[Assessment of body composition and prognosis in chronic heart failure. Beyond the "obesity paradox"].

Objective: It is unknown the influence of body composition in the inverse relationship of mortality with overweight and obesity in heart failure patients.

Methods: 234 patients with chronic heart failure were evaluated. Body mass index, tricipital skinfold thickness, brachial muscle circumference and body fat percentage determined by bioelectrical impedance analysis were measured. The influence of previous anthropometric variables on total mortality was analyzed.

Results: Mean follow-up was 21±10.7 months. We observed an inverse relationship of total mortality with body mass index (hazard ratio=0.91, 95% confidence interval, 0.87-0.96; P<.001), with body fat estimated by the tricipital skinfold thickness (hazard ratio=0.95, 95% confidence interval, 0.92-0.99; P=.013) and the fat percentage obtained by bioelectrical impedance analysis (hazard ratio=0.96; 95% confidence interval, 0.93-0.99; P=.007) and with muscle mass estimated by the brachial muscle circumference (hazard ratio=0.87; 95% confidence interval,0.81-0.94; P=.001). Only brachial muscle circumference maintained its prognostic significance in multivariate analysis that included different anthropometric measurements (hazard ratio=0.88, 95% confidence interval 0.77-0.99; P=.035). Finally we found a positive linear correlation between the values of body mass index with tricipital skinfold thickness, fat percentage and brachial muscle circumference.

Conclusions: The muscle mass of patients with heart failure, estimated by the brachial muscle circumference, is associated inversely with overall mortality. The correlation between values of brachial muscle circumference with the body mass index would explain the "obesity paradox" observed.