Socio-economic status and incidence of renal replacement therapy: a registry study of Australian patients.

Background: Socio-economic disadvantage has been linked to higher incidence of end-stage kidney disease in developed countries. Associations between socio-economic status (SES) and incidence of renal replacement therapy (RRT) have not been explored for different kidney diseases, genders or age groups in a country with universal access to healthcare.

Methods: We investigated the incidence of non-indigenous patients commencing RRT in Australia in 2000-09, using the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. Patient postcodes were grouped into deciles using a standard SES index. We analysed incidence by five groups of kidney diseases, age groups, gender and geographic remoteness.

Results: Incidence of RRT decreased with increasing area advantage. Differences were most evident for the most disadvantaged areas [markedly increased burden; incident rate ratio (IRR) 1.27; 95% confidence interval (CI) 1.18-1.38] and most advantaged decile (decreased burden, IRR 0.76; 95% CI 0.72-0.81), compared with decile 5. Patients with diabetic nephropathy showed the greatest disparities: residents of the most disadvantaged decile were 2.38 (95% CI 2.09-2.71) times more at risk than the most advantaged decile. Congenital and genetic kidney diseases showed lesser gradients-the most disadvantaged decile was 1.28 times (95% CI 0.98-1.68) more at risk. SES was not associated with incidence for patients older than 69 years.

Discussion: These SES gradients existed, despite all Australians having access to healthcare. Diseases associated with lifestyle show the greatest gradients with SES.