Aim: Low socio-economic status (SES) is associated with increased incidence of end-stage kidney disease and in the USA, poorer dialysis survival. All Australians have access to a universal healthcare system.
Methods: The study included all non-indigenous adult Australians registered with the Australia and New Zealand Dialysis and Transplant Registry who commenced dialysis between 2003 and 2013. SES at dialysis start was classified into quartiles of advantaged through to disadvantaged using Australian Bureau of Statistics socio-economic indexes for areas. The primary outcome was survival assessed using a competing risk regression model with renal transplantation as a competing risk. There was a significant interaction between age and SES, and hence, age-stratified survival analyses were performed.
Results: A total 20 810 commenced dialysis during the study period. Mortality for the most advantaged quartile was 102.4/1000 person-years (95% confidence interval (CI) 98.0-106.9) compared with 110.7/1000 person-years (95% CI 105.8-115.7) in the disadvantaged quartile. In adjusted analysis, dialysis survival, compared with quartile 1 (advantaged), was inferior in quartile 3 (sub-hazard ratio 1.10, 95% CI 1.03-1.17) and the disadvantaged quartile (sub-hazard ratio 1.09, 85% CI 1.02-1.16) and was significantly modified by age. This disparity in survival outcome between the different SES quartiles was only observed in younger patients but was attenuated in the older ones following an age-stratified analysis.
Conclusions: In Australia, low SES has an adverse effect on dialysis patient survival despite universal healthcare. This effect is mainly among younger patients where SES may have a greater proportional impact than co-morbidities.
Keywords: ANZDATA; dialysis; income; kidney; mortality; socio-economic status.
© 2017 Asian Pacific Society of Nephrology.