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OPTN/SRTR 2022 Annual Data Report: Kidney

OPTN/SRTR 2022 Annual Data Report: Kidney

Krista L. Lentine1,2, Jodi M. Smith1,3, Grace R. Lyden1,4, Jonathan M. Miller1,4, Thomas G. Dolan5, Keighly Bradbrook5, Lindsay Larkin5, Kayla Temple5, Dzhuliyana K. Handarova5, Samantha Weiss5, Ajay K. Israni1,4,6, Jon J. Snyder1,4,6

1Scientific Registry of Transplant Recipients, Hennepin Healthcare Research Institute, Minneapolis, MN

2SSM Health Saint Louis University Hospital Transplant Center, Saint Louis University School of Medicine, St. Louis, MO

3Department of Pediatrics, University of Washington, Seattle, WA

4Department of Medicine, Hennepin Healthcare, University of Minnesota, Minneapolis, MN

5Organ Procurement and Transplantation Network, United Network for Organ Sharing, Richmond, VA

6Department of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN

Abstract

The year 2022 had continued successes and challenges for the field of kidney transplantation, as the community adapted to ongoing surges of the COVID-19 pandemic and broader geographic organ distribution. The total number of kidney transplants in the United States reached a record count of 26,309, driven by continued growth in deceased donor kidney transplants (DDKTs). The total number of candidates listed for DDKT rose slightly in 2022 but remained below 2019 listing levels, with 12.4% of candidates having been waiting 5 years or longer. Following the height of the COVID-19 pandemic, pretransplant mortality in 2022 declined across age, race and ethnicity, sex, and blood type groups. Pretransplant mortality continued to vary substantially by donation service area. The proportion of deceased donor kidneys recovered but not used for transplant (nonuse rate) rose to a high of 26.7% overall, with greater nonuse of biopsied kidneys (39.8%), kidneys from donors aged 55 years or older (54.7%), and kidneys with a kidney donor profile index (KDPI) of 85% or greater (71.3%). Nonuse of kidneys from donors who are hepatitis C virus (HCV) antibody positive rose to 30.2% but only slightly exceeded that of HCV antibody–negative donors. Disparities in access to living donor kidney transplant (LDKT) persist, especially for non-White and publicly insured patients. Delayed graft function continues an upward trend and occurred in 26.3% of adult kidney transplants in 2022. Five-year graft survival after LDKT compared with DDKT was 90.0% versus 81.4% for recipients aged 18-34 years and 80.8% versus 67.8% for recipients aged 65 years or older, respectively. The total number of pediatric kidney transplants performed in 2022 decreased to 705, its lowest point in the past decade; 502 (71.2%) were DDKTs and 203 (28.8%) were LDKTs. Among pediatric recipients, LDKT remains low, with continued racial disparities. The rate of DDKT among pediatric candidates has decreased by almost 25% since 2011. Congenital anomalies of the kidney and urinary tract remain the leading primary kidney disease diagnosis among pediatric candidates with a reported diagnosis. Most pediatric deceased donor recipients received a kidney from a donor with a KDPI of less than 35%. The rate of delayed graft function was 5.8% in 2022 and has been stable over the past decade. Long-term graft survival continues to improve, with superior outcomes for living donor transplant recipients.

Keywords: Deceased donor transplant, kidney transplantation, living donor transplant, transplant access, transplant outcomes, waitlist outcomes

1 Introduction

While kidney transplant provides eligible patients with end-stage kidney disease the best opportunity for long-term, dialysis-free survival at the lowest cost to the health care system,1 maximizing transplant access, reducing access disparities, and optimizing long-term allograft survival are ongoing challenges. National urgencies to increase access to kidney transplant are receiving unprecedented attention from the federal government, ranging from the Executive Order on Advancing American Kidney Health2 to ongoing regulatory and legislative actions directed at increasing deceased donor organ procurement and organ use, removing barriers to living donation, and overall transplant system modernization to improve performance and efficiencies. Surges of the COVID-19 pandemic continued to affect transplant practice in 2022, as the community approached a transition from navigating the public health emergency to managing an endemic infection. While kidney transplant from deceased donors continues to rise, this success is challenged by an ongoing increase in kidney nonuse rates, along with continued increases in cold ischemia times and delayed graft function in the context of broader geographic organ sharing. Only a small proportion of kidney transplant candidates receive living donor allografts, at static rates characterized by sociodemographic disparities. The Annual Data Report provides an opportunity to assess the state of kidney transplantation and examine successes along with concerning trends that warrant further monitoring and evaluation. Data on US adult and pediatric kidney transplant waiting lists, deceased and living donation, transplants, and outcomes are provided.

2 Adult Kidney Transplant

2.1 Waiting List

The number of adult candidates added to the kidney waiting list during the year 2022 rose to a high of 44,187, reflecting ongoing recovery from the COVID-19 pandemic–related decline to 37,400 in 2020 and exceeding the 2019 prepandemic waitlist addition peak of 42,932 (Figure KI 1). The total number of adult candidates listed for kidney transplant (including multiple listings for those listed at more than one center) rose slightly to 140,165, compared with 139,011 in 2021, but remained below the 144,058 candidates listed in 2019 (Figure KI 2). There were 4,454 waitlist removals due to death in 2022, a notable decrease from 5,283 in 2021 during the COVID-19 pandemic; however, the 4,504 waitlist removals due to being too sick for transplant in 2022 reflect an increase from 4,058 in 2021, and waitlist removals for other reasons aside from transplant were also higher in 2022 (Table KI 5). The trend of a gradual increase in the age of candidates on the waiting list over the past decade persisted (Figure KI 3). Candidates aged 50-64 years at listing remained the largest age group (42.3% of listed candidates), while the proportion of candidates aged 65 years or older rose slightly to a high of 26.5% (Figure KI 3). The sex distribution of the waiting list was largely unchanged, with men making up 61.9% of kidney candidates (Figure KI 4). Since 2011, the proportions of Asian and Hispanic candidates on the kidney waiting list have gradually increased, accompanied by a decline in the proportion of White candidates, but the distribution in 2022 was stable compared with 2021 (Figure KI 5). The distribution of primary kidney failure diagnoses was stable in 2022, with diabetes (38.3%) and hypertension (20.4%) as the most common identified causes (Figure KI 6).

The proportion of candidates prevalent on the waiting list with waiting time less than 1 year rose to 36.1% in 2022, up from 34.2% in 2021 and 31.4% in 2020, while 12.4% on the waiting list at some point in 2022 have been waiting 5 years or longer, a proportion that has decreased in recent years (Figure KI 7). The proportion of waitlisted candidates with a high body mass index (BMI) also continued to increase slightly in 2022, with 18.9% having a BMI of 35 kg/m2 or greater, while a stable 27.4% had a BMI of 30 to less than 35 kg/m2 (Figure KI 8). Encouragingly, the proportion of candidates waitlisted before starting dialysis continued to increase, reaching 25.6% in 2022, although 15.9% of those waitlisted had been on dialysis for 6 or more years (Figure KI 9). The distribution of candidates across blood groups remained stable in 2022, with 52.6% of waitlisted kidney candidates having blood type O (Figure KI 10). The proportion of candidates with a previous transplant was 11.0% in 2022, reflecting a gradual decline from 15.0% in 2011 (Figure KI 11).

The proportion of candidates willing to accept a kidney with a high kidney donor profile index (KDPI) decreased slightly in all age groups in 2022 compared with 2021, continuing a decline after implementation of the revised kidney allocation system (KAS) in December 2014 (Figure KI 12). Only 49.0% of candidates aged 50-64 years and 63.9% of candidates aged 65 years or older were willing to accept these kidneys (Figure KI 12), even though patients aged 50 years and older have a lower rate of deceased donor kidney transplant (DDKT) under the current KAS compared with younger patients (Figure KI 15). Conversely, the proportion of candidates willing to accept a kidney from a donor who is hepatitis C virus (HCV) antibody positive continued to increase sharply, to 46.4% in 2022, correlating with availability of highly effective direct-acting antiviral agents and experience using these regimens to manage anticipated donor-derived infections (Figure KI 13).

Rates of DDKT among adult waitlisted candidates continued to increase in 2022, after a nadir in 2014 (Figure KI 14). Increased rates were noted across all age groups (Figure KI 15) and primary kidney disease diagnosis groups (Figure KI 17). Rates of DDKT rose across racial and ethnic groups, especially among Asian, Black, and Multiracial candidates, such that Black candidates had the highest DDKT rate among the groups in 2022 (22.3 per 100 patient-years) (Figure KI 16). Rates of DDKT among patients with calculated panel-reactive antibody (cPRA) levels of 80% and higher showed slight declines in 2022 compared with 2021, while DDKT rates among those with cPRA less than 1% rose from 19.8 to 21.4 per 100 patient-years (Figure KI 18). In 2022, DDKT rates were highest in those with cPRA levels of 80%-<98%, at 30.9 per 100 patient-years (Figure KI 18). Rates of DDKT rose across candidate blood groups in 2022, reaching a high of 39.0 per 100 patient-years in those with blood type AB (Figure KI 19). In 2022, DDKT rates increased across those with waiting times less than 5 years (Figure KI 20). Among those with 5 or more years of waiting time, the rate declined slightly to 19.2 per 100 patient-years, compared with 19.5 per 100 patient-years in 2021 (Figure KI 20). Rates of DDKT were similar between men and women in 2022, remaining slightly higher in women since 2016 (Figure KI 21).

For patients waitlisted in 2017-2019, 31.4% were still waiting 3 years after listing; 28.9% had undergone DDKT, 14.0% had undergone living donor kidney transplant (LDKT), 6.5% had died, and 19.2% were removed from the waiting list (Figure KI 22). The proportion of patients who underwent DDKT within 3 months rose to a high of 11.8% among those listed in 2021, while the percentage who underwent DDKT within 3 years also continued to increase (Figure KI 23).

Following the height of the COVID-19 pandemic, pretransplant mortality declined in 2022 to 5.4 deaths per 100 patient-years, compared with 6.2 per 100 patient-years in 2021 (Figure KI 24), with decreases across age (Figure KI 25), race and ethnicity (Figure KI 26), sex (Figure KI 27), and blood type groups (Figure KI 29). Considered by blood type, pretransplant mortality was lowest for those with type AB, the group with the highest DDKT rate (Figure KI 29). Pretransplant mortality declined in all diagnosis groups except glomerulonephritis (Figure KI 28), but those with glomerulonephritis or cystic kidney disease continued to have the lowest mortality rates (Figure KI 28). Pretransplant mortality continued to vary substantially by donation service area, from 1.8 to 7.5 deaths per 100 patient-years (Figure KI 30).

Death within 6 months of removal from the waiting list (for waitlist removal reasons other than transplant or death) declined in 2022 compared with 2021 (Figure KI 31), including among both women and men (Figure KI 35). Considered by diagnosis group, mortality after waitlist removal declined for those with diabetes, hypertension, and Other/unknown causes, but increased in those with cystic kidney disease or glomerulonephritis (Figure KI 32). By age, death within 6 months of waitlist removal rose slightly for candidates aged 65 years and older but declined in all other age groups (Figure KI 33). By race, death within 6 months of waitlist removal rose for Asian candidates, was stable for White candidates, and declined for Black, Hispanic, and especially Multiracial and Native American candidates (Figure KI 34).

2.2 Deceased Donation

The counts of deceased donors from whom at least one kidney was recovered for transplant continued to increase in 2022 (Figure KI 36), particularly among donors aged 30 years and older (Figure KI 37). The counts of HCV antibody–positive deceased donors from whom kidneys were recovered also rose in 2022 (Figure KI 38), although the proportion (10.5%) has been stable since 2019 (Figure KI 42). The racial and ethnic distribution of deceased kidney donors remained largely unchanged over the past decade (Figure KI 41), and the predominance of male deceased donors in 2022 (62.3%) was stable compared with 2021 (Figure KI 40). In 2022, the proportion of deceased kidney donors aged 29 years and younger declined compared with 2021, the proportion aged 30-54 years was stable, and the proportion aged 55 years and older increased (Figure KI 39). The proportion of deceased kidney donors who died of head trauma declined slightly in 2022, while the proportion with Other/unknown causes of death rose slightly in 2022 compared with 2021 (Figure KI 43).

Overall, the proportion of deceased donor kidneys recovered but not transplanted (nonuse rate) rose to a notable high of 26.7% in 2022 compared with 17.9% in 2011 (Figure KI 44), in the context of the broader geographic organ distribution and the continuing COVID-19 pandemic, but also varied substantially by donor characteristics. Nonuse rates were highest for kidneys recovered from donors aged 55 years or older, reaching 54.7% in 2022 (Figure KI 45). The nonuse rate was also higher in kidneys recovered from donors with diabetes, hypertension, or elevated BMI, compared to donors without each of these characteristics, respectively (Figure KI 46, Figure KI 49, and Figure KI 50). In 2022, the nonuse rate was slightly higher for kidneys recovered from Asian and Black donors (30.8% and 29.1%, respectively) compared with White donors (27.0%), while nonuse was lower for kidneys recovered from donors in the Hispanic and Other categories (Figure KI 48). Recovered kidneys from which biopsies were obtained continued to have rising nonuse rates, up to 39.8% in 2022 (Figure KI 52). The proportion of unused kidneys recovered from HCV antibody–positive donors declined sharply from 2013 to 2020, but increased to 30.2% in 2022 (Figure KI 54). A lower proportion of kidneys from donors with increased infection risk as defined by the US Public Health Service guidelines were not used compared with kidneys from donors with standard infection risk in 2022 (21.3% versus 27.9%) (Figure KI 55), perhaps because kidneys with increased infection risk are often from younger donors,3 and otherwise of high quality with low KDPI. In 2022, the nonuse rate of kidneys with a KDPI of 85% or greater reached a high of 71.3% (Figure KI 57), while the nonuse rate of kidneys from donation after circulatory death donors rose to 33.9% (Figure KI 56).

2.3 Living Donation

Following a rise in the number of LDKTs from 5,809 in 2017 up to 6,855 in 2019, LDKTs decreased to 5,226 in 2020 during the COVID-19 pandemic, partially recovered to 5,955 in 2021, and then slightly declined to 5,798 in 2022 (Figure KI 58). In 2022, among LDKTs performed, spousal donations increased and related donations declined, while direct, distantly related (defined as a biological relative other than a parent, child, full or half sibling) and paired kidney donations were stable compared with 2021, with 19.1% of LDKTs performed through donor exchanges (Figure KI 58). Only a small proportion of the waiting list receives an LDKT each year, despite government initiatives to reduce financial barriers to living donation and to encourage early LDKT.4

In 2022, the proportion of living kidney donors aged 40 years or older rose slightly, while the proportion aged 39 years and younger declined, with young adult living donors aged 18-29 years reaching a low of 12.9% (Figure KI 59). Living donors aged 40-54 years continued to make up the most common donor age group (Figure KI 59). In 2022, the proportion of living kidney donors who were women remained stably high, at 63.8% (Figure KI 60). The racial and ethnic composition of living donors in 2022 was relatively stable compared with 2021, including 69.4% White, 16.3% Hispanic, and 7.6% Black (Figure KI 61). Notably, this reflects a general decline in the proportion of Black living donors, from 11.9% in 2011 (Figure KI 61). The proportion of living donors who were obese, based on BMI greater than 30 kg/m2, was stable in 2022 compared with 2021, at 23.5% (Figure KI 63). Most donation surgeries began as laparoscopic hand assisted (59.9%) or pure laparoscopy (38.3%) (Figure KI 62).

2.4 Transplants

The upward trajectory in total kidney transplants (which includes adult and pediatric) was modestly slowed by the COVID-19 pandemic in 2020, then continued to rise through 2022, reaching a high of 26,309 (Figure KI 64). This trend was driven by growth in DDKTs, which rose to a high of 20,446 in 2022 (Figure KI 65), predominantly from donors with a KDPI of less than 85%. In 2022, the proportion of DDKTs from donors classified as KDPI less than 20% showed a slight but continued increase to 24.9%, while most DDKTs were from donors with KDPI of 35%-<85% (69.0%), and only 6.1% of DDKTs were from donors with KDPI of 85% or greater (Figure KI 70). Distributions of total kidney transplants in 2022 were similar to 2021 distributions across recipient sex, race and ethnicity, and cause of kidney disease groups (Figure KI 67, Figure KI 68, and Figure KI 69). Considered by recipient age, total transplant counts increased most in recipients aged 50-64 years, and especially in those aged 65 years and older (Figure KI 66). In 2022, 90.7% of adult DDKTs and 91.1% of adult LDKTs were performed in first-time recipients (Table KI 8).

Disparities in access to LDKT persist. While 31.7% of adult waitlisted candidates on December 31, 2022, were Black (Table KI 1), Black patients made up only 12.8% of LDKT recipients versus 34.1% of DDKT recipients that year (Table KI 6). White patients made up 35.5% of the waiting list (Table KI 1), while 61.4% of LDKT recipients and 35.3% of DDKT recipients were White (Table KI 6). Most adult LDKT recipients (54.5%) had private insurance at the time of transplant, compared with 26.9% of DDKT recipients (Table KI 6); 62.5% of DDKT recipients were Medicare beneficiaries compared with 37.6% of LDKT recipients (Table KI 6). LDKT recipients tended to have less dialysis time and lower cPRA levels than DDKT recipients (Table KI 7). In 2022, 33.3% of adult LDKT recipients underwent transplant without dialysis, compared with 12.1% of DDKT recipients (Table KI 7).

Induction immunosuppression was used in 92.1% of adult kidney transplants in 2022, a stable proportion compared with 2021 (Figure KI 71). Most patients received tacrolimus and mycophenolate mofetil (MMF)–based maintenance regimens at discharge, with use of triple therapy including steroids and use of tacrolimus-MMF (without reported steroid use) stable at 67.8% and 25.1%, respectively (Figure KI 72). As noted previously, the proportion of adult DDKT recipients with peak cPRA levels of 98%-100% increased sharply after the 2014 KAS revision and then gradually declined, from 12.5% in 2015 to 6.3% in 2020, and remained stable at 6.1% in 2022 (Figure KI 73). Following the March 2021 KAS250 revision, there was an increase in the proportion of DDKT recipients with cPRA levels of 80%-98%, from 7.0% in 2020 to 10.4% in 2021, followed by a slight decline to 9.2% in 2022 (Figure KI 73). By comparison, only 0.9% of LDKT recipients in 2022 had peak cPRA levels of 98%-100%, while most LDKT recipients (69.5%) had peak cPRA levels of less than 1% (Figure KI 74).

2.5 Outcomes

Delayed graft function, defined as dialysis within the first 7 days posttransplant, has trended up over the past decade, occurring in 26.3% of adult kidney recipients in 2022 (Figure KI 75). Estimated glomerular filtration rate (eGFR) at 12 months, calculated using the 2021 race-free Chronic Kidney Disease–Epidemiology Collaboration creatinine-based equation, an early surrogate of allograft outcome, was 45 mL/min/1.73 m2 or higher for 62.4% of DDKT recipients in 2021, reflecting a downtrend from 67.8% in 2016 (Figure KI 88). Among LDKT recipients, 79.8% had 12-month eGFR of 45 mL/min/1.73 m2 or higher in 2021, a slight decline from 82.6% in 2016 (Figure KI 89). For transplants performed in 2021, acute rejection by 1 year was highest in recipients aged 18-34 years at 8.8% and lowest in recipients aged 65 years or older at 5.4% (Figure KI 90). Acute rejection at 1 year occurred in 10.8% of those who received both interleukin 2 receptor antibody with T-cell–depleting induction (Figure KI 91), likely in part reflecting regimen changes in patients with early complications. Acute rejection at 1 year was reported in 7.0% who received only interleukin 2 receptor antibody, 6.0% who received only T-cell–depleting induction, and 4.7% of the small subgroup whose transplants were managed without induction (Figure KI 91). Posttransplant lymphoproliferative disorder was uncommon in 2011-2017 adult kidney transplant recipients, reported in 1.7% and 0.5% of Epstein Barr virus (EBV)–negative and EBV-positive recipients, respectively, at 5 years posttransplant (Figure KI 92).

Among 2015-2017 adult DDKT recipients, 5-year graft survival was lowest among older (versus younger) recipients, with 67.8% graft survival at 5 years among recipients aged 65 years and older compared with 81.4% graft survival at 5 years among recipients aged 18-34 years (Figure KI 76). Compared with graft survival among White recipients, 5-year DDKT graft survival was higher among Asian, Hispanic, and Multiracial recipients, but lower among Black and Native American recipients (Figure KI 77). Graft survival was lower among recipients with diabetes as the cause of kidney failure (versus other causes; Figure KI 79), and recipients with BMI of 30 kg/m2 or higher (versus BMI of 18.5-<25 kg/m2; Figure KI 83). Five-year DDKT graft survival was 64.0% for allografts with KDPI of 85% or greater, compared with 84.5%, 81.3%, and 75.4% for those with KDPI <20%, KDPI 20%-<35%, and KDPI 35%-<85%, respectively (Figure KI 80). Five-year graft survival did not differ for donation after circulatory death transplants compared with donation after brain death transplants (Figure KI 81). Graft survival was lower after transplant of kidneys that underwent a procurement biopsy compared to kidneys transplanted without biopsy (73.7% versus 81.2%, respectively; Figure KI 82), which likely reflects the donor characteristics of biopsied kidneys, including higher KDPI.5 Of note, the Organ Procurement and Transplantation Network implemented minimum kidney biopsy criteria in September 2022; this policy change states that organ procurement organizations “must make a reasonable effort to ensure that a procurement kidney biopsy is performed” for all adult donors meeting the listed criteria, including KDPI greater than 85%.6 Given the aforementioned high nonuse rate of biopsied kidneys, the utility of procurement biopsy in informing appropriate organ use is a topic of ongoing controversy.7

Among 2015-2017 adult LDKT recipients, 5-year graft survival was 80.8% in recipients aged 65 years or older, compared with 90.0% in recipients aged 18-34 years (Figure KI 84). Five-year LDKT graft survival was lower in recipients with diabetic kidney failure compared with those with other disease causes (Figure KI 87), and similar in women and men (Figure KI 86). Compared with graft survival among White recipients, 5-year LDKT survival was higher among Asian and Hispanic recipients and lower among Black, Multiracial, and Native American recipients (Figure KI 85).

Trends in adult posttransplant patient survival generally paralleled patterns of graft survival (Figure KI 93, Figure KI 94, Figure KI 95, Figure KI 96, Figure KI 97, Figure KI 98, Figure KI 99, Figure KI 100, and Figure KI 101). Five years posttransplant, 72.0% of DDKT recipients and 83.0% of LDKT recipients aged 65 years or older were alive, compared with 95.8% and 97.9% of those aged 18-34 years, respectively (Figure KI 93 and Figure KI 99). Patient survival after DDKT was higher in women than in men (Figure KI 95). Compared with patient survival among White recipients, 5-year patient survival after DDKT and LDKT was higher among Asian, Black, Hispanic, and Multiracial recipients, but lower among Native American recipients; however, across racial groups, patient survival was higher after LDKT compared with DDKT (Figure KI 94 and Figure KI 101). Five-year patient survival was lowest among recipients with diabetes as the cause of kidney disease, at 78.1% for DDKT recipients with diabetes and 85.9% for LDKT recipients with diabetes (Figure KI 96 and Figure KI 100). Patient survival was also lower among DDKT recipients who received kidneys with a KPDI of 85% or greater and grafts that had undergone a procurement biopsy (Figure KI 97 and Figure KI 98).

3 Pediatric Kidney Transplant

3.1 Waiting List

In 2022, there were 1,099 pediatric candidates added to the kidney transplant waiting list (Figure KI 102). The number of prevalent pediatric candidates (listed before age 18 years) has increased by 31.7%, from 2,124 in 2011 to 2,797 in 2022 (Figure KI 103). By age, candidates aged 12-17 years accounted for the largest proportion of those waiting, at 36.7%, compared with those aged 18 years or older (ie, turned 18 while waiting) at 31.1%, 6-11 years at 17.8%, 1-5 years at 14.3%, and younger than 1 year at 0.07% (Figure KI 104). In terms of race and ethnicity, White candidates accounted for the largest group (42.7%) on the kidney transplant waiting list followed by Hispanic (27.9%), Black (19.6%), Asian (6.1%), Multiracial (2.8%), and Native American candidates (0.9%) (Figure KI 105). Over the past decade, candidate age, candidate sex, and distance of candidates from their transplant center have remained largely unchanged (Table KI 11). The proportion of Black candidates decreased by 32.0% since 2012 (Table KI 11). The proportion of candidates with congenital anomalies of the kidney and urinary tract as primary cause of disease continued to increase, from 27.8% in 2012 to 35.4% in 2022, and the proportions with glomerulonephritis and focal segmental glomerulosclerosis decreased (Table KI 12). Most pediatric candidates (68.4%) waiting on December 31, 2022, had a cPRA level of less than 1%, and there was a decline in the proportion of sensitized candidates with cPRA of 80% or greater (Table KI 12). The proportion of pediatric candidates waiting for retransplant (listed for retransplant before age 18) decreased over the past decade, from 31.2% in 2012 to 16.8% in 2022 (Table KI 13).

The distribution of waiting time among pediatric candidates on the waiting list has remained similar over the past decade, with almost 50% of pediatric candidates waiting for less than 1 year (Figure KI 108). In 2022, of the 1,018 candidates removed from the waiting list, 591 (58.1%) received a deceased donor kidney, 230 (22.6%) received a living donor kidney, 24 (2.4%) died, 13 (1.3%) were considered too sick to undergo transplant, and 9 (0.9%) were removed from the list because their condition improved (Table KI 14 and Table KI 15). Among patients newly listed in 2017-2019, within 3 years, 51.6% underwent DDKT, 24.6% underwent LDKT, 16.2% were still waiting, 6.6% were removed from the list for other reasons, and 1.1% died (Figure KI 110). Concerningly, the rate of DDKT among pediatric waitlisted candidates has decreased by 23.7%, from 44.9 transplants per 100 patient-years in 2011 to 34.3 transplants per 100 patient-years in 2022 (Figure KI 111). In 2022, transplant rates were highest for candidates aged 12-17 years (47.2 transplants per 100 patient-years), followed by candidates aged 6-11 years, 1-5 years, younger than 1 year, and 18 years or older (41.5, 36.5, 17.9, and 12.4 transplants per 100 patient-years, respectively) (Figure KI 112). By race and ethnicity, the highest transplant rates were among Hispanic (37.8 transplants by 100 patient-years) and Black candidates (36.4 transplants by 100 patient-years) followed by White (32.5 transplants by 100 patient-years) and Asian candidates (28.2 transplants by 100 patient-years) (Figure KI 113). Transplant rates typically vary by cPRA; the highest rates in 2022 were among candidates with cPRA levels of 20%-<80% (39.9 transplants per 100 patient-years) and less than 1% (36.4 transplants by 100 patient-years). The priority for highly sensitized (cPRA levels of 98%-100%) candidates continued to result in higher transplant rates than pre-KAS, at 13.8 transplants per 100 patient-years in 2022, which has remained steady since 2015 (Figure KI 114). Pretransplant mortality was 1.5 deaths per 100 patient-years in 2022 among pediatric candidates, which is unchanged from 1.4 deaths per 100 patient-years in 2011 (Figure KI 115).

3.2 Transplant

The total number of pediatric kidney transplants performed in 2022 decreased to its lowest point in the past decade, at 705; of these, 502 (71.2%) were DDKTs and 203 (28.8%) were LDKTs (Figure KI 119). The 203 LDKTs represent a decrease of 33% since 2011, when 303 were performed. Children aged 12-17 years made up the largest group of pediatric LDKT recipients (44.8%) (Figure KI 121).

In 2022, 34 programs were performing only pediatric kidney transplants (here, meaning age 0-17 years and a small number up to age 21 years), compared with 137 performing only adult transplants (18 years or older), 56 performing mixed transplants (in both adults and children of any age), and 8 performing transplants in the functionally adult category (performing 80% or more transplants in adults and the remainder in adolescents aged 15-17 years); these values represent an increase of 13.3%, an increase of 16.1%, a decrease of 13.8%, and a decrease of 61.9% since 2011, respectively (Figure KI 122).

Looking at transplant center volume, 18.4% of transplants in candidates younger than 18 years were performed at programs with a volume of five or fewer pediatric transplants in 2022 (Figure KI 123). Most pediatric recipients who underwent transplant in 2022 were aged 12-17 years: 59.6% of pediatric DDKT recipients and 44.8% of pediatric LDKT recipients (Table KI 16). The racial and ethnic distribution was notably different for pediatric DDKT and LDKT recipients. For LDKT recipients, 63.5% were White, followed by 16.7%, Hispanic; 11.8%, Black; 4.9%, Asian; 2.5%, Multiracial; and 0.5%, Native American (Table KI 16). In contrast, 39.6% of DDKT recipients were White, followed by 30.9%, Hispanic; 21.3%, Black; 5.2%, Asian; 2.8%, Multiracial; and 0.2%, Native American (Table KI 16). Private insurance was more common among LDKT recipients (51.7%) and Medicare/Medicaid among DDKT recipients (62.9%) (Table KI 16). Most pediatric DDKT recipients (97.8%) underwent transplant with a kidney from a donor with a KDPI of less than 35% (Table KI 18). Most pediatric DDKT recipients (82.2%) had four or more HLA mismatches compared with only 30.6% of LDKT recipients (Figure KI 126). Multiorgan transplant remained uncommon; only 2.6% of pediatric candidates received multiorgan transplant in 2022, with the most common being kidney-liver transplant (Table KI 18).

The combination of a donor who was positive for cytomegalovirus and a pediatric recipient who was negative occurred in 36.9% of DDKTs (Table KI 19) and in 29.0% of LDKTs (Table KI 20). The combination of a donor who was positive for EBV and a pediatric recipient who was negative occurred in 37.3% of DDKTs (Table KI 19) and in 56.6% of LDKTs (Table KI 20).

3.3 Immunosuppressive Medication Use

Almost all (93.9%) pediatric kidney transplant recipients reported some induction use in 2022 (Figure KI 124). The most common maintenance immunosuppression regimen at hospital discharge was tacrolimus, MMF, and steroids in 54.3% of recipients, followed by tacrolimus and MMF in 36.7% (Figure KI 125).

3.4 Outcomes

The rate of delayed graft function in pediatric recipients was 5.8% in 2022 and has been stable over the past decade (Figure KI 127). Short-term renal function, measured by eGFR, has remained stable over the past decade. Proportions of pediatric LDKT and DDKT recipients from 2021 with eGFR of 60 mL/min/1.73 m2 or higher at 12 months posttransplant were 69.8% and 69.2%, respectively (Figure KI 128 and Figure KI 129). Graft failure after DDKT in pediatric recipients was 2.2% at 6 months and 2.7% at 1 year for transplants in 2021, 7.1% at 3 years for transplants in 2019, 12.3% at 5 years for transplants in 2017, and 31.4% at 10 years for transplants in 2012 (Figure KI 130). Corresponding graft failure after LDKT was 1.3% at 6 months and 2.1% at 1 year for transplants in 2021, 5.0% at 3 years for transplants in 2019, 6.0% at 5 years for transplants in 2017, and 20.6% at 10 years for transplants in 2012 (Figure KI 131). For the cohort of recipients who underwent transplant in 2015-2017, the 1-, 3-, and 5-year graft survival were 97.5%, 93.0%, and 86.3% for DDKT recipients and 98.5%, 96.4%, and 93.7% for LDKT recipients, respectively (Figure KI 132). Looking at graft survival by recipient age, the 1-year graft survival ranged from 95.8% (age 1-5 years) to 97.5% (age 6-11 years), to 98.1% (age 12-17 years), to 100% (younger than 1 year) for DDKT recipients from 2015-2017 (Figure KI 133). The 5-year graft survival ranged from 83.7% (age 12-17 years) to 88.7% (age 1-5 years), to 90.7% (age 6-11 years), to 100% (younger than 1 year) for DDKT recipients from 2015-2017 (Figure KI 133). In the 2021 cohort, the overall incidence of acute rejection within the first year ranged from 7.6% among patients aged 1-5 years to 10.9% among patients aged 6-11 years and 13.0% among patients aged 12-17 years (Figure KI 134). Incidence of posttransplant lymphoproliferative disorder among EBV-negative recipients in 2011-2017 was 3.4% at 5 years posttransplant, compared with 0.9% among EBV-positive recipients (Figure KI 135). Overall, 5-year patient survival among pediatric DDKT recipients in 2015-2017 was very high, at 97.1% (Figure KI 137), with little variability by age: 95.8% (age 1-5 years), 97.2% (age 6-11 years), and 97.5% (age 12-17 years) (Figure KI 138).

References

1.
Axelrod DA, Schnitzler MA, Xiao H, Irish W, Tuttle-Newhall E, Chang SH, Kasiske BL, Alhamad T, Lentine KL. An Economic Assessment of Contemporary Kidney Transplant Practice. Am J Transplant. 2019;18(5):1168-1176. doi:10.1111/ajt.14702
2.
Executive Office of the President. Executive Order 13879 of July 10, 2019: Advancing American Kidney Health. Published online 2019. Accessed September 20, 2023. https://www.federalregister.gov/documents/2019/07/15/2019-15159/advancing-american-kidney-health
3.
Abara WE, Collier MG, Moorman A, Bixler D, Jones J, Annambhotla P, Bowman J, Levi ME, Brooks JT, Basavaraju SV. Characteristics of Deceased Solid Organ Donors and Screening Results for Hepatitis B, C, and Human Immunodeficiency Viruses — United States, 2010–2017. MMWR Morb Mortal Wkly Rep. 2019;68:61-66. doi:10.15585/mmwr.mm6803a2
4.
Husain SA, Lentine KL. Policy Strategies to Reduce Financial Risks for Living Donors. Kidney360. 2023;4(7):987-989. doi:10.34067/KID.0000000000000157
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Lentine KL, Naik AS, Schnitzler MA, Randall H, Wellen JR, Kasiske BL, Marklin G, Brockmeier D, Cooper M, Xiao H, Zhang Z, Gaston RS, Rothweiler R, Axelrod DA. Variation in Use of Procurement Biopsies and Its Implications for Discard of Deceased Donor Kidneys Recovered for Transplantation. Am J Transplant. 2019;19(8):2241-2251. doi:10.1111/ajt.15325
6.
Notice of OPTN Policy Change: Establish Minimum Kidney Donor Criteria to Require Biopsy. Published online 2022. Accessed October 30, 2023. https://optn.transplant.hrsa.gov/media/v2zfd4xp/policy-notice_est-min-kid-donor-crit-for-bpsy_kid.pdf
7.
Lentine KL, Fleetwood VA, Caliskan Y, Randall H, Wellen JR, Lichtenberger M, Dedert C, Rothweiler R, Marklin G, Brockmeier D, Schnitzler MA, Husain SA, Mohan S, Kasiske BL, Cooper M, Mannon RB, Axelrod DA. Deceased Donor Procurement Biopsy Practices, Interpretation, and Histology-Based Decision-Making: A Survey of US Kidney Transplant Centers. Kidney Int Rep. 2022;7(6):1268-1277. doi:10.1016/j.ekir.2022.03.021

List of Figures

List of Tables




**New adult candidates added to the kidney transplant waiting list.** A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Active and inactive patients are included. Candidates listed at more than one center are counted once per listing. Includes kidney and kidney-pancreas listings.

Figure KI 1: New adult candidates added to the kidney transplant waiting list. A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Active and inactive patients are included. Candidates listed at more than one center are counted once per listing. Includes kidney and kidney-pancreas listings.




**All adult candidates on the kidney transplant waiting list.** Adult candidates on the list at any time during the year. Candidates listed at more than one center are counted once per listing. Includes kidney and kidney-pancreas candidates.

Figure KI 2: All adult candidates on the kidney transplant waiting list. Adult candidates on the list at any time during the year. Candidates listed at more than one center are counted once per listing. Includes kidney and kidney-pancreas candidates.




**Distribution of adults waiting for kidney transplant by age.** Candidates waiting for transplant at any time in the given year. Candidates listed at more than one center are counted once per listing. Active and inactive candidates are included. Age is determined at the earliest of transplant, death, removal, or December 31 of the year.

Figure KI 3: Distribution of adults waiting for kidney transplant by age. Candidates waiting for transplant at any time in the given year. Candidates listed at more than one center are counted once per listing. Active and inactive candidates are included. Age is determined at the earliest of transplant, death, removal, or December 31 of the year.




**Distribution of adults waiting for kidney transplant by sex.** Candidates waiting for transplant at any time in the given year. Candidates listed at more than one center are counted once per listing. Active and inactive patients are included.

Figure KI 4: Distribution of adults waiting for kidney transplant by sex. Candidates waiting for transplant at any time in the given year. Candidates listed at more than one center are counted once per listing. Active and inactive patients are included.




**Distribution of adults waiting for kidney transplant by race and ethnicity.** Candidates waiting for transplant at any time in the given year. Candidates listed at more than one center are counted once per listing. Active and inactive patients are included.

Figure KI 5: Distribution of adults waiting for kidney transplant by race and ethnicity. Candidates waiting for transplant at any time in the given year. Candidates listed at more than one center are counted once per listing. Active and inactive patients are included.