Background
Black kidney transplant recipients experience disproportionately high rates of graft loss. This disparity has persisted for 40 years and improvements may be impeded based on the current public reporting of overall graft loss by U.S. regulatory organizations for transplantation.
Methods
Longitudinal cohort study of kidney transplant recipients using a dataset created by linking Veterans Affairs and U.S. Renal Data System information, including 4,918 veterans transplanted between Jan 2001 and Dec 2007, with follow up through Dec 2010. Multivariable analysis was conducted using two-stage joint modeling of random and fixed effects of longitudinal data (linear mixed model) with time to event outcomes (Cox regression).
Results
3,306 Non-Hispanic Whites (67%) were compared to 1,612 Non-Hispanic Black (33%) recipients with 6.0±2.2 years of follow-up. In the unadjusted analysis, Black recipients were significantly more likely to have overall graft loss (HR 1.19, 95%CI 1.07–1.33), death censored graft loss (HR 1.67, 1.45–1.92) and lower mortality (HR 0.83, 0.72–0.96). In fully adjusted models, only death censored graft loss remained significant (HR 1.38, 1.12–1.71; overall graft loss [HR 1.08, 0.91–1.28]; mortality [HR 0.84, 0.67–1.06]). A composite definition of graft loss reduced the magnitude of disparities in Blacks by 22%.
Conclusions
Non-Hispanic Black kidney transplant recipients experience a substantial disparity in graft loss, but not mortality. This study of U.S. data provides evidence to suggest that researchers should focus on using death censored graft loss as the primary outcome of interest to facilitate a better understanding of racial disparities in kidney transplantation.