Dialysis outcomes of elderly Indigenous and non-Indigenous Australians

Abstract

Aim: Whilst increasing numbers of elderly people in Australia are commencing dialysis, few Indigenous patients are aged ≥65 years and their outcomes are unknown. We compared the long-term survival, mortality hazards and causes of death between elderly Indigenous and elderly non-Indigenous dialysis patients. Methods: This was a retrospective cohort study of adults aged ≥65 years who commenced dialysis in Australia from 2001–2011, identified from the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. Indigenous (n= 263) and non-Indigenous (n= 10713) patients were followed until death, loss to follow-up, recovery of renal function or 31 December 2011. Mortality was compared using a multivariate Cox proportional-hazards model with age, gender, body mass index, smoking, primary renal disease, comorbidities, late referral and initial treatment modality as predictive variables. Results: Median follow-up was 26.9 months (interquartile range 11.3–48.8 months). Overall 166 Indigenous and 6265 non-Indigenous patients died during the 11-year follow-up period. Mortality rates per 100 patient-years were 23.9 for Indigenous patients and 21.2 for non-Indigenous patients. The overall 1-, 3- and 5-year survival rates were 81%, 49% and 27% for Indigenous patients and 82%, 55% and 35% for non-Indigenous patients respectively. Indigenous patients had a 20% increased risk of mortality compared with non-Indigenous patients (adjusted hazard ratio 1.20, 95% confidence interval, 1.02, 1.41;P= 0.02). ‘Social deaths’ (predominantly dialysis withdrawal) and cardiac deaths were the main causes of death for both groups. Conclusion: Among elderly dialysis patients in Australia, Indigenous status remains an important factor in predicting survival.