Association between attributed cause of end-stage renal disease and risk of death in Brazilian patients receiving renal replacement therapy

Background. Studies conducted in several countries have indicated that the survival of patients undergoing renal replacement therapy (RRT) depends on the attributed cause of end-stage renal disease ( ESRD). Objectives. This study was conducted to evaluate the association between attributed cause of ESRD and mortality risk in RRT patients in Brazil. Methods. We analyzed 88,881 patients from the Brazilian Ministry of Health Registry who were undergoing RRT between April 1997 and July 2000. Cox proportional hazards models were used to estimate the relative risk (RR) of death in patients with ESRD secondary to diabetes mellitus (DM), polycystic kidney disease (PKD), and primary glomerulopathies (GN) compared with a reference group comprised of patients with ESRD caused by hypertensive nephropathy. Patient's age, gender, and length of time ( years) in RRT before inclusion in the registry ( vintage) were included in the adjusted Cox model. Results. Compared with the reference group, the mortality risk was 27% lower in patients with PKD (RR = 0.73, 95% CI: 0.65-0.83, p < 0.0001); 29% lower in patients with GN (RR = 0.71, 95% CI: 0.68-0.74, p < 0.0001); and 100% greater in DM patients (RR = 2.00, 95% CI: 1.92-2.10, p < 0.0001). These relative risks remained statistically significant after adjustment for age, gender, and length of time in RRT before inclusion in the registry. Conclusions. Our data indicate that compared with the patients with hypertensive nephrosclerosis as attributed cause of ESRD, patients undergoing RRT in Brazil with idiopathic glomerulopathy and polycystic kidney disease have a lower risk of mortality, and patients with diabetes mellitus have a greater risk of mortality.