Correlation between diaphragmatic function and skeletal muscle mass in chronic obstructive pulmonary disease

Background Skeletal muscle dysfunction occurs in patients with chronic obstructive pulmonary disease and influences both respiratory and nonrespiratory muscles. This is a very important comorbidity leading to a poor prognosis, including increased mortality and hospitalization. It is the result of a complex combination of functional, metabolic, and anatomical changes that result in suboptimal muscle performance. Objective To identify the correlation between change in skeletal muscle mass (SMM) and diaphragmatic thickness and excursion in chronic obstructive pulmonary disease (COPD) patients. Patients and methods Cross sectional study, comprising of 44 stable COPD patients underwent transthoracic ultrasound assessment of diaphragmatic thickness and excursion, SMM estimation using body sense smart scale machine, and ultrasound estimation of biceps and triceps thickness and then the results were correlated. Results Diaphragmatic thickness and excursion had significant positive correlations with corresponding SMM, biceps thickness and triceps thickness as well as significant negative correlation with smoking pack/years and number of exacerbations in the last year. Conclusions Low SMM is a relevant comorbidity in COPD patients and associated with affected diaphragmatic function as regard thickness and excursion. High Smoking pack/years and high number of exacerbations are significant independent factors that decrease diaphragmatic thickness and excursion, and increased the likelihood of having low SMM. Change in SMM and diaphragmatic function negatively affect the health status represented in the number of exacerbations in the last year.