Objective: To discuss potential reasons for reported differences in the results of several recent studies comparing mortality risk among continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis patients, and to assess the role of statistical methods and study design.
Data sources: Recent published reports comparing mortality risk among patients treated with CAPD and hemodialysis.
Conclusions: Differences in study design, study populations, sample size, data collection, and availability of data likely account in part for the differences in available study results. The Cox model is a valuable tool, particularly for observational studies. Observed outcome differences for CAPD and hemodialysis patients may be due to either the dialytic modality itself or other factors such as differences in patient selection, practice patterns, dialysis dose, patient compliance, etc. Relative mortality rates for hemodialysis and CAPD patients may vary by country, as these factors may differ internationally. A randomized clinical trial is necessary to best determine the effect of the modality itself.