Survival analysis: comparing peritoneal dialysis and hemodialysis in Taiwan.

OBJECTIVES: Comparisons of survival in patients on peritoneal dialysis (PD) and on hemodialysis (HD) have been conducted in many Western countries, but publications on this subject in Asian populations are scarce. The present study estimated the survival and the relative mortality hazard for HD and PD patients in Taiwan.

METHODS: Incident end-stage renal disease patients reported to the Taiwan Renal Registry during 1995 - 2002 were included in the study. Patients had to be 20 years of age or older and had to have survived for the first 90 days on dialysis. A total of 45,820 incident HD and 2,809 incident PD patients formed the study population. Patients on PD were treated mainly with traditional glucose-based solutions. Using an intent-to-treat analysis, the Cox proportional hazards (CPH) model was applied to identify the factors that predict survival by treatment modality. Subgroup analyses were conducted by stratifying patients according to sex, comorbidity, age, and diabetes status. Kaplan-Meier estimates were used to explore the survival of HD and PD patients. Adjustments were implemented using the CPH model.

RESULTS: The overall 1-year, 2-year, 3-year, 5-year and 10-year survival rates for PD patients were 89.8%, 77.6%, 67.6%, 55.5%, and 35% respectively. The equivalent survival rates for HD patients were 87.5%, 76.6%, 68.1%, 54.3%, and 33.8%. The differences were not statistically significant (p = 0.125). The CPH analysis stratified by diabetes status and age revealed that PD patients 55 years of age or younger and nondiabetic had a lower mortality ratio (MR) of 0.94. But the MR increased to 1.31 for nondiabetic patients older than 55. The MR for PD versus HD further increased to 1.72 for diabetic patients 55 years of age or younger, and to 1.99 for diabetic patients older than 55.

CONCLUSIONS: After adjusting for both demographic and clinical case-mix differences, PD and HD patients were observed to have similar long-term survival. Subgroup analyses revealed that, among diabetic patients and patients older than 55, those on HD experienced better survival than did those on PD.