The Ratio of Extracellular Fluid to Total Body Water and Technique Survival in Peritoneal Dialysis Patients

Abstract

Patients receiving peritoneal dialysis experience a high technique failure rate and are often overhydrated. We examined whether an increased extracellular fluid volume (VECF) as a proportion of the total body water (VTBW) predicted technique survival (TS) in a prevalent patient cohort. The VECF and VTBW were estimated by multiple-frequency bioelectric impedance in 59 prevalent peritoneal dialysis patients (median time on dialysis 14 months). Demographic, biochemical (albumin, C-reactive protein, and ferritin), and anthropometric data, forearm muscle strength, nutritional score by three-point Subjective Global Assessment, residual renal function, dialysate-to-plasma (D/P) creatinine ratio, total weekly Kt/V urea, total creatinine clearance, normalized protein equivalent of nitrogen appearance, and midarm muscle circumference were also assessed. Technique survival was determined at 3 years, and significant predictors of TS were sought. In patient groups defined by falling above or below the median value for each parameter, only residual renal function (p = 0.002), 24-hour ultrafiltrate volume (p = 0.02), and VECF/VTBW ratio (p = 0.05) were significant predictors of TS. Subjects with a higher than median VECF/VTBW ratio had a 3-year TS of 46%, compared to 78% in subjects with a lower than median value. In multivariate analysis, systolic blood pressure and VECF/VTBW ratio (both p < 0.05) were significant predictors of TS. C-reactive protein approached significance. Increased ratio of extracellular fluid volume to total body water is associated with decreased TS in peritoneal dialysis.