Erector spinae muscle thickness predicts mortality in patients with pulmonary diseases

Loss of skeletal muscle mass contributes to poor respiratory disease outcomes. We previously developed an easy method for assessing physical activity by measuring erector spinae muscle thickness (ESM_T) via routine chest computed tomography (CT). Since chest CT is commonly performed in hospitalized patients with pulmonary diseases, ESM_T can be readily evaluated. In this study, we aimed to investigate the association between ESM_T and 1-year mortality in such patients.

We prospectively enrolled patients hospitalized for pulmonary diseases between February 2023 and January 2024. Among the 636 patients included, 162 died within one year (mortality group), and 474 survived (survival group). ESM_T was compared between the groups, and its correlations with clinical parameters were examined. Subgroup analyses were conducted for patients with major pulmonary conditions to assess the broader clinical utility of ESM_T.

Lower ESM_T was significantly associated with higher 1-year mortality risk according to the Cox proportional hazard model (hazard ratio: 0.96, 95 % confidence interval: 0.92-0.99, p = 0.035). An ESM_T ≤20.55 mm predicted increased mortality risk. Subgroup analyses confirmed the associations between low ESM_T and mortality across pneumonia, interstitial lung disease, chronic obstructive pulmonary disease, and nontuberculous mycobacteria and/or bronchiectasis. ESM_T also correlated significantly with age, males, body weight, body mass index, activities of daily living (ADL), pre-admission living place, use of home oxygen therapy, and SARC-F scores.

ESM_T is a useful and easy marker for predicting 1-year mortality and impaired ADL status in patients with pulmonary diseases.