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.