Impact of Bronchodilator Responsiveness on Quality of Life and Exercise Capacity in Patients With COPD

Abstract

Bronchial variability in COPD patients may be a phenotypic feature associated with clinical characteristics and differential treatment response. We analyzed whether symptoms, quality of life, and exercise capacity varied in COPD patients as a function of bronchodilator test results, and compared responses to an exercise program. A positive bronchodilator test result was defined as FVC and/or FEV1 improvement of > 12% plus > 200 mL after 400 μg of salbutamol. We studied 198 COPD subjects: 94 with positive reversibility, and 104 with negative reversibility. Training sessions were carried out on 3 non-consecutive days each week, for 12 weeks, and consisted of a combination of resistance and strength training. Subjects were evaluated on 2 consecutive days at baseline, and at the end of the 12-week training program. Those with positive reversibility had shorter time to exhaustion in the endurance test (19.1 ± 12.6 min vs 24.5 ± 14.5 min, P = .03), shorter shuttle walk test distance (380.6 ± 158.2 m vs 438.5 ± 149.1 m, P = .02), and lower Chronic Respiratory Disease Questionnaire scores (18.7 ± 4.6 vs 19.8 ± 4.3, P = .01). There were no significant differences in peak exercise, peripheral muscle strength, dyspnea, or improvement after exercise training. Compared to COPD subjects with negative reversibility, those with positive reversibility walked for shorter distances, and had shorter endurance times and worse quality of life, but the improvements after exercise training were similar.