Inspiratory Muscle Training plus Pulmonary Rehabilitation versus Rehabilitation alone in COPD A Systematic Review of Randomized Controlled Trials

Background Pulmonary rehabilitation (PR) is an established intervention for COPD, but the added value of inspiratory muscle training (IMT) within PR remains uncertain. This systematic review examined whether IMT plus PR provides benefits beyond PR alone in adults with moderate to severe COPD. Methods PubMed, ScienceDirect, Cochrane Library, and Web of Science were searched from inception to January 2023. Randomized controlled trials (RCTs) comparing IMT+PR with PR alone in adults with moderate to severe COPD were included. Primary outcomes were inspiratory muscle strength (PImax), dyspnea, health related quality of life (HRQoL), exercise capacity [six minute walk test (6MWT)], and pulmonary function tests (PFTs). Risk of bias was assessed using the Cochrane RoB 2.0 tool. Results Nine RCTs (n=295) met the inclusion criteria. IMT+PR improved PImax in 6/9 studies, with gains of 5.2 to 22.9 cmH 2 O. Dyspnea improved in 6/8 studies, often exceeding the minimal clinically important difference (MCID). HRQoL improved in all studies assessing this outcome (6/6), although superiority of IMT+PR over PR or control conditions was not consistently demonstrated. Exercise capacity findings were mixed, with significant within-group 6MWT gains in 4 of 7 studies but inconsistent between-group differences. PFTs (FEV 1 , FVC) were generally unchanged, while limited data from single-center trials suggest reductions in dynamic hyperinflation and small increases in inspiratory capacity. Conclusion Adding IMT to PR meaningfully improves PImax and HRQoL in moderate to severe COPD, with frequent but less consistent benefits for dyspnea and 6MWT performance and minimal effect on spirometry. IMT may be most appropriate for patients with inspiratory muscle weakness (PImax