU. Informed consents were obtained from the parents of 97 babies, but only 93 babies completed the study because 3 patients were lost to follow-up after discharge and one baby died of bronchopulmonary dysplasia before completing the 12-week monitoring period. These 4 babies were omitted from the study group (r-Hu EPO+enteral iron). These infants are included in the result section. At the end of the study r-Hu EPO was not available, and 2 more patients had only iron supplementation. Then the study was closed and these 2 babies were also added to the control group.
97 patients (48 EPO group; 3 lost-to follow-up,1 died, -2 r-Hu Epo was unavailable; 49 controls; +2)
Based on this information we excluded the study as it was not a quasi-randomised trial
Vázquez López 2011This randomized controlled trial compared two different dosing schedules of EPO. Group 1 (60 infants; mean postnatal age at entry 6 +/- 3.1 days) received sc EPO at 250 units per kg per dose, three times weekly for six weeks. Group 2 (59 infants; mean postnatal age at entry 7 +/- 3.9 days) received sc EPO at 750 units per kg per dose once weekly for 6 weeks. There was no untreated group
Zhu 2009The population consisted of infants > 37 weeks PMA

Ancillary