Home hemodialysis and mortality risk in Australian and New Zealand populations

Background: There is a resurgence of interest in home hemodialysis (HD), especially frequent or extended forms involving unconventionally frequent (>3 times/wk) and/or long (>6 hours) treatments. This resurgence is driven by cost containment and experience suggesting lower mortality risk compared with facility HD and peritoneal dialysis (PD).

Study design: We performed an observational cohort study using the Australia and New Zealand Dialysis and Transplant Registry, using marginal structural modeling to adjust for time-varying medical comorbidity as both a source of selection bias and an intermediary variable on the causal pathway to death.

Setting & participants: All adult patients starting renal replacement therapy in Australia and New Zealand since March 31, 1996, followed up to December 31, 2007.

Predictor: The main predictor was dialysis modality (conventional facility HD, conventional home HD, frequent/extended facility HD, frequent/extended home HD, and PD). We adjusted for the confounding effects of patient demographics and comorbid conditions.

Outcome: Patient mortality.

Results: We analyzed 26,016 patients with 856,007 patient-months of follow-up. Relative to conventional facility HD, adjusted mortality HRs were 0.51 (95% CI, 0.44-0.59) for conventional home HD, 1.16 (95% CI, 0.94-1.44) for frequent/extended facility HD, 0.53 (95% CI, 0.41-0.68) for frequent/extended home HD, and 1.10 (95% CI, 1.06-1.16) for PD. The apparent benefit of home HD on mortality risk was less for patients who were nonwhite, non-Asian, and older.

Limitations: Potential for residual confounding from the limited collection of comorbid conditions (no collection of cognitive or motor impairment, depression, left ventricular volume or structure, or blood pressure/fluid volume status) and lack of socioeconomic, medication, and biochemical data in analyses.

Conclusions: Our study supports a survival advantage of home HD without a difference between conventional and frequent/extended modalities. Suitably designed clinical trials of frequent/extended HD are needed to determine the presence and extent of mortality benefit with this modality.