title: Association of overtime urine volume and ultrafiltration changes with patient survival in continuous ambulatory peritoneal dialysis patients.
abstract: 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 correlation was found between baseline UV <250 cc/day and ≥1000 cc/day and patient survival. Patients with stable UV had better survival compared with patients with decreasing UV (p = 0.04). There was no correlation between UF and patient survival. Remarkable association with patient and technique survival and net positive fluid removal ≥2000 cc/day and <500 cc/day was observed. Multiple Cox regression analysis revealed significant correlation between net positive fluid removal ≥2000 cc/day and higher patient survival [p = 0.01, hazard ratio (HR) = 13.2], higher first albumin (albumin ≥ 3.5 mg/dL, p = 0.01, HR = 0.02), and lower negative selection (p = 0.0001, HR = 11.8).
  
  
  CONCLUSIONS
  Loss of UV over time and lower net positive fluid removal increase mortality of PD patients.
authors.affiliation: Division of Nephrology, Department of Medicine, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Monir Sadat
authors.initials: MS
authors.lastname: Hakemi
authors.forename: Iraj
authors.initials: I
authors.lastname: Najafi
authors.forename: Amir Ahmad
authors.initials: AA
authors.lastname: Nassiri
authors.forename: Sudabeh
authors.initials: S
authors.lastname: Alatab
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Saddadi
authors.forename: Tayabeh
authors.initials: T
authors.lastname: Soleymanian
authors.forename: Manouchehr
authors.initials: M
authors.lastname: Amini
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Ganji
authors.forename: Nader Nouri
authors.initials: NN
authors.lastname: Majelan
authors.forename: Mostafa
authors.initials: M
authors.lastname: Hosseini
mesh_terms: D005260:Female; D017583:Hemodiafiltration / Q000401:mortality*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000401:mortality*; D015996:Survival Rate; D013997:Time Factors; D014556:Urine