LOWER PROBABILITY OF PATIENT SURVIVAL WITH CONTINUOUS PERITONEAL-DIALYSIS IN THE UNITED-STATES COMPARED WITH CANADA

In a prospective cohort study of 680 incident continuous peritoneal di alysis (PD) patients in North America, dialysis in the United States c ompared with Canada was associated with a relative risk (RR) of death of 1.93 (95% confidence interval [CI], 1.14 to 3.28). The 2-yr surviva l probability was 79.7% in Canada and 63.2% in the United States. This difference was not explained by race, age, gender, functional status, insulin-dependent diabetes mellitus, history of cardiovascular diseas e (CVD), nutritional status, or adequacy of dialysis. Other potential explanatory variables were further evaluated. These included severity of CVD, residual renal function, race, differential transfer to hemodi alysis or transplantation, patient compliance, modality selection bias , and incidence of endstage renal disease requiring dialysis. Cardiova scular morbidity and peritonitis probabilities were compared. The CVD severity index was not different between countries; the RR risk associ ated with dialysis in the United States remained high at 1.87 (95% CI, 1.09 to 3.19). Residual renal function at initiation of dialysis was not different between countries. The 2-yr survival for Caucasians was 77% in Canada and 55% in the United States. There was no difference in the probability of transfer to hemodialysis or transplantation. The R R of a nonfatal cardiovascular event in the United States compared wit h Canada was 1.80 (95% CI, 1.21 to 2.67). There was no difference in t ime to first peritonitis. The observed to predicted creatinine ratio, as an estimate of compliance, was 1.13 in Canada and 1.00 in the Unite d States. The prevalence of PD in the study centers was 48% in Canada and 22% in the United States. The incidence of new dialysis patients i n 1992 was 100/million population in Canada compared with 211/million in the United States. The survival difference is not explained by age, gender, insulin-dependent diabetes mellitus, nutritional status, or a dequacy of dialysis, Neither is it explained by race, severity of CVD, transfer to hemodialysis, transplantation, or an estimate of complian ce. The lower proportion of patients receiving PD in the United States may represent a selection bias of uncertain direction, The higher acc eptance rate for dialysis in the United States may explain, in part, t he greater cardiovascular morbidity and the decreased survival observe d.