Association of overtime urine volume and ultrafiltration changes with patient survival in continuous ambulatory peritoneal dialysis patients.

Background: Associations between patient survival and baseline urine volume (UV), ultrafiltration (UF) volume, and combined UV and UF were evaluated in Iranian continuous ambulatory peritoneal dialysis (CAPD) patients. Methods: From 1995 to 2006, data on 1472 CAPD patients from 26 centers were collected. Demographic, clinical, and laboratory characteristics were analyzed using STATA software. Baseline UV was considered as an indicator of residual renal function and patients with an annual decrease of more than 250 cc/day were placed in decreasing UV group. The role of a new variable, net positive fluid removal, which defines as the combination of baseline UV and UF, was also evaluated. Results: Patients with higher baseline UV were significantly more married and educated and candidate for CAPD based on positive selection criteria. In dichotomous categorization, mean of serum creatinine was lower and albumin was higher in patients with UV ≥ 1000 cc/day compared with UV < 250 cc/day. A significant correlati...