Effect of Pulmonary Rehabilitation on Erector Spinae Muscles in Individuals With COPD

BACKGROUND: A recent paper reported that low muscle mass in the erector spinae muscles (ESM) was strongly associated with poor prognosis and declining muscle mass over time in subjects with COPD. However, effects of pulmonary rehabilitation (PR), if any, on ESM mass have not been reported. We hypothesized that PR reduces the annual decline in ESM mass.

METHODS: This was a retrospective cohort study. Thirty-nine subjects with COPD who received PR and underwent chest computed tomography before and after PR were evaluated (rehabilitation group). We also evaluated 39 age-matched subjects with COPD who did not receive PR (nonrehabilitation group). Data were collected from August 2010 until March 2020 in both groups. The ESM cross-sectional area (ESM_CSA) was measured using axial computed tomography images, and annual changes were calculated. The 6-min walk distance (6MWD) was measured before and after PR; the minimum clinically important difference was defined as 30 m.

RESULTS: ESM_CSA declined in the nonrehabilitation group over time (−116.0 ± 141.2 mm²/y) but increased in the PR group (51.0 ± 95.3 mm²/y; P < .001). The annual increase in ESM_CSA was significantly higher among subjects with an increase in 6MWD that exceeded the minimum clinically important difference compared with nonresponders in the rehabilitation group. The annual change in ESM_CSA was negatively correlated with comorbidity index, and triple therapy (long-acting β₂-agonist/long-acting muscarinic antagonist/inhaled corticosteroid) had a favorable effect on annual change in ESM_CSA. Multiple regression analysis revealed that only PR was an independent factor for annual change in ESM_CSA.

CONCLUSIONS: ESM mass was shown to decline yearly in subjects with COPD. The annual decline in muscle mass was reduced by PR.