A 30-year observational cohort study of children with childhood-onset kidney failure found that Black patients are disadvantaged in all aspects of kidney transplantation into adulthood compared with White patients, according to investigators.
Among other disparities, Black patients have a significantly higher overall mortality rate and lower graft survival rate compared with White patients. Black patients also are less likely to undergo preemptive transplantation.
Investigators speculate that socioeconomic factors might contribute to the disparities.
“Our analysis demonstrated that Black patients faced more economic challenges as evidenced by a greater likelihood of living in areas of low median household income, having Medicaid as primary payer, or having no health insurance, all of which could present barriers to transplant access and limit the chance of preemptive transplantation,” they wrote.
Using 1980-2017 US Renal Data System (USRDS) data, Susan R. Mendley, MD, and colleagues from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health in Bethesda, Maryland, studied 28,337 children– 24% Black and 76% White — diagnosed with ESKD before age 18 years.
Compared with White patients, Black patients had a significantly lower unadjusted 30-year overall survival rate (39% vs 57%) and significantly lower rate of preemptive transplantation (23.6% vs 13.4%), the investigators reported in the Journal of the American Society of Nephrology.
Compared with White patients, Black patients had a significant 45% higher risk for all-cause mortality, a 31% lower rate of first transplant, and a 39% lower rate of second transplant, Dr Mendley’s team reported. A significantly lower proportion of Black patients had a living donor for a first (26.0% vs 49.2%) or second kidney transplant (15.4% vs 35.1%).
After their first transplant, Black patients received 11% fewer total lifetime transplants compared with White patients, according to the investigators. A significantly higher proportion of Black than White patients never received a transplant (23.6% vs 13.4%).
Among transplanted patients, graft survival was shorter in Black than White patients (median 6.1 vs 10.3 years). Graft survival was 20% and 24% lower after the first and second transplant, respectively, for the Black population.
The risk for mortality was 38% and 23% higher after the first and second transplant, respectively, for Black patients, the investigators reported. These trends largely persisted across defined eras from 1980 through 2017 with no meaningful improvement in outcomes over time despite medical and technical advancements. The investigators could not assess how 2014 changes in the Kidney Allocation System may have affected outcomes.
Transplantation was associated with a 72% decreased risk for death over a lifetime for patients with childhood-onset ESKD, Dr Mendley and colleagues reported. Yet time with a functioning allograft was significantly shorter for Black than White patients who began renal replacement therapy in childhood: 57% vs 83% of follow-up time, respectively.
In a simulation, investigators found that equalizing transplant number, graft survival, and time with a functioning transplant would reduce Black excess mortality from 45% to 34%.
“This indicates that 35% of the excess mortality between Black and White patients would be eliminated if the transplant experience was the same in each racial group, but 65% of the survival differential would remain from other mediators independent of transplantation,” Dr Mendley’s team wrote.
Transplant waiting time, graft survival, and access to subsequent transplants may all contribute to the disparity in time with a functioning graft, the investigators noted. They suggested that social determinants of health and the consequences of structural racism likely play important roles. A greater proportion of the Black than White population had a low median household income of less than $34,000 (56.2% vs 11.1%) and Medicaid as primary insurance (48.3% vs 32.9%). The study lacked more granular information on socioeconomic status, comorbidities, and body mass index, which is a limitation.
Increasing kidney transplant rates and improving allograft survival for Black children and young adults has the potential to help close the survival gap, Dr Mendley’s team concluded.
“Defining transplant as a modifiable risk factor for death and measuring the consequences of racial disparities in access may generate policy changes to repair them.”
Becerra AZ, Chan KE, Eggers PW, et al. Transplantation mediates much of the racial disparity in survival from childhood-onset kidney failure. J Am Soc Nephrol. Published online March 3, 2022. doi:10.1681/ASN.2021071020