Trends in relative mortality between hispanic and non-hispanic whites initiating dialysis: A retrospective study of the us renal data system

Background: Hispanic patients undergoing long-term dialysis experience better survival compared with non-Hispanic whites. It is unknown whether this association differs by age, has changed over time, or is due to differential access to kidney transplantation. Study Design: National retrospective cohort study. Setting & Participants: Using the US Renal Data System, we identified 615,618 white patients 18 years or older who initiated dialysis therapy between January 1, 1995, and December 31, 2007. Predictors: Hispanic ethnicity (vs non-Hispanic whites), year of end-stage renal disease incidence, age (as potential effect modifier). Outcomes: All-cause and cause-specific mortality. Results: We found that Hispanics initiating dialysis therapy experienced lower mortality, but age modified this association (P < 0.001). Compared with non-Hispanic whites, mortality in Hispanics was 33% lower at ages 18-39 years (adjusted cause-specific HR [HR_cs], 0.67; 95% CI, 0.64-0.71) and 40-59 years (HR_cs, 0.67; 95% CI, 0.66-0.68), 19% lower at ages 60-79 years (HR_cs, 0.81; 95% CI, 0.80-0.82), and 6% lower at 80 years or older (HR_cs, 0.94; 95% CI, 0.91-0.97). Accounting for the differential rates of kidney transplantation, the associations were attenuated markedly in the younger age strata; the survival benefit for Hispanics was reduced from 33% to 10% at ages 18-39 years (adjusted subdistribution-specific HR [HR_sd], 0.90; 95% CI, 0.85-0.94) and from 33% to 19% among those aged 40-59 years (HR_sd, 0.81; 95% CI, 0.80-0.83). Limitations: Inability to analyze Hispanic subgroups that may experience heterogeneous mortality outcomes. Conclusions: Overall, Hispanics experienced lower mortality, but differential access to kidney transplantation was responsible for much of the apparent survival benefit noted in younger Hispanics.