Changes in body composition parameters in patients on haemodialysis and peritoneal dialysis.

Introduction: Proper hydration is one of the major aims in haemodialysis (HD) and peritoneal dialysis (PD). Bioimpedance spectroscopy appears to be a promising method for the evaluation and follow up of the hydration status in dialysis patients (P).
Objectives: We compared body composition between stable patients on HD and PD after six months.
Patients and Method: An observational study with 62 P on HD and 19 P on PD was performed. Clinical, biochemical and bioimpedance parameters were analysed.
Results: In the comparative study, PD P were younger (50 ± 10 vs 57 ± 14 years, P=.031). The Charlson Comorbidity Index (4.8 ± 3 vs 7.5 ± 3, P<.001), time on dialysis (16.9 ± 18.01 vs 51.88 ± 68.79 months, P=.020) and C-Reactive Protein [3 (3-9.3) vs 5.25 (1-76.4)] were lower. Total protein levels (7.46 ± 0.44 vs 7.04 ± 0.55 g/dl, P=.005) and transferrin levels (205 ± 41 vs 185 ± 29 mg/dl, P=.024) were higher. BIS: Intracellular water (19.67 ± 3.61 vs 16.51 ± 3.36 litres, P=.010), lean tissue mass (LTM) (37.20 ± 8.65 vs 32.57 ± 8.72 kg, P=.029), total cellular mass (TCM) (20.53 ± 5.65 vs 17.56 ± 5.91 kg, P=.033), and bioelectrical impedance phase angle (Phi 50) (5.81 ± 0.86 vs 4.74 ± 0.98, P=.000) were higher than in HD P. Overhydration: 22% in HD y 10% in PD, in conditions referred to in methods. Six months later, PD P increased in weight (73.75 ± 12.27 vs 75.22 ± 11.87 kg, P=.027), total fat (FAT) (26.88 ± 10 vs 30.02 ± 10 kg, P=.011) and relative fat (Rel FAT) (35.75 ± 9.87 vs 39.34 ± 9.12, P=.010); and decreased in ICW (18.56 ± 3.45 vs 17.65 ± 3.69 l, P=.009), LTM (36.95 ± 8.88 vs 34 ± 9.70 kg, P=.008) and relative LTM (Rel LTM) (50.85 ± 12.33 vs 45.40 ± 11.95%, P=.012). In the multivariate analysis, weight variation (∆) was related to ∆ FAT (P < .001). We found a correlation between fat increase and lean tissue mass decrease. Six months later, in HD P, we observed a reduction in ECW (15.11 ± 2.45 vs 14.00 ± 2.45, P.001), without changes in other parameters.
Conclusions: Bioelectrical impedance analysis facilitates the assessment of changes in body composition so as to correct dry weight and to introduce changes in treatment schedule..