Inspiratory muscle strength relative to disease severity in adults with stable cystic fibrosis

BackgroundDue to heterogeneity in pulmonary disease, current literature may misrepresent inspiratory muscle involvement in cystic fibrosis (CF). This study investigated inspiratory muscle strength (IMS) relative to disease severity in adults with CF.MethodsMaximal inspiratory pressure (MIP) was assessed in 58 adults with stable CF grouped by disease severity (20 mild, 20 moderate, 18 severe) and compared to 20 controls. Relationships between MIP, lung function, dyspnea and anthropometrics were evaluated using multivariable linear models.ResultsMIP in cmH2O and %-predicted was decreased in advanced CF lung disease as compared to mild disease and healthy controls (p < 0.05). Disease severity accounted for 24% of the variance in IMS after controlling for confounding variables (p < 0.001).ConclusionsIMS is decreased in some adults with stable CF with moderate and severe pulmonary disease, and is related to dyspnea. Future studies should determine if decreased IMS contributes inefficient breathing patterns, respiratory pump dysfunction, and/or exercise intolerance in advanced CF.