Differences in survival on peritoneal dialysis between oriental Asians and Caucasians: one center's experience

Abstract

Background: Recently it has been suggested that the survival of dialysis patients may differ among different races. Both registry data and data from Asian countries indicates that Asians on peritoneal dialysis may survive longer than their Caucasian counterparts. In the present study, we performed a detailed analysis of survival differences between oriental Asians and Caucasians on peritoneal dialysis in our multiethnic, multicultural program.

Methods: Retrospectively we analyzed the survival data for patients who started peritoneal dialysis after January 1, 1996 and before December 31, 1999, in our hospital. They were followed for at least for two years. Excluded from the present analysis were those who survived for less than three months on peritoneal dialysis. The patient demographic characteristics, comorbidities, and residual renal function at the start of dialysis were collected. Indices for adequacy of dialysis were collected 1-3 months after the initiation of dialysis. Actuarial survival rates were determined by the Kaplan-Meier method. The Cox proportional hazards model was used to classify risk factors for a high mortality.

Results: There were 87 Caucasians and 29 Oriental Asian peritoneal dialysis patients. No differences were found in age, gender, primary renal disease, and residual renal function between the two groups. The Caucasians had significantly higher body surface area and urea volume and higher incidence of cardiovascular diseases. Even with slightly higher dialysis dose, the peritoneal creatinine clearance was significantly lower among the Caucasians than among Asians. There was no difference in the peritoneal D/P value between the two groups. However, compared to the Caucasians, the 24hr peritoneal fluid removal and total fluid removal volumes were significantly lower in the Asian patients. The one, two, three and four year survival rates were 95.8%, 91%, 86% and 80% for Asians and 91.3%, 78.1%, 64.7% and 54.1% for Caucasians. Significant predictors for a higher mortality were the presence of cardiovascular disease (42% increase in risk), Caucasians (39% increase in risk) and older age (37% increase in risk for age older than 65).

Conclusions: Our study confirms that oriental Asians on peritoneal dialysis patients survive much longer than their Caucasian counterparts; this was partly due to the fact that Asian patients have less cardiovascular disease when they began peritoneal dialysis. Due to their smaller body size, the Asians tended to have a higher peritoneal small solute clearances despite their smaller dialysis doses, indicating that, to achieve the same solute clearance targets, Asians need a smaller dialysis dose compared to Caucasians.