Supplementary Material for: Impact of Age, Race and Ethnicity on Dialysis Patient Survival and Kidney Transplantation Disparities

Background: Prior studies show that African-American and Hispanic dialysis patients have lower mortality risk than whites. Recent age-stratified analyses suggest this survival advantage may be limited to younger age groups, but did not concurrently compare Hispanic, African-American, and white patients, nor account for differences in nutritional and inflammatory status as potential confounders. Minorities experience inequities in kidney transplantation access, but it is unknown whether these racial/ethnic disparities differ across age groups. Methods: The associations between race/ethnicity with all-cause mortality and kidney transplantation were separately examined among 130,909 adult dialysis patients from a large national dialysis organization (entry period 2001-2006, follow-up through 2009) within 7 age categories using Cox proportional hazard models adjusted for case-mix and malnutrition and inflammatory surrogates. Results: African-Americans had similar mortality versus whites in younger age groups (18-40 years), but decreased mortality in older age groups (>40 years). In contrast, Hispanics had lower mortality versus whites across all ages. In sensitivity analyses using competing risk regression to account for differential kidney transplantation rates across racial/ethnic groups, the African-American survival advantage was limited to >60-years age categories. African-Americans and Hispanics were less likely to undergo kidney transplantation from all donor types versus whites across all ages, and these disparities were even more pronounced for living donor kidney transplantation (LDKT). Conclusions: Hispanic dialysis patients have greater survival versus whites across all ages; in African-Americans, this survival advantage is limited to patients >40 years of age. Minorities are less likely to undergo kidney transplantation, particularly LDKT, across all ages.