Bioelectrical Impedance Analysis in the Assessment of Hydration Status in Peritoneal Dialysis Patients

Objective: Assessment of fluid status in chronic peritoneal dialysis (PD) patients is complex. Clinical evaluation based solely on body weight, blood pressure, volume of ultrafiltration (UF) and peripheral edema is insufficient. A non-invasive test, bioelectrical impedance analysis (BIA) might be of potential benefit. Aim: To test whether BIA correlates with other ancillary markers of extracellular fluid volume, namely B-type natriuretic peptide (BNP), residual renal function (RRF) and UF, and whether BIA provides complementary information in categorizing PD patients vis-a-vis hydration status. Methods: A cross-sectional study of 61 out-patients on chronic PD. Single-frequency BIA measurements of resistance/height were divided into tertiles (lowest: <253 Omega/m; middle: >= 253 Omega/m and <316 Omega/m; highest: >= 316 Omega/m). Results: Compared to patients in the highest tertile of BIA (least fluid), patients in the lowest tertile (most fluid) had highest BNP, RRF and UF (93.5 vs. 55.0 pg/ml, p = 0.029; 850 vs. 300 ml/day, p = 0.05; and 1.75 vs. 1.21 l/day, p = 0.023, respectively). Conclusions: BIA tertiles categorized PD patients who differed in BNP, RRF and UF in a stepwise pattern, suggesting BIA may better inform hydration status, and serve as an additional clinical tool in management of chronic PD patients. Copyright (c) 2012 S. Karger AG, Basel