Pulmonary rehabilitation improves exercise capacity and quality of life in underweight patients with chronic obstructive pulmonary disease

Background and objective: An estimated 20-40% of COPD patients are underweight. We sought to confirm the physiological and psychosocial benefits of pulmonary rehabilitation programmes (PRP) in underweight compared with non-underweight patients with COPD. Methods: Twenty-two underweight COPD patients with BMI <20 kg/m(2), and 22 non-underweight COPD patients, who were matched for FEV1 and age, were studied. All patients had moderate-to-very severe COPD. All patients participated in 12-week, hospital-based outpatient PRP consisting of two sessions per week. Baseline and post-PRP status were evaluated by spirometry, cardiopulmonary exercise testing, ventilatory muscle strength and the St. George's Respiratory Questionnaire (SGRQ). Results: At baseline, the age distribution and airflow obstruction were similar in underweight and non-underweight patients with COPD. Baseline exercise capacity, inspiratory muscle strength and SGRQ total and symptoms scores were significantly lower in the underweight patients (all P < 0.05). After the PRP, there was significant weight gain in the underweight COPD patients (mean increase 0.8 kg, P = 0.01). There were also significant improvements in peak oxygen uptake, peak workload and the SGRQ total, symptoms, activity and impact scores in both underweight and non-underweight patients with COPD (all P < 0.05). Conclusions: Underweight patients with COPD have impaired exercise capacity and health-related quality of life (HRQL). Exercise training with supplemental oxygen may result in significant weight gains and improvements in exercise capacity and HRQL. Exercise training is indicated for underweight patients with COPD.