Comparison of long-term survival between hemodialysis and peritoneal dialysis.

We have reviewed the literature and our own center's results for patients on long-term continuous ambulatory peritoneal dialysis (CAPD) in comparison to results for patients on hemodialysis (HD). Contrary to recent American data showing one-year survivals to be worse on CAPD, the Canadian Registry and other studies show no significant difference in survivals on the two methods. Results are also conflicting for diabetics. Insufficient adjustments for age and case-mix variations are probably the most important causes for differences. For the general population, personal Cox-adjusted data show no difference between CAPD and HD up to ten-year follow-up, with very close curves for the adults and non-significant differences for the elderly. Old elderly (> 75 years) have better survival on CAPD in the first years of treatment. Dropout, which is higher on CAPD, decreases with age, and the patient retention on CAPD is worse than on HD for all patients, except the old elderly, for whom it is similar. These data were obtained in patients receiving a standard treatment, modified in order to give a more adequate dialysis dose only in recent years. The results of a prospective three-year study on the effect of nutritional [serum albumin and transferrin, normalized protein catabolic rate (PCRN), and subjective global assessment of malnutrition] and adequacy indices [Kt/V, creatinine clearance (Ccr), residual renal function] on patient survival on CAPD and HD are reported. Survival was not different for the two methods. Using the Cox analysis, nutritional indices did not affect survival whereas adequacy indices did. The effect of low serum albumin on survival was referable to the predialysis nutritional state. The similar survivals obtained on CAPD and HD, with Kt/V more or less than 1.0/treatment for HD and 1.7/week for CAPD, support the "peak concentration hypothesis" of Keshaviah et al. Survival in different groups of patients with different Kt/V and Ccr shows that the adequate dose on CAPD is Kt/V between 1.96 and 2.03 and Ccr > or = 70 L/week. A group of 26 patients who remained on CAPD treatment for more than eight years was also studied. Patient age and predialysis comorbidity were the most important factors affecting survival. Patients surviving longest had > 3 g/dL of serum albumin, > 0.8 g/kg/day of PCRN, a Kt/V > 1.6, and a weekly Ccr > 54L/week.