Inspiratory muscle training compared with other rehabilitation interventions in chronic obstructive pulmonary disease: a systematic review update.

Purpose: To determine the effect of inspiratory muscle training (IMT) (alone or combined with exercise and/or pulmonary rehabilitation) and compare with other rehabilitation interventions among adults with chronic obstructive pulmonary disease (COPD).
Methods: We conducted a systematic review, using Cochrane Collaboration protocol. We included randomized controlled trials, published in English, comparing IMT or combined IMT and exercise/pulmonary rehabilitation with other rehabilitation interventions among adults with COPD. Abstracts were reviewed independently by 2 investigators to determine study eligibility up to December 2005. Data were abstracted and methodological quality of included studies was assessed.
Results: A total of 156 additional articles were retrieved. Two new studies met the inclusion criteria and were included with 16 studies in the original review. Results highlight updated subgroup analyses comparing (1) IMT versus exercise and (2) combined IMT and exercise versus exercise alone. Fourteen meta-analyses were performed for outcomes of inspiratory muscle strength, exercise tolerance, and quality of life. Results showed significant improvements in maximum inspiratory pressure and maximum exercise tidal volume favoring combined IMT and exercise compared with exercise alone.
Conclusions: Performing a combination of IMT plus exercise may lead to significant improvements in inspiratory muscle strength and one outcome of exercise tolerance for individuals with COPD.