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 [HRcs], 0.67; 95% CI, 0.64-0.71) and 40-59 years (HRcs, 0.67; 95% CI, 0.66-0.68), 19% lower at ages 60-79 years (HRcs, 0.81; 95% CI, 0.80-0.82), and 6% lower at 80 years or older (HRcs, 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 [HRsd], 0.90; 95% CI, 0.85-0.94) and from 33% to 19% among those aged 40-59 years (HRsd, 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.