Bioimpedance and echocardiography used interchangeably in volume comparison of dialysis patients

Euvolemia is a major issue in chronic kidney disease. The present study compares cardiac condition and volume status in peritoneal dialysis (PD) and hemodialysis (HD) patients and points out importance of volume control.

From a single-center center, 81 PD and 89 HD patients were enrolled. Echocardiography and body composition analysis using bioimpedance spectroscopy (BIS) technique were performed. Overhydration (OH) and extracellular water (ECW) in liters and OH/ECW % were used as volume indices.

Patients were younger (47.6±14. 5 and 53.1±11.8 years, p< 0.05), daily urine volume higher (1068±926 vs 290±444 ml, p <0.001) and dialysis vintage was shorter (30.1±18.6 vs 53.6±35.4 months, p<0.001), systolic blood pressure was lower (127.5±15.4 vs 140.3±18.9 mmHg, p<0.001) in PD than HD group respectively. Volume indices were (OH, OH/ECW %, ECW/height, ECW to Intracellular Water ratios (E/I) (p<0.05)) significantly higher in HD patients compared to PD patients. Over all 66 of 170 patients (39%) had OH/ECW % <5 and OH/ECW % ratio was positively correlated with Left atrium index (R(2):0.105, p<0.05). Interventricular septum diameter and Left ventricular mass index (1.41±0.24 and 159.6±48.2 vs. 1.27±0.17 cm and 115.8±37 g/m(2), p<0.001) were increased in HD than in PD group. After multivariate adjustment OH/ECW increased with: HD and diabetic patients. LVH increased with: HD group, OH/ECW (%) and SBP significantly.

Overhydration was more common among HD. Excess fluid may lead adverse effect in organ functions especially cardiac condition. This indicates that the current clinical and technical tools to achieve euvolemia are insufficient and that an additional tool, such as BIS, could be useful in the diagnosis of overhydration.