Adverse prognostic indicators in continuous ambulatory peritoneal dialysis patients without obvious vascular or...

Factors that predict the occurrence of vascular events and poor patient survival in continuous ambulatory peritoneal dialysis (CAPD) patients have not been clearly defined. Previous studies have focused on nonselective CAPD patients, in whom pre-existing comorbidity or poor health might complicate interpretation of the significance of individual factors. The present study was conducted with CAPD patients without severe vascular and nutritional comorbidity.

This single-center, prospective, observational study was conducted with 66 prevalent CAPD patients without co-existing severe vascular or nutritional problems. The patients were enrolled in January 1999. We monitored baseline demographic data and clinical and laboratory characteristics including average clinic blood pressure (BP), hemoglobin (Hb), serum albumin, intact parathyroid hormone (iPTH), serum cholesterol, triglycerides, dialysate-to-plasma (D/P) creatinine, dialysis adequacy [Kt/V and creatinine clearance (CCr)], and protein equivalent of nitrogen appearance. We followed the patients for 3 years. Outcome measures were actuarial patient survival, time to occurrence of cerebrovascular accident (CVA) and acute myocardial infarction (AMI), technique survival, and hospitalization rate.

Mean age of the patients was 56.7 +/- 10.3 years. Mean duration on CAPD at the time of enrollment was 36.4 +/- 21.7 months. Nineteen of the patients (28.8%) had diabetes. Most of the patients [n = 55 (83.3%)] were using three 2-L exchanges daily. Mean body weight was 56.3 +/- 12.2 kg. Mean total weekly Kt/V was 1.91 +/- 0.47, and mean total weekly CCr was 75.3 +/- 30.6 L/1.73 m(2). Actuarial patient survival was 96.9% at 1 year, 90.5% at 2 years, and 75.3% at 3 years. Overall technique survival was 96.9% at 1 year, 95.1% at 2 years, and 89.1% at 3 years. Multivariate analysis showed that age, diabetes mellitus (DM), and body size (weight or surface area) were independent predictors of patient survival. We estimated that a 1-kg increase in body weight was associated with a 6% increase in the relative risk of death (p = 0.015; 95% confidence interval: 1.013 to 1.126). Patients with a body weight of 60 kg or less showed a significantly better 3-year survival as compared with patients with body weight greater than 60 kg (88.1% vs 58.3%, p = 0.0042). No significant predictors were identified for technique failure or occurrence of a major vascular event. High BP and DM were independent predictors for hospitalization. Dialysis adequacy indices and serum albumin showed no significant effect on any outcome measure.

Our study showed that, in addition to age and DM, body size could also be a significant factor affecting survival of CAPD patients. However, the underlying causative mechanisms remain unclear and require further study.