Survival of Indigenous Australians receiving renal replacement therapy: closing the gap?

To compare mortality rates for Indigenous and non-Indigenous Australians commencing renal replacement therapy (RRT) over time and by categories of remoteness of place of residence.

An observational cohort study of Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) data on Indigenous and non-Indigenous Australians registered with ANZDATA who commenced RRT from 1 January 1995 to 31 December 2009 and were followed until 31 December 2011.

Five-year all-cause mortality for Indigenous and non-Indigenous patients in three cohorts (1995-1999, 2000-2004 and 2005-2009) and five remoteness (of place of residence) categories.

Indigenous patients were younger, more likely to have diabetes, be referred late and be from a more remote area than non-Indigenous patients. Age and comorbid conditions increased with successive cohorts for both groups. Unadjusted analysis (using the log-rank test) showed an increased risk of death for Indigenous patients in the 1995-1999 (P = 0.02) and 2000-2004 (P = 0.03) cohorts, but not for the 2005-2009 cohort (P = 0.7). However, a Cox proportional hazards model adjusted for covariates (age, sex, late referral and comorbid conditions [diabetes, coronary artery disease, peripheral vascular disease, cerebrovascular disease, lung disease], and body mass index < 18.5 kg/m(2) and > 30 kg/m(2)) showed the following Indigenous:non-Indigenous hazard ratios (with 95% CIs) for major capital cities: 1995-1999, 1.47 (1.21-1.79); 2000-2004, 1.35 (1.12-1.63); and 2005-2009, 1.37 (1.14-1.66).

Although unadjusted analysis suggests that the survival gap between Indigenous and non-Indigenous patients receiving RRT has closed, there remains a significant disparity in survival after adjusting for the variables considered in our study.