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

BACKGROUND

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 (DEmax) measured using ultrasonography is associated with longitudinal changes in the cross-sectional area of the ESM (ESMCSA) in patients with COPD.

METHODS

This retrospective cohort study included 60 patients with stable COPD who underwent pulmonary function testing, computed tomography (CT), and diaphragmatic excursion measurements. The ESMCSA 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 DEmax, 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.

RESULTS

DEmax and MIP were significantly correlated with baseline ESMCSA and %ΔESM. DEmax 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 DEmax had greater annual ESMCSA loss, indicating progressive muscle atrophy.

CONCLUSIONS

Lower diaphragmatic excursion was independently associated with accelerated loss of ESMCSA in patients with COPD. DEmax 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.