Diaphragmatic excursion is associated with longitudinal changes in erector spinae muscle in patients with chronic...

Skeletal muscle dysfunction, a common extrapulmonary manifestation in patients with chronic obstructive pulmonary disease (COPD), contributes to decreased physical activity and poor prognosis. Among skeletal muscles, erector spinae muscle (ESM) is crucial in posture and respiratory support. However, the association between the diaphragmatic function and ESM remains unclear. This study aimed to determine whether diaphragmatic excursion (DE_max) measured using ultrasonography is associated with longitudinal changes in the cross-sectional area of the ESM (ESM_CSA) in patients with COPD.

This retrospective cohort study included 60 patients with stable COPD who underwent pulmonary function testing, computed tomography (CT), and diaphragmatic excursion measurements. The ESM_CSA was calculated from chest CT at two points, and its annual change rate (%ΔESM) was analysed. Correlations were examined between %ΔESM and clinical parameters, including DE_max, maximal inspiratory pressure (MIP), body mass index, age, FEV₁% predicted, and 6-min walk distance. Multiple regression analysis was used to determine independent predictors of %ΔESM.

DE_max and MIP were significantly correlated with baseline ESM_CSA and %ΔESM. DE_max was the only independent predictor of %ΔESM after adjusting for covariates (β = 0.47, p = 0.0249), while MIP lost significance. Patients with a lower DE_max had greater annual ESM_CSA loss, indicating progressive muscle atrophy.

Lower diaphragmatic excursion was independently associated with accelerated loss of ESM_CSA in patients with COPD. DE_max is a potentially simple, noninvasive predictor of skeletal muscle atrophy and can be used to identify patients at risk of physical decline, enabling early intervention strategies, such as rehabilitation.