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Keywords:

  • End-stage renal disease;
  • kidney transplant;
  • transplant outcomes;
  • transplant waiting list

Abstract

  1. Top of page
  2. Abstract
  3. Adults
  4. Children and Adolescents

ABSTRACT  A shortage of kidneys for transplant remains a major problem for patients with end-stage renal disease. The number of candidates on the waiting list continues to increase each year, while organ donation numbers remain flat. Thus, transplant rates for adult wait-listed candidates continue to decrease. However, pretransplant mortality rates also show a decreasing trend. Many kidneys recovered for transplant are discarded, and discard rates are increasing. Living donation rates have been essentially unchanged for the past decade, despite introduction of desensitization, non-directed donations, and kidney paired donation programs. For both living and deceased donor recipients, early posttransplant results have shown ongoing improvement, driven by decreases in rates of graft failure and return to dialysis. Immunosuppressive drug use has changed little, except for the Food and Drug Administration approval of belatacept in 2011, the first approval of a maintenance immunosuppressive drug in more than a decade. Pediatric kidney transplant candidates receive priority under the Share 35 policy. The number of pediatric transplants peaked in 2005, and decreased to a low of 760 in 2011. Graft survival and short-term renal function continue to improve for pediatric recipients. Posttransplant lymphoproliferative disorder is an important concern, occurring in about one-third of pediatric recipients.

This transplant impacted my life and the lives of my friends, family and community. I am especially grateful to be able to raise my son, to take him out of foster care and give him a good home and loving family.

Towana, kidney/pancreas recipient

Perhaps the most striking highlight of the 2010 and 2011 data is how little has changed. Organ donation numbers are relatively flat and the waiting list continues to grow. The shortage of kidneys remains a major problem for patients with end-stage renal disease (ESRD). Thus, there are attempts to increase the donor pool, and the kidney donor profile index (KDPI), which reflects the overall quality of deceased donor kidneys, continues to increase, especially for expanded criteria donors (ECD) (Figures 2.11, 2.12).

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Figure KI 2.11 . Mean kidney donor profile index (KDPI)  Patients receiving a kidney-only, deceased-donor transplant. Donors with a missing value for height, weight, or creatinine are excluded. KDPI is based on donor factors only; the percentiles are derived by mapping to the 2011 population of kidneys recovered for transplant.

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Figure KI 2.12 . Kidney donor profile index (KDPI) scores for ECD & SCD kidneys, 2010  All deceased donors whose kidney was transplanted in the given year, by SCD/ECD status. Each transplanted kidney is counted separately. Donors with a missing value for height, weight, or creatinine are excluded. KDPI is based on donor factors only; the percentiles are derived by mapping to the 2011 population of kidneys recovered for transplant.

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Adults

  1. Top of page
  2. Abstract
  3. Adults
  4. Children and Adolescents

Waiting List

The number of kidney transplant candidates on the waiting list continues to increase each year (Figure 1.1). In 2003, a major change in Organ Procurement and Transplantation Network (OPTN) kidney allocation policy allowed candidates listed as inactive to accumulate points for waiting time. As a consequence of this change, and of the increasing time between wait-listing and transplant, many transplant centers now list candidates before evaluation is complete. The number of candidates who are inactive at any time within 7 days of wait-listing increased from 718 in 2003 to 9,628 in 2011. The most common reasons for inactive status among these candidates were incomplete candidate work-up (69.0%), insurance issues (9.5%), and candidate too sick (7.7%) (Figure 1.3). Importantly, however, the number of active candidates on the waiting list at the end of each year continued to increase, from 7,404 in 2003 to 32,501 in 2011 (Figure 1.1).

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Figure KI 1.1 . Adult patients waiting for a kidney transplant  Patients waiting for a transplant. A “new patient” is one who first joins the list during the given year, without having listed in a previous year. However, if a patient has previously been on the list, has been removed for a transplant, and has relisted since that transplant, the patient is considered a “new patient.” Patients concurrently listed at multiple centers are counted only once. Those with concurrent listings and active at any program are considered active; those inactive at all programs at which they are listed are considered inactive.

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Figure KI 1.3 . Reasons for inactive status among kidney transplant listings, 2011  Reasons for inactive status of listings in 2011. Since patients can be concurrently listed at more than one center and have different reasons for going inactive at each center, each listing is counted separately.

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The wait-listed population continues to age. Since 1998, candidates aged 50 years or older represent an increasing proportion of wait-listed candidates (Figure 1.4). From a patient perspective, the steady annual trend of increased wait-listing of prevalent dialysis patients of all ages is encouraging (Figure 1.6).

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Figure KI 1.4 . Distribution of adult patients waiting for a kidney transplant  Patients waiting for a transplant any time in the given year. Age determined on the earliest of listing date or December 31 of the given year. Concurrently listed patients are counted once.

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Figure KI 1.6 . Prevalent dialysis patients wait-listed for a kidney transplant, by age  Prevalent dialysis patients, all ages, wait-listed for a kidney-alone transplant. Percentage calculated as the sum of wait-list patients divided by the sum of point prevalent dialysis patients on December 31 of each year (data from the United States Renal Data System).

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Increases in the number of candidates on the waiting list and relatively flat organ donation rates have resulted in steady decreases in transplant rates for adult wait-listed candidates since 1998 (Figure 1.7). In 1998, the deceased donor transplant rate was 20.6 transplants per 100 wait-list years, compared with 11.4 transplants per 100 wait-list years in 2011. As a consequence, in the past 3 years, more than 20,000 wait-listed candidates have been removed from the waiting list because they died or became too sick to undergo transplant (Figure 1.8). A positive note is a steady trend toward decreasing pre-transplant mortality rates in wait-listed candidates (Figure 1.14). The percentage of wait-listed candidates who received a deceased donor kidney within 5 years of listing varies greatly by donation service area (DSA) (Figure 1.11); this observation is worthy of more detailed study. Notably, 30.5% of candidates with panel-reactive antibody (PRA) of 80% to 100% undergo transplant within 5 years, not greatly dissimilar to the 36.0% who undergo transplant with less than 1% PRA (Figure 1.12). This rate of transplant in candidates with PRA of 80% to 100% is due to the allocation priority points provided to these high-PRA candidates.

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Figure KI 1.7 . Kidney transplant rates among adult waiting list candidates, by age  Patients waiting for a transplant; age as of January 1 of the given year. Yearly period prevalent rates for all transplants/deceased donor transplants are computed as the number of all transplants/deceased donor transplants per 100 patient years of waiting time in the given year. All waiting time per patient per listing is counted, and all listings that end in a transplant for the patient are considered transplant events.

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Figure KI 1.8 . Kidney transplant waiting list activity among adult patients  Patients with concurrent listings at more than one center are counted once, from the time of earliest listing to the time of latest removal. Patients listed, transplanted, and re-listed are counted more than once. Patients are not considered “on the list” on the day they are removed. Thus, patient counts on January 1 may be different from patient counts on December 31 of the prior year.

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Figure KI 1.14 . Pre-transplant mortality rates among adult patients wait-listed for a kidney transplant  Patients waiting for a transplant. Mortality rates are computed as the number of deaths per 100 patient-years of waiting time in the given year. For rates shown by different characteristics, waiting time is calculated as the total waiting time in the year for patients in that group. Only deaths that occur prior to removal from the waiting list are counted. Age is calculated on the latest of listing date or January 1 of the given year. Other patient characteristics come from the OPTN Transplant Candidate Registration form.

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Figure KI 1.11 . Percent of adult wait-listed patients, 2006, who received a deceased donor kidney transplant within five years, by DSA  Patients with concurrent listings in a single DSA are counted once in that DSA, and those listed in multiple DSAs are counted separately per DSA.

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Figure KI 1.12 . Adult wait-listed patients who received a deceased donor kidney transplant within five years  Patients with concurrent listings at more than one center are counted once, from the time of earliest listing to the time of latest removal. Patients listed, transplanted, and re-listed are counted more than once.

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Donation

After several years with little change, the deceased donor kidney donation rate (per 1,000 deaths) has increased slightly (Figure 2.1). However, many kidneys recovered for transplant are discarded. The discard rate increased steadily from 12.7% in 2002 to 17.9% in 2011 (Figure 2.5). Figure 2.6 lists reasons for deceased donor organ discard after nephrectomy. Importantly, donor kidneys are discarded only after being offered locally, regionally, and nationally. Given the tremendous organ shortage, the continuing high rate of discard is of concern. Currently, each organ procurement organization (OPO) is responsible for notifying OPTN of the reason for discard. Yet different centers may turn down the same kidney offer for different reasons (e.g., patient too sick versus donor quality). A kidney that might not be accepted for one patient (e.g., new on the list, 0% PRA) might be accepted for another (100% PRA). Determining how many centers rejected a kidney before it was discarded will be important, as will determining whether kidneys discarded in one region have characteristics similar to kidneys used in another region.

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Figure KI 2.1 . Deceased donor kidney donation rates  Numerator: Deceased donors age less than 65 whose kidney(s) were recovered for transplant. Denominator: US deaths per year, age less than 65. (Death data available at http://www.cdc.gov/nchs/products/nvsr.htm.)  Donors who donated two kidneys are counted twice.

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Figure KI 2.5 . Discard rates for kidneys recovered for transplant  Percent of kidneys discarded out of all kidneys recovered for transplant. Kidneys are counted individually.

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Figure KI 2.6 . Reasons for kidney discards among kidneys removed for transplant but not transplanted, 2011  Reasons for discard among kidneys recovered for transplant but not transplanted in 2011.

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In 2011, kidneys were not recovered from 734 (9.0%) donors from whom at least one organ was recovered for transplant (Figure 2.8). The major reasons for non-recovery of deceased donor kidneys at the time another organ was recovered were poor organ function (44.3%), donor medical history (11.1%), other (9.3%), and organ refused by all national programs (6.6%) (Figure 2.9). The major reasons for discard after recovery were biopsy findings (37.3%), no recipient identified (16.6%), poor organ function (9.2%), anatomic abnormalities (7.1%), and other (17.5%) (Figure 2.6). The relatively high discard rate may be related to the steady increase in the KDPI. However, given the organ shortage, it would be beneficial to better understand how 16.6% of discarded kidneys were discarded because no recipient could be identified.

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Figure KI 2.8 . Donors whose kidneys were not recovered  Donors whose kidney(s) were not recovered but at least one other organ was.

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Figure KI 2.9 . Reasons for kidneys not being recovered at the time of another organ's recovery  Reasons for non-recovery of kidney, in donors who had at least one other non-renal organ recovered for transplant, 2011. If the same reason was recorded for each kidney, it was only counted once.

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Although donation rates have not greatly changed, the percentage of transplants performed from donation after circulatory death (DCD) has steadily increased, from 1.4% in 1998 to 15.8% in 2011 (Figure 4.6). Percentages of DCDs vary widely by DSA, ranging from less than 5% to more than 30% (Figure 4.7). At the same time, there is considerable variation by DSA in kidney transplant rates per 100 patient-years on the waiting list (Figure 1.11). Of note, some centers with low DCD use have high deceased donor transplant rates (Figure 4.8). It would be interesting to determine if this is due to low listing rates, different donor management protocols, or other reasons.

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Figure KI 4.6 . Use of DCD kidneys among adult kidney-alone transplant recipients, by recipient age  Percent of deceased donor transplants using a DCD donor.

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Figure KI 4.7 . Percent of adult deceased donor kidney transplants that are DCD, by DSA, 2011  Percent of deceased donor transplants using a DCD donor, by DSA of the transplanting center.

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Figure KI 4.8 . Kidney transplant rates per 100 patient years on the waiting list among adult candidates, by DSA, 2010–2011  Transplant rates by DSA of the listing center, limited to those on the waiting list in 2010 and 2011; includes deceased and living donor rates. Maximum time per person on the list is two years.

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Nationally, living donation rates have been essentially unchanged for the past decade (Figures 3.1, 3.3), despite introduction of desensitization, non-directed donations, and kidney paired donation programs. Although national rates are unchanged, since 2005 donation rates per million population have increased in some areas of the country and decreased by 5% to 10% in other areas (Figure 3.4). Comparison of living donation rates by state (Figure 3.4) with deceased donation rates by state (Figure 2.2) reveals interesting differences. Some states have high rates for both; others, low rates for both; still others, high rates for one and low rates for the other. Reasons for this variability should be studied.

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Figure KI 3.1 . Kidney donations from living donors  Number of living donor donations; characteristics recorded on OPTN Living Donor Registration form.

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Figure KI 3.3 . Living donor kidney donation rates  Number of living donors whose relevant organ was recovered for transplant each year. Denominator: US population age 70 and younger (population data downloaded from http://www.census.gov/popest/national/asrh/2009-nat-res.html).

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Figure KI 3.4 . Living donor kidney donation rates (per million population), by state  Number of living donors residing in the 50 states whose kidney was recovered for transplant in the given year. Denominator: US population age 70 and younger (population data downloaded from http://www.cdc.gov/nchs/nvss/bridged_race/data_documentation.htm).

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Figure KI 2.2 . Deceased donor kidney donation rates (per 1,000 deaths), by state  Numerator: Deceased donors residing in the 50 states whose kidney(s) were recovered for transplant in the given year range. Denominator: US deaths by state during the given year range (death data available at http://www.cdc.gov/nchs/products/nvsr.htm). Rates are calculated within ranges of years for more stable estimates. Donors who donated two kidneys are counted twice.

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The number of paired donation transplants increased steadily, from 2 in 2000 to 429 in 2011 (Figure 3.5). Hopefully, with the development of donor chain transplants, and with a national system for paired donation, the numbers will continue to grow.

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Figure KI 3.5 . Paired kidney donations  Counts include “domino” donation chains.

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Poor follow-up of living donors remains an important issue. At 12 months after donation, readmission data are unreported for 20.0% of donors (Figure 3.9), and estimated glomerular filtration rate (eGFR) is unknown for 49.7% of donors (Figure 3.7).

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Figure KI 3.9 . Readmission to the hospital in the first year among live kidney donors, 2010  Cumulative readmission to the hospital. “Unknown” means that patient has been lost to follow-up as of this follow-up visit. The six-week time point is recorded at the earliest of discharge or six weeks post-donation.

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Figure KI 3.7 . Mean pre- & post-operative eGFR & systolic blood pressure among kidney donors, 2009  eGFR estimated by CKD-EPI formula. (Levey AS et al., Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). A new equation to estimate glomerular filtration rate. Ann Intern Med., 2009 May 5; 150(9):604–12).

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Transplants

Commensurate with the increasing age of candidates on the waiting list, the number of transplants performed annually in patients aged 50 years or older has steadily increased, and the number performed annually in patients aged 65 years or older tripled between 1998 and 2011 (Figure 4.2). Also of note, since 2006 the number of transplants performed in black, Hispanic, and Asian patients has increased, and the number performed in white patients has decreased (Figure 4.2). However, transplant rates (per 100 patient-years on the waiting list) have been steadily decreasing since 1998 (Figure 4.3).

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Figure KI 4.2 . Adult kidney transplants  Patients receiving a kidney-alone or simultaneous kidney-pancreas transplant. Retransplants are counted.

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Figure KI 4.3 . Kidney transplant rates in adult waiting list candidates  Patients waiting for a transplant. Transplant rates are computed as the number of transplants per 100 patient-years of waiting time in the given year. All waiting time per patient per listing is counted, and all listings that end in a transplant for the patient are considered transplant events.

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Outcomes

The steady improvement in early post-transplant results is an exciting observation. Over the past 15 years, for both living and deceased donor transplant recipients, 90-day, 6-month, and 1-, 3-, and 5-year results have shown ongoing improvement (Figures 6.1, 6.3, 6.4). There is now a suggestion of improvement in 10-year results (Figures 6.3, 6.4), and, in the past decade, for both living and deceased donor transplants, half-life has improved by about 1 year (for grafts functioning beyond the first year) (Figure 6.7). This improvement has been driven by a decrease in the rate of graft failure and return to dialysis. Rates of death with graft function have not declined. As of June 30, 2011, 164,200 adults in the US were surviving with a functioning kidney graft, about twice as many as a decade earlier (Figure 6.8).

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Figure KI 6.1 . Death-censored graft failure within 90 days among adult kidney transplant recipients  Retransplantation, graft failure, or return to dialysis within the first 90 days after transplant date. Graft failure due to death is not included. Graft failure dates are determined from multiple data sources, including the OPTN Transplant Recipient Registration, OPTN Transplant Recipient Follow-up.

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Figure KI 6.3 . Outcomes among adult kidney transplant recipients: deceased donor  Data are reported as probability of each outcome. Probabilities are unadjusted, computed using Kaplan-Meier competing risk methods. Death with function defined as no graft failure prior to death; return to dialysis defined as graft failure preceding death.

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Figure KI 6.4 . Outcomes among adult kidney transplant recipients: living donor  Data are reported as probability of each outcome. Probabilities are unadjusted, computed using Kaplan-Meier competing risk methods. Death with function defined as no graft failure prior to death; return to dialysis defined as graft failure preceding death.

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Figure KI 6.7 . Half-lives for adult kidney transplant recipients  Estimated graft half-lives and conditional half-lives. Half-lives are interpreted as the estimated median survival of grafts from the time of transplant. Conditional half-lives are interpreted as the estimated median survival of grafts which survive the first year.

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Figure KI 6.8 . Recipients alive & with a functioning kidney transplant on June 30 of the year  Transplants before June 30 of the year that are still functioning. Patients are assumed alive with function unless a death or graft failure is recorded. A recipient can experience a graft failure and drop from the cohort, then be retransplanted and re-enter the cohort.

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Of concern is the rate of post-transplant lymphoproliferative disorder (PTLD) in recipients who were negative for the Epstein-Barr virus (EBV) at the time of transplant (Figure 6.11). EBV status has been recognized as a risk factor for PTLD in children. However, by 5 years post-transplant, close to 2% of EBV-negative adults have developed PTLD. Rates are similar for patients receiving EBV-negative or EBV-positive donor organs.

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Figure KI 6.11 . Incidence of PTLD among adult patients receiving a kidney transplant in 2005–2009, by recipient Epstein-Barr virus (EBV) status at transplant  The cumulative incidence, defined as the probability of post-transplant lymphoproliferative disorder (PTLD) being diagnosed between the time of transplant and the given time, is estimated using Kaplan-Meier methods. PTLD is identified as either a reported complication or cause of death on the Transplant Recipient Follow-up forms or on the Post-transplant Malignancy form as polymorphic PTLD, monomorphic PTLD, or Hodgkin's Disease. Only the earliest date of PTLD diagnosis is considered, and patients are followed for PTLD until graft failure, death, or loss to follow-up. Patients are censored at graft failure because malignancies are not reliably reported after graft failure.

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Immunosuppressive Medication Use

The types and combination of types of immunosuppressive drugs used over the past few years have differed little. However, a highlight of 2011 was the first US Food and Drug Administration approval in more than a decade of a new maintenance immunosuppressive drug, belatacept. Although the drug was approved in June 2011, OPTN data submission forms were not changed to allow reporting of its use until fall 2011 (until then, the box marked “other” had to be checked). The 2012 report will provide the first annual snapshot of the clinical use of belatacept.

Children and Adolescents

  1. Top of page
  2. Abstract
  3. Adults
  4. Children and Adolescents

Waiting List

On September 28, 2005, the kidney allocation system was modified to give priority to pediatric candidates ahead of adult candidates locally, regionally, and nationally for nonzero mismatch kidney offers from donors aged 35 years or younger (OPTN Policy 3.5.11.5.1). The intent of this modification, referred to as “Share 35,” was to prioritize allocation of younger donor kidneys to address established goals of rapidly providing transplants to pediatric candidates with minimal impact on adult transplant rates. The effect of this policy on pediatric kidney transplant outcomes is an area of ongoing evaluation.

In 2011, almost half of new pediatric candidates added to the kidney transplant waiting list were listed as inactive. This number has continued to increase since the policy change in 2003 permitting waiting time to accrue while candidates are listed as inactive. Similarly, among prevalent pediatric wait-listed candidates, those listed as inactive outnumber those listed as active (Figure 8.1). Since 2007, the age distribution of pediatric candidates waiting for kidney transplant has changed (Figure 8.2). Candidates aged 11 to 17 years remain the most common pediatric age group listed (71.3%); however, candidates aged 1 to 5 years now represent the second-largest pediatric age group, having surpassed the group aged 6 to 10 years. The racial/ethnic distribution of wait-listed pediatric candidates has also changed. While the proportions of white and Asian candidates have remained relatively constant, the proportion of Hispanic candidates has increased and the proportion of black candidates has decreased. The etiology of ESRD has remained relatively constant; structural abnormalities are the most common cause in the youngest patients, and focal segmental glomerulosclerosis and glomerulonephritis increase in frequency with increasing age (Figure 8.3).

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Figure KI 8.1 . Pediatric patients waiting for a kidney transplant  Patients waiting for a transplant. A “new patient” is one who first joins the list during the given year, without having listed in a previous year. However, if a patient has previously been on the list, has been removed for a transplant, and has relisted since that transplant, the patient is considered a “new patient”. Patients concurrently listed at multiple centers are counted only once. Those with concurrent listings and active at any program are considered active; those inactive at all programs at which they are listed are considered inactive.

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Figure KI 8.2 . Distribution of pediatric patients waiting for a kidney transplant  Patients waiting for a transplant any time in the given year. Age determined on the lastest of listing date or January 1 of the given year. Concurrently listed patients are counted once. Primary cause of renal failure categorized according groups used by NAPRTCS. FSGS = focal segmental glomerulosclerosis. GN = glomerulonephritis.

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Figure KI 8.3 . Primary cause of ESRD in pediatric patients waiting for kidney transplant, 2007–2011, by age  Patients with concurrent listings at more than one center are counted once, from the time of earliest listing to the time of latest removal. Patients listed, transplanted, and re-listed are counted more than once. Age is computed at earliest listing date. FSGS = focal segmental glomerulosclerosis. GN = glomerulonephritis.

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In 2011, 13.1% of candidates on the waiting list had undergone a previous kidney transplant (Figure 8.4). The number of children and adolescents on the waiting list who had undergone a previous transplant varied from 98 in 1998 to 141 in 2008 and 119 in 2011 (data not shown). Of all candidates on the waiting list in 2011, 4.3% of those aged 0 to 5 years, 14.7% of those aged 6 to 10 years, and 15.5% of those aged 11 to 17 years were waiting for re-transplant. Among patients undergoing transplant in 2008, within 1 year of listing, 45.7% underwent deceased donor transplant, 13.9% underwent living donor transplant, 38.0% were still waiting at the end of 2011 (Figure 8.6). In contrast to mortality among patients waiting for other organs, pre-transplant mortality among pediatric candidates waiting for kidney transplant is low, 1.5 per 100 wait-list years in 2011 (Figure 8.8).

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Figure KI 8.4 . Prior kidney transplant in pediatric patients waiting for a kidney transplant, by age  Prior transplant is obtained from the OPTN Transplant Candidate Registration form.

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Figure KI 8.6 . Outcomes for pediatric patients waiting for a kidney transplant among new listings in 2008  Patients waiting for a transplant and first listed in 2008. Patients with concurrent listings at more than one center are counted once, from the time of the earliest listing to the time of latest removal.

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Figure KI 8.8 . Pre-transplant mortality rates among pediatric patients wait-listed for a kidney transplant, by age  Patients waiting for a transplant. Mortality rates are computed as the number of deaths per 100 patient-years of waiting time in the given 2-year interval. Waiting time is calculated as the total waiting time per age group in the interval. Only deaths that occur prior to removal from the waiting list are counted. Age is calculated on the latest of listing date or January 1 of the given period.

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Transplants

The number of pediatric kidney transplants peaked in 2005 at 899 and decreased to a low of 760 in 2011 (Figure 8.9). Re-transplant accounted for 9.1% of transplants performed in 2011 (Figure 8.10). The rate of deceased donor kidney transplants decreased from a peak of 60.2 per 100 wait-list years in 2006 to 44.4 per 100 wait-list years in 2011. The rate of living donor transplants increased from a nadir of 13.0 per 100 wait-list years in 2007 to 16.1 per 100 wait-list years in 2011 (Figure 8.11).

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Figure KI 8.9 . Pediatric kidney transplants (includes kidney-pancreas), by donor type  Patients receiving a kidney-alone or simultaneous kidney-pancreas transplant, by kidney donor type.

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Figure KI 8.10 . Percent of pediatric kidney transplants that are retransplants  Includes patients tranplanted after age 17, but listed at age 17 or younger. Retransplanted patients include only those with a prior kidney transplant.

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Figure KI 8.11 . Kidney transplant rates in pediatric waiting list candidates  Patients waiting for transplant. Transplant rates are computed as the number of transplants per 100 patient-years of waiting time in the given year. Patients with concurrent listings at multiple centers are counted once.

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In the past decade, the proportion of pediatric patients undergoing preemptive kidney transplant has remained steady at about 25% (Figure 8.12). The number of HLA mismatches has increased, which may be partly attributable to implementation of the Share 35 deceased donor kidney allocation system.

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Figure KI 8.12 . Characteristics of pediatric kidney transplant recipients, 1999–2001 & 2009–2011  Patients receiving a transplant. Retransplants are counted. PCOD categories follow NAPRTCS recommendations.

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Donation to pediatric recipients from related living donors has declined dramatically, by about 50%. Donation from “other” living donors has increased, possibly reflecting increased participation in kidney paired donation (Figure 8.13). Use of DCD kidneys increased over time to 4.6% in 2011 (Figure 8.14). No ECD kidneys have been used in pediatric recipients since 2006. The mean KDPI in pediatric recipients in 2011 was 40% (Figure 8.15). The KDPI is a numerical measure that combines 10 donor characteristics to express the quality of a donor kidney relative to other donors. It is derived by first calculating the Kidney Donor Risk Index (KDRI) using donor characteristics only, and then mapping the values against a reference group to obtain percentiles. The reference group used here is all kidneys recovered for transplant in 2011. Higher values of KDPI indicate poorer donor quality. For example, a kidney donor with a KDPI of 90% has a higher KDRI (and therefore higher estimated risk of post-transplant graft failure) than 90% of the reference group. The KDPI is based on these donor characteristics: age, race/ethnicity, hypertension status, diabetes status, serum creatinine level, cause of death (cere-brovascular, cardiac, etc.), height, weight, DCD status, and hepatitis C status.

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Figure KI 8.13 . Pediatric kidney transplants from living donors  Relationship of live donor to recipient is as indicated on the Living Donor Registration form.

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Figure KI 8.14 . Use of ECD or DCD donors in pediatric kidney transplant recipients  Patients receiving a DCD or ECD kidney transplant.

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Figure KI 8.15 . Distribution of kidney donor profile index (KDPI) in pediatric recipients of deceased donor kidneys  Patients receiving a kidney-only, deceased-donor transplant. Those whose transplant organ was missing a value for height, weight, or creatinine are excluded. KDPI is based on donor factors only; the percentiles are derived by mapping to the 2011 population of kidneys recovered for transplant.

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The age of deceased donor organs allocated to pediatric transplant recipients has changed over time, guided by changes in both clinical practice and allocation policy such as Share 35. Figure 8.16 shows the increase in deceased donor organs from donors aged younger than 35 years.

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Figure KI 8.16 . Donor age among pediatric kidney transplant recipients, by kidney status, before & after Share 35  Patients receiving a deceased donor transplant. Share 35 began in September 2005. SCD: standard criteria donor kidneys; DCD: donations after cardiac death. Data for expanded criteria donor (ECD) kidneys are not shown; n=41 ECD kidneys in 1998–2005 and 1 ECD kidney in 2006–2011. Donors of ECD kidneys are age 50+.

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Outcomes

Graft survival (patient survival with a functioning graft) has continued to improve among pediatric recipients over the past decade. Graft failure for deceased donor transplants was 3.7% at 6 months and 5.3% at 1 year for transplants in 2009-2010, 15.3% at 3 years for transplants in 2007-2008, 29.1% at 5 years for transplants in 2005-2006, and 51.4% at 10 years for transplants in 2001-2002 (Figure 8.24). Corresponding graft failure for living donor transplants was 1.6% at 6 months and 2.7% at 1 year for transplants in 2009-2010, 8.4% at 3 years for transplants in 2007-2008, 18.1% at 5 years for transplants in 2005-2006, and 35.7% at 10 years for transplants in 2001-2002 (Figure 8.25). The rate of late graft failure is traditionally measured by the graft half-life conditional on 1-year survival, defined as the time to when half of grafts surviving at least 1 year are still functioning. For deceased donor transplants, the estimated 1-year conditional half-life was 11.9 years for transplants in 2011 (Figure 8.26). For living donor transplants, the estimated 1-year conditional half-life was 15.3 years for transplants in 2011.

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Figure KI 8.24 . Outcomes among pediatric kidney transplant recipients: deceased donor  Data are reported as probablity of each outcome. Probabilities are unadjusted, computed using Kaplan-Meier competing risk methods. Death with function defined as no graft failure prior to death; return to dialysis defined as graft failure preceding death.

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Figure KI 8.25 . Outcomes among pediatric kidney transplant recipients: living donor  Data are reported as probablity of each outcome. Probabilities are unadjusted, computed using Kaplan-Meier competing risk methods. Death with function defined as no graft failure prior to death; return to dialysis defined as graft failure preceding death.

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Figure KI 8.26 . Half-lives for pediatric kidney transplant recipients  Estimated graft half-lives and conditional half-lives. Half-lives are interpreted as the estimated median survival of grafts from the time of transplant. Conditional half-lives are interpreted as the estimated median survival of grafts which survive the first year.

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Short-term renal function, measured by eGFR, has improved substantially in pediatric recipients over the past decade. The proportion of patients with eGFR of 90 mL/min/1.73 m2 or greater at discharge increased from 17.1% in 2000 to 33.9% in 2011, at 6 months post-transplant from 10.3% in 2000 to 25.7% in 2011, and at 1 year post-transplant from 6.7% in 2000 to 24.5% in 2010 (Figure 8.28). Almost 70% of patients in the 2011 cohort had eGFR of 60 mL/min/1.73 m2 or greater at discharge, CKD stage 1-2.

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Figure KI 8.28 . Distribution of eGFR, at discharge & at 6 & 12 months post-transplant among pediatric kidney transplant recipients  GFR estimated using the bedside Schwartz equation, and computed for patients alive with graft function at the given time point.

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PTLD is an important concern in pediatric transplantation. The highest risk for EBV infection and PTLD occurs for EBV-negative recipients of EBV-positive donor kidneys. This occurred in 32.5% of deceased donor recipients and 33.5% of living donor recipients (Figure 8.19). The incidence of PTLD among EBV-negative recipients was 4.5% at 5 years post-transplant, compared with 0.6% among EBV-positive recipients (Figure 8.21). Although PTLD is the most common type of malignancy in pediatric kidney transplant recipients, other types of malignancies are reported and they increase over time post-transplant (Figure 8.22).

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Figure KI 8.19 . Kidney donor-recipient Epstein-Barr virus (EBV) serology matching for pediatric transplant recipients, 2007–2011  Pediatric transplant cohort from 2007–2011. Donor EBV serology is reported on the OPTN Donor Registration form; recipient EBV serology is reported on the OPTN Recipient Registration form. Any evidence for a positive serology is taken to indicate that the person is positive for EBV; if all fields are unknown, not done, or pending the person is considered to be “unknown” for that serology; otherwise, serology is assumed negative.

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Figure KI 8.21 . Incidence of PTLD among pediatric patients receiving a kidney transplant, 1999–2009  The cumulative incidence, defined as the probability of post-transplant lymphoproliferative disorder (PTLD) being diagnosed between the time of transplant and the given time, is estimated using Kaplan-Meier methods. PTLD is identified as either a reported complication or cause of death on the Transplant Recipient Follow-up forms or on the Post-transplant Malignancy form as polymorphic PTLD, monomorphic PTLD, or Hodgkin's Disease. Only the earliest date of PTLD diagnosis is considered, and patients are followed for PTLD until graft failure, death, or loss to follow-up. Patients are censored at graft failure because malignancies are not reliably reported after graft failure.

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Figure KI 8.22 . Incidence of any malignancy in pediatric patients receiving a kidney transplant in 1999–2009  The cumulative incidence, defined as the probability of any malignancy being diagnosed between the time of transplant and the given time, is estimated using Kaplan-Meier methods. Malignancies are identified on the Malignancy forms or on the Transplant Recipient Follow-up forms. Causes of graft failure or causes of death attributed to a malignancy are included. Only the earliest date of diagnosis is included in the analysis, and patients are followed only until graft failure, death, or loss to follow-up. Patients are censored at graft failure because malignancies are not reliably reported after graft failure.

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Immunosuppressive Medication Use

Trends in maintenance immunosuppressive medications used in children and adolescents are similar to trends for adults. In 2011, 94.0% of pediatric transplant recipients received tacrolimus as part of the initial maintenance immunosuppressive medication regimen, and 92.6% received mycophenolate mofetil (Figure 8.23). In 2010, corticosteroids were used in 62.1% of transplant recipients at the time of transplant and in 62.5% at 1 year post-transplant. Induction therapy has changed in pediatric kidney transplantation. Decreased availability of the interleukin-2 receptor antagonist daclizumab likely contributed to decreased utilization. There has been a corresponding increase in the proportion of patients receiving T-cell depleting agents or no induction therapy.

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Figure KI 8.23 . Immunosuppression use in pediatric kidney transplant recipients  One-year post-transplant data for mTOR inhibitors and steroids limited to patients alive with graft function one year post-transplant. One-year post-transplant data are not reported for 1998 transplant recipients, as follow-up data were very sparse.

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