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Keywords:

  • Juvenile idiopathic arthritis;
  • Adherence;
  • Health outcomes;
  • Function;
  • Quality of life

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. REFERENCES

Objective

To determine the impact of adherence to treatment (medication and prescribed exercise) on outcomes in children with juvenile idiopathic arthritis (JIA).

Methods

In this longitudinal study, we studied parents of patients with JIA at the Montreal Children's Hospital and British Columbia Children's Hospital in Vancouver. Adherence was evaluated on a visual analog scale in the Parent Adherence Report Questionnaire. Outcomes of interest were active joint count, pain, child functional score on the Child Health Assessment Questionnaire, quality of life score on the Juvenile Arthritis Quality of Life Questionnaire, and parental global impression of overall well-being. The association between adherence to treatment and subsequent outcomes was evaluated using generalized estimating equations and logistic regression.

Results

Mean age and disease duration of our sample of 175 children were 10.2 and 4.1 years, respectively. Moderate adherence to medication was associated with lower active joint count (odds ratio [OR] 0.47, 95% confidence interval [95% CI] 0.22–0.99). Moderate adherence to exercise was associated with better functional score (OR 0.13, 95% CI 0.03–0.54), and lower pain during the last week (OR 0.14, 95% CI 0.04–0.50). Both high and moderate adherence to exercise were associated with parental perception of global improvement.

Conclusion

Improved outcomes in patients who adhered to treatment underscores the need for clinicians to address adherence issues with their patients. Sustaining adherence, particularly to the more time-consuming treatment of exercise, is a challenge.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. REFERENCES

Juvenile idiopathic arthritis (JIA) is one of the most common chronic medical conditions of childhood and it has potentially serious consequences of joint destruction and disability. More than half of patients with JIA have active disease that persists into adulthood (1, 2). In a summary of several studies, Oen concluded that JIA often extends past adolescence into adulthood (3). Guillaume et al (2) studied long-term outcomes in JIA. After 6 years of followup, 50% of patients studied extended to polyarthritis, 35% developed joint erosions, and 30% had uveitis. Most of the complications appeared early in the course of disease, implying that aggressive therapeutic approaches may be especially important early on. It has also been suggested that if remission does not occur within 10 years of disease onset, the disease will continue to be active (4).

Traditionally, outcomes in JIA have been determined by assessment of disease activity, with an emphasis on measures such as the active joint count and the erythrocyte sedimentation rate. In recent years, there has been tremendous growth in the development of measurement instruments that evaluate health status, functional status, disability, and quality of life in children with JIA (5). Factors associated with outcomes in JIA include disease-related factors such as severity at onset, early hip or wrist involvement, the presence of rheumatoid factor, and prolonged active disease (6). Other factors that may be important are psychosocial factors such as parental distress and disease intrusiveness (7).

Management of JIA involves a multidisciplinary treatment approach (8). Treatment may be complex, often including several types of medications, physical therapy, and splinting of joints. With new advances in pharmacologic treatments for JIA, it is important to assess whether adherence to these treatments predicts improved outcomes, especially since many of these treatments are very expensive. Evaluation of the effectiveness of any treatment's ability to achieve beneficial outcomes is dependent on adherence by the patient to that treatment (9). Moreover, it may be important to intervene early in the disease course of JIA in order to minimize substantial joint damage as is the case in adult rheumatoid arthritis (RA) (10, 11). Recent evidence points to earlier treatment being associated with higher remission rates in JIA (12). Sustained adherence may be affected by short-term outcomes; if patients perceive improvement while on their treatment regimen or if they believe that the treatment is helpful, they may be more apt to adhere to it (13).

The objective of this study was to determine whether adherence to treatment in children with JIA was associated with better clinical, functional, and quality of life outcomes. We assessed both adherence to pharmacologic and nonpharmacologic treatment and evaluated outcomes according to both clinical and parent/caregiver-rated scores.

PATIENTS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. REFERENCES

Study design and population.

A longitudinal study with data collection at 3 intervals over a 1-year period was conducted. Parents of patients with JIA who attended the JIA clinic at 2 pediatric hospitals (Montreal Children's Hospital at McGill University Health Centre, or British Columbia's Children's Hospital) were eligible for inclusion in the study. Parents were approached to participate if they had a sufficient comprehension of either English or French and if their child was currently undergoing treatment for JIA.

Data collection.

Parents of children with JIA completed several questionnaires repeatedly during the year. The study questionnaire package included the following: 1) the Parent Adherence Report Questionnaire (PARQ), addressing questions about adherence to treatment (14), 2) a study questionnaire addressing sociodemographics and questions related to problems encountered with the health care system (completed at 3-month intervals), 3) the Child Health Assessment Questionnaire (C-HAQ), addressing function/disability (completed at baseline, 6 months, and 12 months) (15), 4) the Juvenile Arthritis Quality of Life Questionnaire (JAQQ), addressing physical, mental, and social well-being (completed at baseline, 6 and 12 months) (16), and 5) the Symptom Checklist-90-Revised (SCL-90R) (17), which evaluated caregiver's psychological status (completed at baseline, 6 months, and 12 months). Clinical information including onset type of JIA, active joint count, date of diagnosis, and prescribed treatments were obtained from the patient's chart at each clinic visit. The study was approved by the Institutional Review Boards of the Montreal Children's Hospital and the British Columbia Children's Hospital.

Measures.

Treatment adherence was assessed by the caregiver's response to the question on the PARQ of how often they followed treatment recommendations as prescribed by the health care provider in the previous 3 months. The response was measured on a 100-mm visual analog scale (VAS), and was asked separately for pharmacologic and nonpharmacologic treatment (prescribed exercise). The PARQ has been shown to have satisfactory construct validity and test–retest reliability (intraclass correlation coefficients [ICCs] were 0.60 for medications and 0.88 for exercises) (14). Finally, caregivers were asked about any problems that they encountered with respect to the medical management of their child. Problems were defined as organizational (e.g., long waits, difficulty in getting appointments, seeing different doctors each time, etc.), communication-related (e.g., lack of understanding of clinicians' explanations and instructions, etc.), and treatment-related (e.g., side effects, difficulty with the treatment, etc.).

Clinical outcome at each 3-month interval was based on the active joint count. This was defined as the number of swollen joints plus the number of tender or warm joints with pain on movement that were not swollen (18).

Function/disability was measured by the C-HAQ, which comprises disability and discomfort components. The C-HAQ disability index (DI) is scored between 0 and 3, with 0–1 indicating mild to moderate disability, 1–2 describing moderate to severe disability, and 2–3 signifying severe to very severe disability (19, 20). The C-HAQ has excellent reliability and validity, and good discriminative properties. Further, mean scores for parents and children are highly correlated, suggesting that parents can reliably report for their children (21).

Quality of life was assessed with the JAQQ, which is a valid, reliable, and responsive instrument (16) that measures physical and psychosocial function, incorporates patient-specific data to measure quality of life, and is applicable to all age groups and chronic arthritis subtypes. In addition to 4 subscale scores and a total score, the JAQQ includes an assessment of pain and a global assessment/perception of health status relative to the previous assessment. The JAQQ has been shown to be more sensitive to change than other measures used in evaluating quality of life in children with JIA (16). Parental and child agreement for the JAQQ is high (22).

Clinical information (diagnosis, disease duration, active joint counts, and the child's age and sex) was abstracted from charts, and demographic information (e.g., socioeconomic status) was procured from the study questionnaire. Parental psychological distress was measured by the SCL-90R, a widely used and validated 90-item self-report measure of symptoms (9 symptom clusters) experienced during the past week (23). The clusters are summed to create a Global Severity Index. Clinically important distress corresponds to T scores ≥63. The test–retest reliability ICC score range is 0.47–0.69, and the internal consistency Cronbach's alpha range is 0.72–0.91 (24).

Statistical analysis.

Descriptive statistics were employed to characterize the cohort in terms of outcomes (function/disability, quality of life, pain, active joint count, and improvement), adherence to medication and exercise, JIA onset type, age, sex, maternal education level, disease duration, parental distress, and perceived problems regarding management of the disease.

Because the outcomes were skewed, they were categorized. The health assessment score (C-HAQ DI) was classified as mild (score of 0–1) or moderate to severe (score >1). No one in our cohort had a C-HAQ DI score >2. We performed a secondary analysis using the cutoff of 0.6 for the C-HAQ (mild-moderate disability or higher) as recommended by Dempster et al (25). Active joint count was classified as >1 active joints versus ≤1 active joints, as it has been shown that a score >1 joint was considered predictive of poorer prognosis (2). The JAQQ total score was dichotomized as ≤2 (little or no difficulty performing activities) versus >2 (moderate to high difficulty). We also explored alternative cutoff points for the JAQQ, at either 1.50 or 1.75. Parent's global assessment of overall well-being was dichotomized as condition being better versus being the same or worse. Finally, the pain VAS subscale on the C-HAQ and the JAQQ were dichotomized at the median or at the midpoint (50 mm). The rationale for the latter was to differentiate between those who may have had a somewhat more substantial amount of pain. Adherence to medication and exercise variables were grouped into tertiles to ease interpretability.

Generalized estimating equations (GEEs) were used to explore the influence of adherence to treatment on outcomes. These models allow for repeated measures analysis with both discrete and continuous covariates. The GEE model accounts for intrasubject correlations among repeated measurements on the same subject, and it improves power compared with treating both of the 6-month intervals alone. Separate models were constructed for each of the outcome measures and for parent-reported adherence to medication and exercise. In addition, a dichotomous measure of outcome (improved or not improved) was composed of 3 out of 5 of the following measures: an improvement in the parental global assessment and/or at least 30% improvement in any of the continuous measures (C-HAQ disability index score, active joint count, JAQQ total score, and pain due to illness). Finally, we conducted a logistic regression model with adherence at baseline and its association with subsequent outcome at 1 year.

Covariates included in these analyses were age, sex, disease duration, perceived problems regarding management of the disease, and parental distress. All analyses were performed using SAS software (SAS Institute, Cary, NC).

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. REFERENCES

A total of 235 patients consented to participate: 144 of 157 who were approached from Montreal, and 91 of 97 who were approached from Vancouver. However, only 182 (77%) returned the questionnaires: 120 from Montreal and 62 from Vancouver (nonrespondents did not return the questionnaires even after 3 reminders). Seven patients were further excluded from the Montreal sample because they did not have active disease over the year of study and did not undergo any active treatment (neither medication nor exercise). Therefore the final sample size was 175 patients. There were no differences between participants and nonparticipants for age at disease onset or age at recruitment, but mean active joint count was higher in participants (1.8 versus 0.6; P = 0.001). The general sample characteristics are described in Table 1. Sixty-nine percent of the sample were girls and the mean ± SD age was 10.2 ± 4.4 years (range 2–18 years). JIA onset type was distributed as follows: oligoarthritis 44.6%, polyarthritis (rheumatoid factor negative and positive combined) 20.6%, systemic arthritis 9.1%, enthesitis-related arthritis 10.3%, psoriatic arthritis 9.7%, and other or undifferentiated arthritis 5.7%. Adherence levels and health status/outcome variables for the study group are described in Table 2. Mean caregiver-reported adherence varied between 86.1% and 90.4% for medications but was considerably lower for exercise, which varied between 54.2% and 61.1%. In terms of function (as per the C-HAQ DI), only 12.4% of the group was classified as moderately to severely disabled at baseline, although ∼50% had some reduced quality of life (median JAQQ score 2.1). Pain due to illness was extremely low, with a mean ± SD of 15.7 ± 21.3 mm on the VAS scale at the baseline measure. At baseline, 58.7% of parents stated that their child was better compared with the previous visit; however, this decreased to 43.4% and 41.5% at 6 and 12 months, respectively.

Table 1. Description of cohort at baseline, 6 months, and 12 months*
 Baseline (n = 175)6 months (n = 127)12 months (n = 105)
  • *

    Values are the number (percentage) unless indicated otherwise.

  • Global Severity Index score >63.

Age, mean ± SD years10.2 ± 4.410.1 ± 4.610.6 ± 4.3
Disease duration, mean ± SD years4.1 ± 3.64.4 ± 3.44.7 ± 3.2
Female120 (68.6)91 (71.7)73 (69.5)
Mother's education   
 Less than high school10 (6.8)10 (9.4)4 (4.7)
 Completed high school48 (32.7)36 (34.0)26 (30.6)
 Post-secondary junior college45 (30.6)28 (26.4)22 (25.9)
 University44 (29.9)32 (30.2)33 (38.8)
Perceived problem related to  organization, communication,  or treatment69 (41.1)45 (38.5)27 (27.6)
Severe parental distress24 (13.7)9 (7.1)6 (5.7)
Table 2. Mean ± SDs for adherence and outcomes measured at baseline, 6 months, and 12 months*
 Baseline (n = 175)6 months (n = 127)12 months (n = 105)
  • *

    JAQQ = Juvenile Arthritis Quality of Life Questionnaire.

Adherence to medication by caregiver86.1 ± 26.090.4 ± 19.188.6 ± 20.0
Adherence to exercise by caregiver54.5 ± 31.661.2 ± 29.254.2 ± 29.4
Health assessment score disability index0.3 ± 0.40.2 ± 0.30.2 ± 0.4
Quality of life total score (JAQQ)2.2 ± 1.21.8 ± 1.11.9 ± 1.0
Active joint count1.8 ± 3.81.3 ± 3.31.1 ± 2.9
Pain due to illness15.7 ± 21.314.1 ± 22.015.0 ± 21.3
Degree of overall pain17.5 ± 23.313.8 ± 22.614.2 ± 19.4

Results of the GEE repeated measures analysis indicate that moderate adherence to medications is associated with subsequent lower active joint count. Moderate and high adherence to exercise is associated with subsequent improved global assessment. Moderate adherence to exercise is associated with lower perception of pain due to illness. These results are shown in Tables 3 and 4. Using the 0.6 cutoff point for the C-HAQ instead of 1, we found that moderate adherence to exercise was associated with better functional score (odds ratio [OR] 0.13, 95% confidence interval [95% CI] 0.03–0.54). Using the 1.5 cutoff point for the JAQQ, adherence to exercise was associated with better health-related quality of life scores (moderate adherence to exercise: OR 0.40, 95% CI 0.17–0.96; high adherence to exercise: OR 0.40, 95% CI 0.16–0.98).

Table 3. Association between adherence to medications and outcomes by generalized estimating equation regression analysis*
OutcomeAdherence to exerciseAdjusted OR (95% CI)P
  • *

    OR = odds ratio; 95% CI = 95% confidence interval; C-HAQ = Childhood Health Assessment Questionnaire; JAQQ = Juvenile Arthritis Quality of Life Questionnaire.

  • Adjusted for age, sex, duration of disease, parental distress status, and perceived problems related to organization, communication, or treatment.

Functional score (C-HAQ ≥1 vs. 0–1)LowReference 
 Moderate0.83 (0.20–3.38)0.789
 High1.04 (0.34–3.20)0.945
Quality of life (JAQQ >2 vs. ≤2)LowReference 
 Moderate0.79 (0.39–1.59)0.513
 High1.34 (0.69–2.62)0.391
Active joint count (>1 vs. 0–1)LowReference 
 Moderate0.47 (0.22–0.99)0.049
 High0.83 (0.40–1.69)0.602
Global assessment relative to lastLowReference 
 assessmentModerate0.73 (0.37–1.46)0.376
 High0.65 (0.34–1.22)0.184
Pain due to illness in past weekLowReference 
 (median >6 vs. ≤6)Moderate0.95 (0.48–1.91)0.896
 High0.63 (0.31–1.30)0.212
Pain due to illness in past weekLowReference 
 (score ≥50 vs. <50)Moderate2.32 (0.77–7.04)0.132
 High2.17 (0.65–7.21)0.215
Degree of overall pain in last weekLowReference 
 (median ≥8 vs. <8)Moderate0.69 (0.35–1.37)0.299
 High0.64 (0.32–1.28)0.212
Degree of overall pain in last weekLowReference 
 (score ≥50 vs. <50)Moderate0.92 (0.35–2.42)0.865
 High2.26 (0.76–6.68)0.132
Improvement (global impression and/LowReference 
 or ≥30% in 3 out of 5)Moderate0.28 (0.05–1.50)0.135
 High0.52 (0.15–1.82)0.317
Table 4. Associations between adherence to prescribed exercise and outcomes by generalized estimating equation regression analysis*
OutcomeAdherence to exerciseAdjusted OR (95% CI)P
  • *

    See Table 3 for definitions.

  • Adjusted for age, sex, duration of disease, parental distress status, and perceived problems related to organization, communication, or treatment.

Functional score (C-HAQ ≥1 vs. 0–1)LowReference 
 Moderate0.13 (0.03–0.54)0.006
 High0.56 (0.16–1.99)0.356
Quality of life (JAQQ >2 vs. ≤2)LowReference 
 Moderate0.55 (0.28–1.11)0.101
 High0.68 (0.32–1.45)0.323
High active joint count (>1 vs. 0–1)LowReference 
 Moderate0.67 (0.32–1.40)0.286
 High0.75 (0.37–1.52)0.421
Global assessment relative to lastLowReference 
 assessmentModerate2.34 (1.13–4.84)0.024
 High2.15 (1.02–4.53)0.049
Pain due to illness in past weekLowReference 
 (median >6 vs. ≤6)Moderate0.66 (0.30–1.43)0.296
 High0.67 (0.31–1.46)0.322
Pain due to illness in past weekLowReference 
 (score ≥50 vs. <50)Moderate0.14 (0.04–0.50)0.002
 High0.48 (0.16–1.41)0.165
Degree of overall pain in last weekLowReference 
 (median ≥8 vs. <8)Moderate0.82 (0.40–1.68)0.594
 High0.67 (0.35–1.29)0.238
Degree of overall pain in last weekLowReference 
 (score ≥50 vs. <50)Moderate0.44 (0.15–1.27)0.118
 High0.97 (0.42–2.28)0.950
Improvement (global impression and/LowReference 
 or ≥30% in 3 out of 5)Moderate0.93 (0.17–5.06)0.934
 High1.17 (0.25–5.39)0.839

The logistic regression analysis showed no statistically significant associations between adherence to medication and outcomes, although the estimated odds ratios were consistent with those in the GEE analysis (data not shown). With respect to adherence to exercise, the results were similar to those of the GEE analysis. Moderate adherence to exercise was associated with decreased pain due to illness and better quality of life, and both moderate and high adherence to exercise were associated with less overall pain (Table 5).

Table 5. Association between adherence to prescribed exercise at baseline and outcomes at 12 months by logistic regression analysis*
OutcomeAdherence to exerciseAdjusted OR (95% CI)P
  • *

    See Table 3 for definitions.

  • Adjusted for age, sex, duration of disease, parental distress status, and perceived problems related to organization, communication, or treatment.

Functional score (C-HAQ ≥1 vs. 0–1)LowReference 
 Moderate0.12 (0.01–2.18)0.250
 High0.30 (0.03–3.53)0.889
Quality of life (JAQQ >2 vs. ≤2)LowReference 
 Moderate0.19 (0.04–0.88)0.040
 High0.56 (0.14–2.25)0.677
High active joint count (>1 vs. 0–1)LowReference 
 Moderate0.27 (0.05–1.49)0.198
 High0.51 (0.11–2.39)0.963
Global assessment relative to lastLowReference 
 assessmentModerate2.94 (0.65–13.31)0.426
 High3.36 (0.68–16.62)0.293
Pain due to illness in past weekLowReference 
 (median >6 vs. ≤6)Moderate0.08 (0.01–0.42)0.006
 High0.24 (0.05–1.21)0.807
Pain due to illness in past week (scoreLowReference 
 ≥50 vs. <50)Moderate0.70 (0.03–15.31)0.933
 High0.39 (0.02–10.32)0.591
Degree of overall pain in last weekLowReference 
 (median ≥8 vs. <8)Moderate0.15 (0.03–0.76)0.036
 High0.12 (0.02–0.63)0.034
Degree of overall pain in last weekLowReference 
 (score ≥50 vs. <50)Moderate0.61 (0.05–7.83)0.653
 High0.12 (0.01–3.73)0.244
Improvement (global impression and/orLowReference 
 ≥30% in 3 out of 5)Moderate0.37 (0.06–2.48)0.431
 High0.55 (0.09–3.17)0.888

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. REFERENCES

The results of this study indicate that adherence to treatment in JIA is associated with improved outcomes. Specifically, children who adhered to taking their prescribed medications had subsequent improved active joint count scores and those who adhered moderately to doing exercises had better global assessment scores, better function, and less pain due to arthritis.

Although studies have indicated the efficacy of various pharmaceutical treatments (27), there has been little evaluation of the effectiveness of these treatments (i.e., real life use of the medications and outcomes). Moreover, the shift in treatment paradigm, similar to that in the treatment of adult RA, with early combination treatment (as opposed to the gradual add-on approach beginning exclusively with nonsteroidal antiinflammatory drugs) (28) may increase the complexity of treatment. Delayed beneficial effects and the need for sustained adherence may also decrease adherence to treatment (29). In our study, most patients perceived that they were adherent to medications. Nevertheless, our results indicate that those who were adherent had better clinical outcomes. This, in addition to the studies on efficacy, may help inform families about the importance of adhering to the medication regimen. It also underscores the need for the physician to address issues relating to adherence in order to optimize outcomes for the patient.

There have been a few studies that have indicated the benefits of prescribed exercise in improving certain outcomes in children (30–32). However, many of these involved intensive, short-lived exercise programs. This is the first study to demonstrate that those who adhered to their prescribed exercise programs actually had better results with respect to global improvement, function, and decreased pain. The issue of adhering to prescribed exercise programs needs to be addressed by the health care provider as well and appears to be quite important in improving generalized functional outcomes.

Strategies to improve adherence in JIA have been studied and appear to be successful. Rapoff et al demonstrated that by using a reinforcement program, they were able to improve adherence in a child with JIA (33). An educational intervention also appeared beneficial to improving adherence in younger children with JIA (34). A more recent randomized controlled trial indicated that adherence to treatment in JIA was significantly improved by a combined behavioral and educational intervention (35). In an earlier analysis, we determined that factors associated with higher perceived adherence to medications included perceived helpfulness of medications and lower disease severity; those associated with higher perceived adherence to exercise were a younger age, child involvement in responsibility for treatment, and higher perceived helpfulness of the treatment (13). This reinforces the need for education regarding usefulness of treatment and may encourage health care professionals and parents to increase the children's involvement in their own treatment, especially for older children.

The different outcomes that are affected by medications and by exercise warrant further attention. Medications had an effect on clinical outcome (reduction in swollen, painful, and warm joints) whereas exercise affected parental perceptions of global improvement, function, and decrease in pain. Although our study did not explicitly focus on exercising when the joint is painful, the results indicate that moderate adherence to exercise was associated with a subsequent reduction in pain and global improvement. This may further encourage patients to adhere to their exercise regimens, at least moderately, even when their joints are painful. Physical therapists are trained to provide therapeutic exercise programs that conform to the patient's pain tolerance. Possibly, moderate adherence to exercise is adequate to achieve better outcomes. The benefits of generalized exercise and better physical fitness in improving outcomes in JIA are known (30, 36) and may also provide further impetus for patients to adhere to their therapy programs.

The positive associations among adherence and improved outcomes appeared mostly in moderate levels of adherence. Although not statistically significant, the estimated odds ratios indicated improved outcomes for high levels of adherence as well. The absence of a dose– response relationship between adherence to medication and outcomes may be due to the fact that adherence to medication was extremely high in our sample, so that even “moderate” adherence in our sample was in fact high adherence. With respect to exercise, perhaps a moderate level of exercising would be considered optimal.

There are a number of limitations to this study. Adherence was measured based on parents' reports, which may be biased. There may be differences between caregiver recall of a child's treatment regimen and actual recommendations (37). Parents may overestimate their adherence. Although parent-reported adherence to medication was quite high, this was not the case at all for adherence to exercise. This may possibly indicate that parents were actually quite truthful regarding perceived adherence. In addition, we previously verified agreements regarding adherence between children and parents and found fair agreement for medication (ICC of 0.30) and high agreement for exercise (ICC of 0.80) (38). Another potential limitation is that those who participated in the study may be those who were most likely to adhere. This would represent a selection bias. Losses to followup over the 1-year period may also add to this, as perhaps those who were less adherent would tend to drop out. This may be one reason for the relatively stable adherence levels over time. However, the association between adherence and outcomes should not be affected unless participation in the study was also affected by outcomes. If those with better outcomes tended to remain in the cohort, we may have an overestimate of the effect of adherence. Those who participated in the study at baseline actually had a higher active joint count (worse disease), which would offset this potential overestimate. Furthermore, we found no significant differences between those who dropped out of the study and those who remained (data not shown).

Although our results are encouraging, it is important to note that adherence to exercise was considerably lower than that for medications. The improved outcomes in those patients who adhered to treatment may provide more incentive to others to adhere to treatment. Sustaining adherence, particularly to the more time-consuming treatment of exercise, is a challenge. Clinicians should assess adherence and use strategies to optimize adherence in order to maximize treatment benefits for their patients with JIA.

AUTHOR CONTRIBUTIONS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. REFERENCES

Dr. Ehrmann Feldman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study design. Ehrmann Feldman, De Civita, Dobkin, Malleson, Duffy.

Acquisition of data. Ehrmann Feldman, Dobkin, Malleson, Duffy.

Analysis and interpretation of data. Ehrmann Feldman, Malleson, Meshefedjian.

Manuscript preparation. Ehrmann Feldman, De Civita, Malleson, Meshefedjian, Duffy.

Statistical analysis. Ehrmann Feldman, Meshefedjian.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. AUTHOR CONTRIBUTIONS
  8. REFERENCES