Body composition and health-related quality of life in patients with obstructive airways disease.

This study evaluated the effects of body weight and lean mass abnormalities on health-related quality of life (HRQL) in obstructive airways disease. Body weight, lean mass (using dual-energy X-ray absorptiometry), and HRQL (using the St George's Respiratory Questionnaire (SGRQ)) were measured in 50 patients. Low lean mass was defined as a lean mass index (lean mass/height2) below the fifth percentile of a control population. Dyspnoea was measured by the baseline dyspnoea index. The mean (SD) age was 69+/-9 yrs; the forced expiratory volume in one second (FEV1) was 39+/-19% of predicted. Patients had 2.4+/-4.1 kg less lean mass than predicted. Increased dyspnoea was the most influential predictor of poor HRQL. Compared to normal-weight patients, those who were underweight had significantly greater impairment in activity, impact, and total SGRQ scores, while those who were overweight had greater impairment in impact and total SGRQ scores. Low lean mass was associated with greater impairment in symptoms, activity and impact subscores and the total SGRQ score. When dyspnoea was added to the model as a covariate, neither weight nor lean mass remained significantly related to HRQL. Thus, although body weight and lean mass abnormalities influence health-related quality of life, their effects appear to be mediated through increased levels of dyspnoea.