Body Fat Mass as Predictors of Survival in Hemodialysis Patients and Its Association With Clinical Metabolic Profiles, Markers of Inflammation and Adipocytokines in Chronic Hemodialysis Patients: a Prospective Study.

Patient Selection

Clinically stable stage 5 chronic kidney disease patients (400 patients) attending the Tungs Taichung Metroharbour will be enrolled in this study. These patients will be given written information and are invited to participate in the study. Written informed consent will be obtained from each patient enrolled. Our hospital dialysis center undergoes multi-frequency bioelectrical impedance analysis( BIA) scanning on a bimonthly basis as part of their ongoing clinical care. Multi-frequency BIA is performed on patients attending the center as part of their routine dry weight assessment. Among these patients, eighty ambulatory adults attending for thrice-weekly outpatient hemodialysis treatments concomitantly had similar dual-energy X-ray absorptiometry (DEXA) scan and postdialysis multi-frequency BIA assessments for review. Patients with implantable defibrillators, those with cardiac pacemakers, and amputees are excluded from the study. This study will be conducted prospectively for 3 years.

Methods Body Composition Assessment Measurements with dual-energy X-ray absorptiometry (DEXA)

DEXA was performed with patients in the supine position. The radiation exposure is estimated to be one tenth of that for standard chest radiography. DEXA is scheduled postdialysis. Whole-body composition, including total and segmental lean, total body fat mass, and bone mineral content, will be calculated using the compatible software. For patients with multiple multifrequency BIA estimations, the study performed will be arranged temporally to the DEXA scan for more relevant comparison.

Measurement of Bioimpedance In all patients BIS will be carried out bimonthly using the Body Composition Monitor (Fresenius Medical Care Deutschland Gesellschaft mit beschrankter Haftung (GmbH), Germany), which takes measurements at 50 frequencies in a range of 5 to 1000 kilohertz(KHz). The measurement was performed approximately 30 minutes after the midweek hemodialysis session, with four conventional electrodes being placed in the patient, who was lying in the supine position: two in the hand and two in the foot contralateral to the vascular access. Regarding the quality of measurements, all exceeded 95%. The manufacturer of the Body Composition Monitor (Fresenius Medical Care) indicated that 30 minutes after the hemodialysis session, the balance between intra-and extracellular fluid was restored and no significant differences in relation to pre-dialysis values were observed. Parameters obtain directly through BIS that are used in this study are free fat mass, lean body mass, intracellular water (ICW) and extracellular water( ECW). Protein-energy wasting (PEW), represented by the intracellular water/dry body weight (ICW/BW) ratio, and overhydration, represented by the extracellular water/dry body weight(ECW/BW) ratio will be analysed.