Race, Age, and Kidney Transplant Waitlisting Among Patients Receiving Incident Dialysis in the United States

Abstract

Rationale & objective: Patients with kidney failure from racial and ethnic minority groups and older patients have reduced access to the transplant waitlist relative to White and younger patients. Although racial disparities in the waitlisting group have declined after the 2014 kidney allocation system change, whether there is intersectionality of race and age in waitlisting access is unknown.

Study design: Retrospective cohort study.

Setting & participants: 439,455 non-Hispanic White and non-Hispanic Black US adults initiating dialysis between 2015 and 2019 were identified from the United States Renal Data System, and followed through 2020.

Exposures: Patient race and ethnicity (non-Hispanic White and non-Hispanic Black) and age group (18-29, 30-49, 50-64, and 65-80 years).

Outcomes: Placement on the United Network for Organ Sharing deceased donor waitlist.

Analytical approach: Age- and race-stratified waitlisting rates were compared. Multivariable Cox proportional hazards models, censored for death, examined the association between race and waitlisting, and included interaction term for race and age.

Results: Over a median follow-up period of 1 year, the proportion of non-Hispanic White and non-Hispanic Black patients waitlisted was 20.7% and 20.5%, respectively. In multivariable models, non-Hispanic Black patients were 14% less likely to be waitlisted (aHR, 0.86, 95% CI, 0.77-0.95). Relative differences between non-Hispanic Black and non-Hispanic White patients were different by age group. Non-Hispanic Black patients were 27%, 12%, and 20% less likely to be waitlisted than non-Hispanic White patients for ages 18-29 years (aHR, 0.73; 95% CI, 0.61-0.86), 50-64 (aHR, 0.88; 95% CI, 0.80-0.98), and 65-80 years (aHR, 0.80; 95% CI, 0.71-0.90), respectively, but differences were attenuated among patients aged 30-49 years (aHR, 0.89; 95% CI, 0.77-1.02).

Limitations: Race and ethnicity data is physician reported, residual confounding, and analysis is limited to non-Hispanic White and non-Hispanic Black patients.

Conclusions: Racial disparities in waitlisting exist between non-Hispanic Black and non-Hispanic White individuals and are most pronounced among younger patients with kidney failure. Results suggest that interventions to address inequalities in waitlisting may need to be targeted to younger patients with kidney failure.

Plain-language summary: Research has shown that patients from racial and ethnic minority groups and older patients have reduced access to transplant waitlisting relative to White and younger patients; nevertheless, how age impacts racial disparities in waitlisting is unknown. We compared waitlisting between non-Hispanic Black and non-Hispanic White patients with incident kidney failure, within age strata, using registry data for 439,455 US adults starting dialysis (18-80 years) during 2015-2019. Overall, non-Hispanic Black patients were less likely to be waitlisted and relative differences between the two racial groups differed by age. After adjusting for patient-level factors, the largest disparity in waitlisting was observed among adults aged 18-29 years. These results suggest that interventions should target younger adults to reduce disparities in access to kidney transplant waitlisting.