Effect of eliminating priority points for HLA-B matching on racial disparities in kidney transplant rates

Background: African Americans have lower rates of obtaining a deceased donor kidney transplant (DDKT) compared with their white counterparts. One proposed mechanism is differential HLA distributions between African Americans and whites. In May 2003, the United Network for Organ Sharing/Organ Procurement and Transplantation Network changed kidney allocation policy to eliminate priority based on HLA-B matching in an effort to address this disparity. The objective of this study was to quantify the effect of the change in policy regarding priority points for HLA-B matching.

Study design: Observational cohort study.

Setting & participants: A cohort of 178,902 patients registered for a DDKT between January 2000 and August 2009.

Factors: African Americans versus whites before and after the policy change. Cox models were adjusted for age, sex, diabetes, dialysis type, insurance status, education, panel-reactive antibody level, and blood type.

Outcomes: Adjusted relative rates (aRRs) of deceased donor kidney transplant for African Americans compared with whites.

Measurements: Time from initial active wait listing to DDKT, censored for living donor kidney transplant and death.

Results: Before the policy change, African Americans had 37% lower rates of DDKT (aRR, 0.63; 95% CI, 0.60-0.65; P < 0.001). After the policy change, African Americans had 23% lower rates of DDKT (aRR, 0.77; 95% CI, 0.76-0.79; P < 0.001). There was a 23% reduction in the disparity between African Americans and whites after the policy change (interaction aRR, 1.23; 95% CI, 1.18-1.29; P < 0.001).

Limitations: As an observational study, findings could have been affected by residual confounding or other changes in practice patterns.

Conclusions: Racial disparity in rates of DDKT was decreased by the HLA-B policy change, but parity was not achieved. There are unaddressed factors in kidney allocation that lead to continued disparity on the kidney transplant waiting list.