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Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
 
Am J Transplant. Author manuscript; available in PMC 2017 July 26.
Published in final edited form as:
PMCID: PMC5527691
NIHMSID: NIHMS882686

OPTN/SRTR 2015 Annual Data Report: Kidney

Abstract

The first full year of data after implementation of the new kidney allocation system reveals an increase in deceased donor kidney transplants among black candidates and those with calculated panel-reactive antibodies 98%–100%, but a decrease among candidates aged 65 years or older. Data from 2015 also demonstrate ongoing positive trends in graft and patient survival for both deceased and living donor kidney transplants, but the challenges of a limited supply of kidneys in the setting of increasing demand remain evident. While the total number of patients on the waiting list decreased for the first time in a decade, this was due to a combination of a decrease in the number of candidates added to the list and an increase in the number of candidates removed from the list due to deteriorating medical condition, as well as an increase in total transplants. Deaths on the waiting list remained at, but this was likely because of an increasing trend toward removing inactive candidates too sick to undergo transplant.

1 Introduction

This 2015 Annual Data Report is the first since the new kidney allocation system (KAS) was implemented in December 2014, providing an early opportunity to look for resulting changes in trends. While many previous 5- and 10-year trends continued unchanged, signals of the effect of the new allocation system were seen even at this early stage. A more detailed review of the pre- and post-KAS effects is provided in a separate chapter. While some effects of the new KAS are evident now, the transplant community will have to wait several more years to assess other potential effects, such as the potential long-term benefits of matching the lowest kidney donor profile index (KDPI) kidneys to recipients with the greatest likelihood of long-term benefit.

The 2015 data also show ongoing positive trends in unadjusted graft and patient survival for both deceased and living donor kidney transplants over the past decade. Unfortunately, these data continue to highlight the most fundamental challenge in managing the kidney transplant waiting list: an insufficient supply of kidneys in the setting of increasing demand. While the total number of patients on the list decreased for the first time in a decade, this decrease is due to a combination of a decrease in the number of new listings and an increase in the number of candidates removed due to deteriorating medical condition or other reasons, in addition to an increase in the number of transplants. The number of active candidates on the list continued to grow, along with waiting times and time on dialysis, a frustrating trend given the known survival, cost, and quality of life detriment of longer time on dialysis. Instead of a corresponding increase in the number of living donor kidney transplants given the growing waiting list, they actually declined over the past decade. A small increase in the number of living donor transplants did occur in 2015, but whether this represents a new positive trend remains to be seen.

2 Adult Kidney Transplant

2.1 Waiting List

For the first time in more than 10 years, the total number of patients on the waiting list decreased in 2015 from 99,120 at the start of 2015 to 97,680 at the end (Table KI 3); however, this was likely driven by a combination of a decrease in the number of new listings, a decrease in the number of inactive candidates, and an increase in the number of candidates removed due to deteriorating medical condition, in addition to an increase in the number of transplants. This decline was anticipated, since under the new KAS patients are given waiting time credit for time on dialysis, negating any benefit to maintaining inactive end-stage kidney disease patients on the list while the issue rendering them ineligible for transplant is addressed (Figure KI 1, Figure KI 2, Table KI 3). However, the increase in the number of active patients on the list continued, from less than 47,000 in 2005 to 61,234 in 2015. Despite the policy change giving waiting time credit for time on dialysis, the most common reason for inactive status at the time of listing remained incomplete candidate workup; only 6% were inactive at listing due to poor health status, essentially unchanged from previous years (Table KI 1). Of the 31,672 patients removed from the list in 2015, 17,611 underwent transplant, and nearly 5000 died. While the number of patients who died on the list was fairly stable over the past 3 years, despite increasing numbers on the list, an additional 4154 patients were removed from the list due to deteriorating medical condition (13.1% of removals), a nearly 3-fold increase over 5 years, from 1533 in 2010 (6% of removals) (Table KI 4; 2010 data obtained from the 2012 Annual Data Report). This increase may reflect an effort to remove patients deemed unlikely to ever be well enough for transplant before death is imminent; these patients can be relisted if clinical improvement is noted, with waiting time credit for time on dialysis. This possibility is supported by a decrease in 6-month mortality in patients removed from the list (Figure KI 23); however, this trend should be monitored to ensure that overly aggressive removals from the list do not adversely affect patients who may yet benefit from transplant.

Figure KI 1
New adult candidates added to the kidney transplant waiting list
Figure KI 2
Adults listed for kidney transplant on December 31 each year
Figure KI 23
Deaths within six months after removal among adult kidney walitlist candidates
Table KI 1
Reasons for inactive status among new adult kidney transplant listings, 2015
Table KI 3
Kidney transplant waitlist activity among adults
Table KI 4
Removal reason among adult kidney transplant candidates

The-10 year trend toward an increasing proportion of waitlisted patients aged 65 to 74 years continued; the proportion aged 65 years or older rose from 14.5% in 2005 to 22.0% in 2015 (Table KI 2). If the rate of change over the past 5 years continues, patients aged 65 years or older will outnumber those aged 35 to 49 years in 2020 (Figure KI 3). The racial distribution of the list remained relatively stable, with an ongoing slow increase in the proportion of Hispanic candidates (Figure KI 4). The proportion of candidates with kidney disease due to diabetes has steadily increased (Figure KI 5). Waiting time and time on dialysis for candidates at the time of the snapshot continued to increase. The proportion of candidates waiting more than 5 years rose from 11.4% in 2005 to 15.7% in 2015, while the proportion waiting less than 1 year continued to fall (Table KI 2, Figure KI 6). Nearly half of patients listed had been on dialysis for at least 4 years, 12.8% for at least 11 years (Figure KI 8). Interestingly, the only marked reversal of previous trends was in willingness to accept an expanded criteria donor (ECD) or KDPI-above-85% kidney. In 2004, 42.8% reported willingness to accept an ECD kidney, and this proportion steadily increased until 2014 when, for the first time, more patients were willing than unwilling to accept an ECD or KDPI-above-85% kidney. However, in 2015 this proportion dropped to 47.8% (Figure KI 9). Candidates aged 65 years or older, whose rates of willingness were previously increasing, reported lower rates of willingness to accept these kidneys, at 64.9% in 2015, down from 67.3% in 2012; other age groups remained relatively stable (Figure KI 18). This trend is surprising in light of concern and early evidence that the new KAS will decrease rates of deceased donor transplant in older patients.

Figure KI 3
Distribution of adults waiting for kidney transplant by age
Figure KI 4
Distribution of adults waiting for kidney transplant by race
Figure KI 5
Distribution of adults waiting for kidney transplant by diagnosis
Figure KI 6
Distribution of adults waiting for kidney transplant by waiting time
Figure KI 8
Distribution of adults waiting for kidney transplant by time on dialysis
Figure KI 9
Distribution of adults waiting for kidney transplant by willingness to accept ECD or KDPI > 85% kidney
Figure KI 18
Adults willing to accept a kidney designated ECD or KDPI > 85% by age
Table KI 2
Characteristics of adults on the kidney transplant waiting list on December 31, 2005 and December 31, 2015

The 3-year outcomes for adults listed for transplant in 2012 show that only 20.1% had undergone deceased donor transplant; an additional 15.3% had undergone living donor transplant, 18.5% died or were removed from the list, and 45.9% were still waiting (Figure KI 15). Reflecting the worsening supply-demand ratio for allografts nationally, the percentages of adults who underwent deceased donor transplant within any given period have generally continued to decrease, with the notable exception of an increase over the past year in the proportion of patients undergoing transplant within 1 year of listing (Figure KI 16). This increase may reflect the bolus effect of the new KAS, discussed further in the pre- and post-KAS chapter. Great geographic variation remained in the percentages of candidates who underwent deceased donor transplant within a given period of time; the percentage who did so within 5 years varied from 7.8% to 82.7% across donation service areas (DSAs) (Figure KI 17).

Figure KI 15
Three-year outcomes for adults waiting for kidney transplant, new listings in 2012
Figure KI 16
Percentage of adults who underwent deceased donor kidney transplant within a given time period of listing
Figure KI 17
Percentage of adults who underwent deceased donor kidney transplant within 5 years of listing in 2010 by DSA

Examining rates of deceased donor transplant among waitlisted candidates by candidate characteristics shows several marked changes in the setting of the new KAS: The deceased donor transplant rate among candidates aged 18 to 34 years jumped from 16.9 per 100 waitlist years in 2014 to 25.0 in 2015. Rates also increased, although less dramatically, for candidates aged 35 to 49 years. Correspondingly, the rate of transplants per 100 waitlist years decreased among candidates aged 65 years or older, from 19.9 to 16.8 per 100 waitlist years (Figure KI 11). Similarly, the rate for candidates with panel-reactive antibodies/calculated panel-reactive antibodies (CPRA) above 98% increased from 7.2 to 27.3 per 100 waitlist years, and rates decreased for those with CPRA 80% to 97%, from 34.4 to 23.0 per 100 waitlist years (Figure KI 13). The rate among patients with kidney failure due to diabetes has continued to fall, despite these candidates representing an increasing proportion of the waiting list.

Figure KI 11
Deceased donor kidney transplant rates among active adult waitlist candidates by age
Figure KI 13
Deceased donor kidney transplant rates among active adult waitlist candidates by C/PRA

Given increased waiting times and longer time on dialysis, one would expect waitlist mortality to increase correspondingly. However, overall pretransplant mortality rates decreased steadily until 2012 and remained relatively stable since then across age, race, and pretransplant diagnosis, with higher rates among older candidates and candidates with diabetes (Figure KI 19, Figure KI 20, Figure KI 21). Pretransplant mortality rates continued to show substantial geographic variation, mirroring the variation in waiting times; rates in some DSAs were more than twice the rates in others (Figure KI 22).

Figure KI 19
Pretransplant mortality rates among adults waitlisted for kidney transplant by age
Figure KI 20
Pretransplant mortality rates among adults waitlisted for kidney transplant by race
Figure KI 21
Pretransplant mortality rates among adults waitlisted for kidney transplant by diagnosis
Figure KI 22
Pretransplant mortality rates among adults waitlisted for kidney transplant in 2015, by DSA

2.2 Deceased Donation

Overall, the demographic characteristics of deceased donors have remained relatively stable over 10 years (Figure KI 24, Figure KI 25). Deceased donation per 100 deaths remained variable by state, from 7.4 to 29.3 per 100 deaths (Figure KI 26). Kidneys recovered from donors aged 50 to 64 and 65 years or older continued to be discarded at a high rate (32.9% and 62.3%, respectively), as were those from donors with diabetes (45.1%), hypertension (36.6%) and terminal creatinine above 1.5 mg/dL (36.3%), and donors who died of cerebrovascular accident (29.6%) (Figure KI 27, Figure KI 28, Figure KI 29, Figure KI 30, Figure KI 32). The discard rate for biopsied kidneys remained high at 31.4% compared with 6.8% for non-biopsied kidneys, despite lack of evidence that biopsy findings predict outcomes beyond the kidney donor risk index (KDRI)1,2 (Figure KI 31). Given varied practice regarding whether a kidney biopsy is performed (e.g., routine, patient characteristics, cause of death), more prospective research is needed to determine whether information from kidney biopsies increases the predictive ability of the KDRI, or causes unnecessary discards. Discard rates remained similar fordonation after brain death (DBD) and donation after circulatory death (DCD) (Figure KI 33), but were markedly higher for KDPI-above-85% kidneys than for kidneys with KDPI 85% or below (59.1% vs. 2.3%–17.8%, Figure KI 34). In addition, the discard rate for KDPI-above-85% kidneys was trending up, from 54.4% in 2012 to 59.1% in 2015. Presumably, some kidneys previously transplanted when labeled as standard criteria donor are now more commonly discarded given their higher KDPI score. If this trend continues, it will warrant closer examination.

Figure KI 24
Deceased kidney donors by age
Figure KI 25
Deceased kidney donors by race
Figure KI 26
Deceased donor kidney donation rates (per 1000 deaths) by state, 2012–2014
Figure KI 27
Rates of kidneys recovered for transplant and not transplanted by age
Figure KI 28
Rates of kidneys recovered for transplant and not transplanted by diabetes status
Figure KI 29
Rates of kidneys recovered for transplant and not transplanted by hypertension status
Figure KI 30
Rates of kidneys recovered for transplant and not transplanted by terminal creatinine
Figure KI 31
Rates of kidneys recovered for transplant and not transplanted by biopsy status
Figure KI 32
Rates of kidneys recovered for transplant and not transplanted by cause of death
Figure KI 33
Rates of kidneys recovered for transplant and not transplanted by DCD status
Figure KI 34
Rates of kidneys recovered for transplant and not transplanted by KDPI

Regarding specific components of the KDRI, an increasing proportion of donors weighed more than 80 kg, 45.3% in 2015 from 39.5% in 2005; the proportion of DCD kidneys increased from 7.3% in 2005 to 17.7% in 2015; and deaths from cerebrovascular accident decreased from 38.2% to 24.9% over 10 years (Figure KI 35). Average KDRI has been fairly stable over the past 10 years, between 1.20 and 1.24 (Figure KI 36). Anoxia as a cause of death has continued its marked increase, overtaking head trauma as the most common cause at 37.4% of donors (Figure KI 37).

Figure KI 35
Donor-specific components of the kidney donor risk index
Figure KI 36
Average kidney donor risk index
Figure KI 37
Cause of death among deceased kidney donors

2.3 Living Donation

In 2015, 5626 living donor transplants were performed, slightly up from 5539 in 2014 but well below the peak of 6647 in 2004. This decline appears to be due to a decrease in related kidney donations, as unrelated donation counts have generally been stable. The number of paired donations has increased, possibly accounting for some of the decrease in related donations as family members donate to an unrelated match; however, this increase has not been enough to offset the overall decline in related donations (Figure KI 38). In addition, with an ever growing waiting list, one would hope that the total number of living donor kidney transplants would increase proportionally, rather than the opposite. The proportion of kidney donors aged 50 to 64 years has been increasing over 10 years, from 20.3% in 2005 to 29.5% in 2015, for the first time outnumbering donors aged 18 to 34 years, 27.5%. Women made up an increasing majority of living donors at 63.5%, up from 59.2% in 2005 (Figure KI 40). The proportion of black donors has continued to decline over 10 years from 13.4% to 9.6%. The laparoscopic approach is increasingly the most common procedure type, more than 97% of procedures, assisted and unassisted in 2015. The data for rehospitalizations after living donation continued to show low rates of 2.5%, 3.9%, and 5.2% at 6 weeks, 6 months, and 12 months; however, these numbers were exceeded by the number of living donors for whom rehospitalization data were unknown, at 2.5%, 10.9%, and 21.0% at 6 weeks, 6 months and 12 months, respectively, highlighting a need for improved monitoring of living kidney donor outcomes (Figure KI 43). The number of living donors who reported a complication was slightly higher, 5.3%, 7.2%, and 8.8% at 6 weeks, 6 months, and 12 months, again with a relatively high unknown rate (Figure KI 44). The distribution of BMI remained relatively stable over 10 years, with a slight decrease in the proportion of donors with BMI 35 kg/m2 or higher, from 4.6% to 2.6%, and an increase in the proportion with BMI 30 to less than 35 kg/m2, from 16.1% to 19.5% (Figure KI 45). Collection of BMI data also improved, from 9.8% to 0.5% missing, which could partly explain the changing distribution. From 2011 to 2015, 17 deaths within 1 year of donation were reported to OPTN. The most common causes of death were medical (including donation-related) in seven and accident/homicide in five living donors.

Figure KI 38
Kidney transplants from living donors by donor relation
Figure KI 40
Living kidney donors by sex
Figure KI 43
Rehospitalization in the first 6 weeks, 6 months, and 1 year among living kidney donors, 2010–2014
Figure KI 44
Kidney complications among living kidney donors, 2010–2014
Figure KI 45
BMI among living kidney donors

2.4 Transplant

In total, 18,597 adult and pediatric kidney transplants, including multi-organ transplants, were performed in the US in 2015 (Figure KI 46), up from 17,388 in 2005; 30.3% of these were living donor transplants. As mentioned, the increase is attributable to an increase in deceased donation, as the number of living donor kidney transplants fell. After increasing over 10 years, the number of transplants among adults aged 65 years or older fell in 2015 compared with 2014 (Figure KI 47), a decrease entirely attributable to fewer deceased donor transplants; living donor transplants in this age group increased from 753 in 2014 (2014 Annual Data Report, Kidney Chapter) to 824 in 2015 (Table KI 6). Transplants remained more common in men than in women (Figure KI 48). Numbers of black and Hispanic recipients, having increased slowly over the previous 10 years, increased more noticeably in 2015 (Figure KI 49), and the number of transplants in recipients with hypertension also increased more in 2015 than in previous years (Figure KI 50). Perhaps mirroring the higher rate of discarded kidneys with KDPI above 85%, the proportion of deceased donor transplants using KDPI-above-85% kidneys fell slightly, a trend that should be monitored in future years.

Figure KI 46
Total kidney transplants
Figure KI 47
Total kidney transplants by age
Figure KI 48
Total kidney transplants by sex
Figure KI 49
Total kidney transplants by race
Figure KI 50
Total kidney transplants by diagnosis
Table KI 6
Characteristics of adult kidney transplant recipients, 2015

Previous trends in medication use at discharge continued in 2015. T-cell depleting agents were increasingly the induction agent of choice (Figure KI 52), tacrolimus and mycophenylate use continued to rise and exceeded 93% of all transplants (Figure KI 53, Figure KI 54), and mTor inhibitor use continued to decline to less than 5% (Figure KI 55). Despite interest in steroid-sparing regimens, a majority (70%) of transplant recipients remain on steroids at 1 year posttransplant (Figure KI 56).

Figure KI 52
Induction agent use in adult kidney transplant recipients
Figure KI 53
Calcineurin inhibitor use in adult kidney transplant recipients
Figure KI 54
Anti-metabolite use in adult kidney transplant recipients
Figure KI 55
mTOR inhibitor use in adult kidney transplant recipients
Figure KI 56
Steroid use in adult kidney transplant recipients

The proportion of transplants among deceased donor kidney recipients with CPRA 98% to 100% jumped from 4.8% in 2014 to 14.6% in 2015, nearly double the proportion of recipients with CPRA 80% to 97% (Figure KI 57). In 2011–2015, 4, 5, and 6 HLA mismatches were more common in deceased donor transplants, while 1, 2, and 3 HLA mismatches were more common in living donor transplants (Figure KI 59, Table KI 6).

Figure KI 57
C/PRA at time of kidney transplant in adult deceased donor recipients
Figure KI 59
Total HLA A, B, and DR mismatches among adult kidney transplant recipients, 2011–2015

2.5 Outcomes

The number of kidney transplant recipients alive with a functioning graft exceeded 200,000 in June 2015 (Figure KI 74), more than doubling since 2000 (Figure KI 6.8, 2012 Annual Data Report). While graft function and survival remained better for living than for deceased donor transplants, long-term outcomes continued to improve for both. All-cause and death-censored graft failure at 1, 3, 5, and 10 years continued to decline for both living and deceased donor transplants. For deceased donor transplants, 10-year graft failure for transplants in 2005 was 52.8%, down from 59.2% 10 years prior (Figure KI 60, Figure KI 61). Similarly, 10-year graft failure for living donor transplants in 2005 was 37.3%, down from 44.8% 10 years prior (Figure KI 63, Figure KI 64). Death with a functioning graft remained fairly constant for both living and deceased donor transplants (Figure KI 62, Figure KI 65). Five-year deceased donor graft survival was lowest for patients with diabetes or hypertension as a cause of kidney failure, at 70.4% and 71.8% (Figure KI 66), and with higher KDPI (57.6%, KDPI > 85%; 73.3%, KDPI 35–85%) (Figure KI 67). Five-year graft survival was essentially identical for DCD and DBD kidneys (Figure KI 68). Among living donor recipients, 5-year graft survival was lowest for those aged 65 years or older (Figure KI 69). Five-year graft survival was nearly 10% lower for black recipients than for Asian recipients (81.1% vs. 90.2%, Figure KI 70).

Figure KI 60
Graft failure among adult deceased donor kidney transplant recipients
Figure KI 61
Death-censored graft failure among adult deceased donor kidney transplant recipients
Figure KI 62
Death with function among adult deceased donor kidney transplant recipients
Figure KI 63
Graft failure among adult living donor kidney transplant recipients
Figure KI 64
Death-censored graft failure among adult living donor kidney transplant recipients
Figure KI 65
Death with function among adult living donor kidney transplant recipients
Figure KI 66
Graft survival among adult deceased donor kidney transplant recipients, 2010, by diagnosis
Figure KI 67
Graft survival among adult deceased donor kidney transplant recipients, 2010, by KDPI
Figure KI 68
Graft survival among adult deceased donor kidney transplant recipients, 2010, by DCD status
Figure KI 69
Graft survival among adult living donor kidney transplant recipients, 2010, by age
Figure KI 70
Graft survival among adult living donor kidney transplant recipients, 2010, by race
Figure KI 74
Recipients alive with a functioning kidney graft on June 30 of the year, by age at transplant

Proportions of recipients with estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73m2 at the time of discharge increased over the past 10 years (Figure KI 72); however, eGFR at 6 months was stable or improved; only 5% had an eGFR below 30 mL/min/1.73m2 (Figure KI 73), suggesting that recipients were discharged sooner or that higher-risk kidneys with delayed graft function were transplanted without a resulting decline in later eGFR. The incidence of acute rejection within the first year also decreased for both living and deceased donor transplant recipients (Figure KI 75), from 10% in 2009–2010 recipients to 7.9% in 2013–2014 recipients. The reported incidence of posttransplant lymphoproliferative disorder remained low, 0.6% at 5 years, but 3 times higher for candidates who were Epstein Barr virus-negative at transplant, but incidence may be underreported. Five-year patient survival for recipients of a deceased donor kidney in 2010 was 86.8%, but decreased with increasing age (75.2% for ages ≥ 65 years), and was lower for recipients with diabetes as cause of kidney failure (82.1%) and recipients of a KDPI above 85% kidney (78.5%) (Figure KI 79, Figure KI 80, Figure KI 81). Five-year survival among recipients of a living donor kidney in 2010 was 93.5%; while lower among older recipients and those with diabetes as cause of kidney failure, it remained 83.9% for recipients aged 65 years or older and 88.3% for recipients with diabetes as the cause of kidney disease (Figure KI 82, Figure KI 83, Figure KI 84).

Figure KI 72
Distribution of eGFR at discharge among adult kidney transplant recipients
Figure KI 73
Distribution of eGFR at 6 months posttransplant among adult kidney transplant recipients
Figure KI 75
Incidence of acute rejection by 1 year posttransplant among adult kidney transplant recipients by donor type
Figure KI 79
Patient survival among adult deceased donor kidney transplant recipients, 2010, by age
Figure KI 80
Patient survival among adult deceased donor kidney transplant recipients, 2010, by diagnosis
Figure KI 81
Patient survival among adult deceased donor kidney transplant recipients, 2010, by KDPI
Figure KI 82
Patient survival among adult living donor kidney transplant recipients, 2010, by age
Figure KI 83
Patient survival among adult living donor kidney transplant recipients, 2010, by diagnosis
Figure KI 84
Patient survival among adult living donor kidney transplant recipients, 2010, by race

3 Pediatric Kidney Transplant

3.1 Waiting List

In 2015, 928 pediatric candidates were added to the kidney transplant waiting list, 525 as inactive (Figure KI 85). The number of prevalent pediatric candidates (on the list on December 31 of the given year) has been steadily increasing and reached a peak of 1509 on December 31, 2015. The most common reason for inactive status among newly listed candidates in 2015 was incomplete work-up (47.3%), followed by living donor candidate status (16.8%), and too well to need transplant (11.4%) (Table KI 9). Over the past decade, the age of waitlisted pediatric candidates has shifted, with an increase in those aged 1 to 5 years (13.8% to 23.2%) and a decrease in those aged 11 to 17 years (69.9% to 57.0%) (Table KI 10). Proportions of candidates with congenital anomalies of the kidney and urinary tract (CAKUT) as primary cause of disease increased from 27.7% in 2005 to 38.9% in 2015, and proportions with glomerulonephritis decreased from 13.5% to 7.4%. Regarding sensitization, most candidates (64.8%) had a CPRA at the time of listing of 0%. Multi-organ listing was uncommon; only 2.4% of pediatric candidates were awaiting multi-organ transplant in 2015. The leading cause of end-stage kidney disease changed with age; CAKUT was most common in children aged younger than 6 years, while focal segmental glomerulosclerosis and glomerulonephritis were more common in older children (Figure KI 92).

Figure KI 85
New pediatric candidates added to the kidney transplant waiting list
Figure KI 92
Primary cause of ESRD in pediatric candidates waiting for kidney transplant by age, 2011–2015
Table KI 9
Reasons for inactive status among new pediatric kidney transplant listings, 2015
Table KI 10
Characteristics of pediatric candidates on the kidney transplant waiting list on December 31, 2005 and December 31, 2015

Of pediatric candidates removed from the waiting list in 2015, 62.0% received a deceased donor kidney, 27.6% received a living donor kidney, 2.1% died, 1.3% were considered too sick to undergo transplant, and 0.8% were removed from the list because their condition improved (Table KI 12). Among patients newly listed in 2012, 55.2% underwent deceased donor transplant within 3 years, 24.2% underwent living donor transplant, 16.3% were still waiting, 2.5% were removed from the list for other reasons, and 1.8% died (Figure KI 93). The rate of deceased donor transplant in 2015 among pediatric waitlisted candidates was 98.3 per 100 active waitlist years (Figure KI 94), compared with 18.8 for adult candidates (Figure KI 11). The intent of the new KAS is to maintain this high level of access to transplant for pediatric patients. Transplant rates varied by age. In 2015, transplant rates were highest for candidates aged 6 to 10 years (117.2 per 100 active waitlist years), followed by candidates ages 11 to 17 years (106.5). For the first time in several years, transplant rates among pediatric candidates were lowest for children aged younger than 6 years (93.4 per 100 active waitlist years). Rates also varied by CPRA and demonstrate the effects of new priority for highly sensitized candidates under the KAS. For pediatric candidates with CPRA greater than 98%, the transplant rate increased from 6.9 per 100 active waitlist years in 2014 to 20.3 in 2015. Transplant rates for pediatric candidates with a CPRA of 80% to 97% declined from 63.7 to 18.2. In contrast to mortality among candidates waiting for other organs, pretransplant mortality among pediatric candidates waiting for kidney transplant was low: 1.3 per 100 waitlist years in 2014–2015 (Figure KI 96).

Figure KI 93
Three-year outcomes for newly listed pediatric candidates waiting for kidney transplant, 2012
Figure KI 94
Deceased donor kidney transplant rates among active pediatric waitlist candidates by age
Figure KI 96
Pretransplant mortality rates among pediatrics waitlisted for kidney transplant by age
Table KI 12
Removal reason among pediatric kidney transplant candidates

3.2 Transplant

The number of pediatric kidney transplants decreased from a peak of 899 in 2005 to 718 in 2015 (Figure KI 97). The decline in the proportion of living donor kidney transplants in pediatric recipients is of concern. In 2015, only 33.7% of pediatric transplants were from living donors, compared with 50.1% in 2004. Regarding the source of the living donor, the number of related donors has decreased dramatically. Children aged younger than 6 years were most likely to receive a living donor kidney (47.3%) (Figure KI 99). In 2015, 37 centers were performing only pediatric kidney transplants, compared with 133 performing only adult transplants and 54 performing transplants in both adults and children (Figure KI 100). Regarding donor source and age at transplant, a higher proportion of living donor transplants were in recipients aged 1 to 5 years; this group accounted for 30.8% of pediatric living donor transplants and 19.2% of pediatric deceased donor transplants, compared with 20.0% and 18.9%, respectively, for recipients aged 6 to 10 years. While the majority of pediatric transplants were in recipients aged 11 to 17 years, deceased donor transplants were more common than living donor transplants (61.7% vs. 48.8%). (Table KI 13). The racial distribution differed among deceased and living donor transplant recipients. A higher proportion of living donor recipients were white (70.5% vs. 39.7%) and a higher proportion of deceased donor recipients were black (25.4% vs. 9.1%) and Hispanic (27.4% vs. 15.0%). Private insurance was more common among living donor recipients and Medicare/Medicaid was more common among deceased donor recipients. Most deceased donor recipients (65.4%) underwent transplant with a kidney from a donor with KPDI less than 20%. No ABO incompatible transplants occurred in pediatric kidney recipients in 2015. The number of HLA mismatches was higher among deceased donor recipients than among living donor recipients; 83.5% of deceased donor recipients and 24.1iving donor recipients had more than three HLA mismatches in 2013–2015.

Figure KI 97
Pediatric kidney transplants by donor type
Figure KI 99
Percent of pediatric kidney transplants from living donors by recipient age
Figure KI 100
Number of centers performing pediatric and adult kidney transplants by center's age mix
Table KI 13
Characteristics of pediatric kidney transplant recipients, 2013–2015

The combination of a donor who was positive for cytomegalovirus and a pediatric recipient who was negative occurred in 29.4% of deceased donor transplants and in 25.1% of living donor transplants (Table KI 14 and Table KI 15). The combination of a donor who was positive for Epstein-Barr virus (EBV) and a recipient who was negative occurred in 36.5% of deceased donor transplants and in 44.7% of living donor transplants.

Table KI 14
Pediatric deceased donor kidney donor-recipient serology matching, 2011–2015
Table KI 15
Pediatric living donor kidney donor-recipient serology matching, 2011–2015

3.3 Immunosuppressive Medication Use

Trends in immunosuppressive medications used in children and adolescents were similar to trends for adults. In 2015, the use of T-cell depleting agents continued to increase, reaching 61.6%; interleukin-2 receptor antagonist (IL-2-RA) therapy use remained steady at 33.3%. The percentage of recipients receiving no induction therapy continued to decline, reaching a low of 9.1% in 2015 (Figure KI 101). In 2015, tacrolimus was used as part of the initial maintenance immunosuppressive medication regimen in 96.3% of pediatric transplant recipients and mycophenolate in 93.2%. Mammalian target of rapamycin inhibitors were used in 7.7% of 2014 pediatric recipients at 1 year posttransplant. Corticosteroids were used in 59.9% of 2015 pediatric recipients at the time of transplant and in 64.1% of 2014 recipients at 1 year posttransplant. Regarding induction use by CPRA, T-cell depleting agents were more common with increasing CPRA and IL-2-RA use more common with decreasing CPRA (Figure KI 106).

Figure KI 101
Induction agent use in pediatric kidney transplant recipients
Figure KI 106
Induction use by CPRA among pediatric kidney transplant recipients, 2011–2015

3.4 Outcomes

All-cause graft failure after deceased donor transplant in pediatric recipients was 2.8% at 6 months and 3.7% at 1 year for transplants in 2014–2015, 10.4% at 3 years for transplants in 2012–2013, 18.0% at 5 years for transplants in 2010–2011, and 51.9% at 10 years for transplants in 2004–2005 (Figure KI 110). Corresponding graft failure after living donor transplant was 2.7% at 6 months and 3.5% at 1 year for transplants in 2014–2015, 4.7% at 3 years for transplants in 2012–2013, 11.1% at 5 years for transplants in 2010–2011, and 34.8% at 10 years for transplants in 2004–2005 (Figure KI 113). For a cohort of recipients who underwent transplant in 2006–2010, graft survival was highest for living donor recipients aged younger than 11 years (89.1% at 5 years) and lowest for deceased donor recipients aged 11 to 17 years (72.0% at 5 years) (Figure KI 116). By age, incidence of reported acute rejection in the first posttransplant year was highest for recipients aged 11 to 17 years, at 12.4% for patients who underwent transplant in 2013–2014, compared with 10.3% among recipients aged younger than 6 years and 8.7% among recipients aged 6 to 10 years (Figure KI 117). Short-term renal function, measured by eGFR, improved substantially over the past decade. The proportion of recipients with an eGFR of 90 mL/min/1.73 m2 or higher at discharge increased from 20.7% in 2005 to 32.2% in 2015, and at 1 year posttransplant, from 13.0% to 28.5% (Figure KI 108). Of recipients in the 2014 cohort, 72.5% had chronic kidney disease stage 1–2 at 1 year posttransplant, with an eGFR of 60 mL/min/1.73m2 or higher. The incidence of posttransplant lymphoproliferative disorder among EBV-negative recipients was 3.2% at 5 years posttransplant, compared with 0.7% among EBV-positive recipients (Figure KI 118). Overall 5-year patient survival among pediatric kidney transplant recipients in 2006–2010 was 97.7%.

Figure KI 108
Distribution of eGFR at discharge among pediatric kidney-alone transplant recipients
Figure KI 110
Graft failure among pediatric kidney-alone deceased donor transplant recipients
Figure KI 113
Graft failure among pediatric living donor kidney-alone transplant recipients
Figure KI 116
Graft survival among pediatric kidney transplant recipients by age and donor type, 2006–2010
Figure KI 117
Incidence of acute rejection by 1 year posttransplant among pediatric kidney transplant recipients by age
Figure KI 118
Incidence of PTLD among pediatric kidney transplant recipients by recipient EBV status at transplant, 2003–2013
Figure KI 7
Distribution of adults waiting for kidney transplant by C/PRA
Figure KI 10
Prevalent dialysis patients waitlisted for kidney transplant by age
Figure KI 12
Deceased donor kidney transplant rates among active adult waitlist candidates by diagnosis
Figure KI 14
Deceased donor kidney transplant rates among active adult waitlist candidates by blood type
Figure KI 39
Living kidney donors by age
Figure KI 41
Living kidney donors by race
Figure KI 42
Intended living kidney donor procedure type
Figure KI 51
Kidney transplants by kidney donor profile index (KDPI)
Figure KI 58
C/PRA at time of kidney transplant in adult living donor recipients
Figure KI 71
Graft survival among adult living donor kidney transplant recipients, 2010, by diagnosis
Figure KI 76
Posttransplant diabetes among adult kidney transplant recipients
Figure KI 77
Posttransplant diabetes within 1 year among adult kidney transplant recipients by BMI at transplant
Figure KI 78
Incidence of PTLD among adult kidney transplant recipients by recipient EBV status at transplant, 2009–2013
Figure KI 86
Pediatric candidates listed for kidney transplant on December 31 each year
Figure KI 87
Distribution of pediatric candidates waiting for kidney transplant by age
Figure KI 88
Distribution of pediatric candidates waiting for kidney transplant by race
Figure KI 89
Distribution of pediatric candidates waiting for kidney transplant by diagnosis
Figure KI 90
Distribution of pediatric candidates waiting for kidney transplant by waiting time
Figure KI 91
Distribution of pediatric candidates waiting for kidney transplant by PRA
Figure KI 95
Deceased donor kidney transplant rates among active pediatric waitlist candidates by C/PRA
Figure KI 98
Pediatric kidney transplants from living donors by relation
Figure KI 102
Calcineurin inhibitor use in pedatric kidney transplant recipients
Figure KI 103
Anti-metabolite use in pedatric kidney transplant recipients
Figure KI 104
mTOR inhibitor use in pediatric kidney transplant recipients
Figure KI 105
Steroid use in pedatric kidney transplant recipients
Figure KI 107
Total HLA A, B, and DR mismatches among pediatric kidney transplant recipients, 2011–2015
Figure KI 109
Distribution of eGFR at 12 months posttransplant among pediatric kidney-alone transplant recipients
Figure KI 111
Death-censored graft failure among pediatric deceased donor kidney-alone transplant recipients
Figure KI 112
Death with function among pediatric deceased donor kidney-alone transplant recipients
Figure KI 114
Death-censored graft failure among pediatric living donor kidney-alone transplant recipients
Figure KI 115
Death with function among pediatric living donor kidney-alone transplant recipients
Figure KI 119
Patient survival among pediatric kidney transplant recipients, 2006–2010, by age and donor type
Table KI 5
Living kidney donor deaths, 2011–2015, by number of days after donation
Table KI 7
Adult deceased donor kidney donor-recipient serology matching, 2011–2015
Table KI 8
Adult living donor kidney donor-recipient serology matching, 2011–2015
Table KI 11
Kidney transplant waitlist activity among pediatric candidates

Acknowledgments

The publication was produced for the U.S. Department of Health and Human Services, Health Resources and Services Administration, by the Minneapolis Medical Research Foundation (MMRF) and by the United Network for Organ Sharing (UNOS) under contracts HHSH250201500009C and 234-2005-37011C, respectively.

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Suggested Citations Full citation: Organ Procurement and Transplantation Network (OPTN) and Scientific Registry of Transplant Recipients (SRTR). OPTN/SRTR 2015 Annual Data Report. Rockville, MD: Department of Health and Human Services, Health Resources and Services Administration; 2016. Abbreviated citation: OPTN/SRTR 2015 Annual Data Report. HHS/HRSA.

Publications based on data in this report or supplied on request must include a citation and the following statement: The data and analyses reported in the 2015 Annual Data Report of the U.S. Organ Procurement and Transplantation Network and the Scientific Registry of Transplant Recipients have been supplied by the United Network for Organ Sharing and the Minneapolis Medical Research Foundation under contract with HHS/HRSA. The authors alone are responsible for reporting and interpreting these data; the views expressed herein are those of the authors and not necessarily those of the U.S. Government.