Meta-analysis of the Effect of a Pulmonary Rehabilitation Program on Respiratory Muscle Strength in Patients with Chronic Obstructive Pulmonary Disease

Abstract

Purpose: Pulmonary rehabilitation (PR) programs are important in the treatment of patients with chronic obstructive pulmonary disease (COPD) but vary widely in type, duration, and efficacy. This meta-analysis investigated the effect of PR programs on respiratory muscle strength in patients with COPD.

Methods: PubMed, Embase, and CINAHL were searched. The primary outcome variables were maximal expiratory pressure (MEP) and maximal inspiratory pressure (MIP). The secondary outcome variables were the modified Borg score after the 6-min walking test, percent predicted forced expiratory volume in 1 second (FEV₁%pred), and percent FEV₁/forced volume capacity (FVC). Comprehensive Meta-Analysis, version 3.0, was used to analyze the data. The effect size was calculated using the standardized mean difference (SMD) and 95% confidence interval (CI).

Results: Twenty randomized controlled trials (with 992 participants) were included in the analysis. The PR programs had a significant effect on the MEP (SMD, 0.87; 95% CI, 0.42-1.32; p < .001), MIP (SMD, 0.53; 95% CI, 0.13-0.93; p = .009), and modified Borg score (SMD, -0.37; 95% CI, -0.52 to -0.22; p < .001) in patients with COPD. There was no effect on FEV₁%pred (SMD, 0.09; 95% CI, -0.12 to 0.30; p = .406) or FEV₁/FVC% (SMD, 0.04; 95% CI, -0.17 to 0.26; p = .702).

Conclusion: PR programs improve respiratory muscle strength in patients with COPD. Strategies for selecting a suitable PR program need to be developed, and future studies should evaluate the long-term effects of such programs on pulmonary function.

Keywords: meta-analysis; pulmonary disease, chronic obstructive; respiratory muscles.