Purpose: Pulmonary rehabilitation programs are effective in patients with severe chronic obstructive pulmonary disease (COPD) in the short term, but their long-term effects are not known. We investigated the short- and long-term effects of a 6-month outpatient rehabilitation program in patients with severe COPD.
Subjects and methods: One hundred patients were randomly assigned to receive either an exercise training program that included cycling, walking, and strength training (n = 50) or usual medical care (n = 50). Thirty-four patients in the training group were evaluated after 6 months (end of training), and 26 were evaluated after 18 months of follow-up. In the control group, 28 patients were evaluated at 6 months and 23 after 18 months. We measured pulmonary function, 6-minute walking distance, maximal exercise capacity, peripheral and respiratory muscle strength, and quality of life (on a 20 to 140-point scale), and estimated the cost-effectiveness of the program.
Results: At 6 months, the training group showed improvement in 6-minute walking distance [mean difference (training - control) of 52 m; 95% confidence interval (CI), 15 to 89 m], maximal work load (12 W; 95% CI, 6 to 19 W), maximal oxygen uptake (0.26 liters/min; 95% CI, 0.07 to 0.45 liters/min), quadriceps force (18 Nm; 95% CI, 7 to 29 Nm), inspiratory muscle force (11 cm H(2)O; 95% CI, 3 to 20 cm H(2)O), and quality of life (14 points; 95% CI, 6 to 21 points; all P <0.05). At 18 months all these differences persisted (P <0.05), except for inspiratory muscle strength. For 6-minute walking distance and quality of life, the differences between the training group and controls at 18 months exceeded the minimal clinically-important difference.
Conclusion: Among patients who completed the 6-month program, outpatient training resulted in significant and clinically relevant changes in 6-minute walking distance, maximal exercise performance, peripheral and respiratory muscle strength, and quality of life. Most of these effects persisted 18 months after starting the program.