Comparison of direct body composition assessment methods in patients with chronic heart failure

We examined the validity of leg-to-leg bioelectrical impedance analysis (BIA) and near-infrared interactance (NIR) to assess body composition in chronic heart failure (CHF) patients.

A total of 140 patients with CHF were enrolled in this cross-sectional study between June 2008 and July 2009. Dual energy x-ray absorptiometry (DEXA) served as the reference standard. A priori, desired precision levels were set at ± 3.5% body fat and ± 3.5 kg lean body mass. Mean age was 63, 74% were male, and 90% were Caucasian. BIA- and NIR-ascertained percent body fat and lean body mass were highly correlated to DEXA. Mean differences and limits of agreement for NIR were -0.3% ± 5.1% for percent body fat and 2.9 kg ± 4.3 kg for lean body mass. Mean difference and limits of agreement for BIA percent body fat was 0.8% ± 5.8%. BIA lean body mass showed poor agreement with DEXA because of variable limits of agreement across the range of measurement (Pitman's test P < .0001).

In patients with CHF, both NIR and BIA accurately measure body fat. However, both methods were imprecise. NIR overestimated lean body mass and BIA was not useful to assess this parameter. Further study is required, including examination of the utility of these field methods in serially assessing body composition.