Temporal changes in mortality risk by dialysis modality in the Australian and New Zealand dialysis population

BACKGROUND: In most studies, home dialysis associates with greater survival than facility hemodialysis (HD). However, the relationship between mortality risk and modality can vary by era. We describe and compare changes in survival with facility HD, peritoneal dialysis, and home HD over a 15-year period using data from The Australia and New Zealand Dialysis and Transplant Registry (ANZDATA). STUDY DESIGN: An observational inception cohort study, using Cox proportional hazards and competing-risks regression. SETTING PARTICIPANTS: All adult patients initiating renal replacement therapy in Australia and New Zealand since March 31, 1998, followed up to December 31, 2012. PREDICTOR: Era at dialysis inception (1998-2002, 2003-2007, and 2008-2012). We adjusted for time-varying dialysis modality and comorbid conditions, demographics, initial state/country of treatment, late referral for nephrology care, primary kidney disease, and kidney function at dialysis inception. OUTCOMES: Patient mortality. RESULTS: Survival on dialysis therapy has improved despite increasing patient comorbid conditions. Compared to 1998 to 2002, there has been a 21 reduction in mortality for those on facility HD therapy, a 27 reduction for those on peritoneal dialysis therapy, and a 49 reduction for those on home HD therapy. LIMITATIONS: Potential for residual confounding from limited collection of comorbid conditions; analyses lack data for blood pressure, fluid volume status, socioeconomics, medication, and biochemical parameters. CONCLUSIONS: Our study indicates that outcomes on dialysis therapy are improving with time and that this improvement is most marked with home dialysis modalities, especially home HD. This might be the result of better dialysis care (eg, improving predialysis care and more appropriate selection of patients for home dialysis). Other contributing factors are possible, such as improvements in general care of patient comorbid conditions and improvements in dialysis technology, although further research is needed to clarify these issues.