Survival comparison between hemodialysis and peritoneal dialysis based on matched doses of delivered therapy

Several studies have recently confirmed that hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) survival is highly associated with delivered therapy Kt/V_urea. A direct comparison of equivalently dosed CAPD and HD has not previously been performed. A total of 968 incident HD patients at the Regional Kidney Disease Program from 1987 to June 1995 were studied, and these results were compared with those of the Canadian-United States prospective trial (CANUSA) consisting of 680 incident CAPD patients from September 1990 to December 31, 1992, with follow-up through December 31, 1993. All patients had quantitation of urea nitrogen for a total delivered dialysis session. On HD, in vivo, 2-pool, pre- and post-blood urea nitrogen kinetic modeling was performed with residual renal function determined every 6 mo. Patients were characterized by age, gender, race, renal diagnosis, and comorbid conditions. A Cox proportional hazards model was used to evaluate the effect of the individual comorbid conditions and the effect of dialysis therapy in the time-dependent method. The mean total Kt/V, both residual renal function and dialytic therapy in the HD patients, was 1.59. The CANUSA-delivered weekly Kt/V was 2.38 at the beginning of the baseline period and 1.99 after 24 mo of follow-up. When the peak concentration hypothesis was used, a Kt/V of 1.59 on HD was equivalent to a weekly CAPD dose of 2.1 to 2.2. A 1-unit increase in Kt/V was associated with 7% lower risk of death on HD and with a similar 8% lower risk of death while on CAPD. Patients with diabetes aged 46 to 60 yr had virtually identical 2-yr survival estimates on HD (83 to 90%), compared with CAPD (83 to 89%), with Kt/V ranges from 0.84 to 1.70 in HD and from 1.6 to 2.2 weekly Kt/V on peritoneal dialysis. Comparisons between HD and CAPD in older patients with diabetes yielded comparable results. Patient survival is highly influenced by delivered dialysis in both HD and peritoneal dialysis. Carefully matching of the therapies with delivered Kt/V demonstrates little differences in the survival outcome of HD and peritoneal dialysis patients, in contrast to some previous reports.