Improved assessment of body cell mass by segmental bioimpedance analysis in malnourished subjects and acromegaly

Background: Estimation of body cell mass (BCM) has been regarded valuable for the assessement of malnutrition. Aim: To investigate the value of segmental bioelectrical impedance analysis (BIA) for BCM estimation in malnourished subjects and acromegaly. Methods: Nineteen controls and 63 patients with either reduced (liver cirrhosis without and with ascites, Cushingʹs disease) or increased BCM (acromegaly) were included. Whole-body and segmental BIA (separately measuring arm, trunk, leg) at 50kHz was compared with BCM measured by total-body potassium. Multiple regression analysis was used to develop specific equations for BCM in each subgroup. Results: Compared to whole-body BIA equations, the inclusion of arm resistance improved the specific equation in cirrhotic patients without ascites and in Cushingʹs disease resulting in excellent prediction of BCM (R2=0.93 and 0.92, respectively; bothP<0.001). In acromegaly, inclusion of resistance and reactance of the trunk best described BCM (R2=0.94, P<0.001). In controls and in cirrhotic patients with ascites, segmental impedance parameters did not improve BCM prediction (best values obtained by whole-body measurements: R2=0.88 and 0.60; P<0.001 and <0.003, respectively). Conclusion: Segmental BIA improves the assessment of BCM in malnourished patients and acromegaly, but not in patients with severe fluid overload.