The Cross-Sectional Area of Erector Spinae Muscles Obtained from Chest CT Is an Independent Predictor of Death in COPD.

Background: Skeletal muscle loss usually predicts poor clinical outcomes in patients with chronic obstructive pulmonary disease (COPD). However, the prognostic value of erector spinae muscle (ESM) in COPD remains unclear.

Methods: The cross-sectional area of ESM (ESMCSA) was retrospectively measured on a single-slice axial image obtained from chest computed tomography of COPD patients. The clinical characteristics and 5-year all-cause mortality of these patients were recorded.

Results: The ESMCSA of COPD patients in the non-survivor group was significantly lower than that in the survivor group (P<0.001). Decreased ESMCSA was significantly correlated with pulmonary function decline (P<0.001). The threshold of ESMCSA to predict the 5-year all-cause mortality of COPD was 23.42cm², and Kaplan-Meier survival curves showed that the 5-year cumulative survival rate of COPD patients was significantly decreased when ESMCSA was less than 23.42cm² (P<0.001). Multivariate Cox regression analyses showed that ESMCSA was an independent predictor for 5-year all-cause mortality in COPD patients (P=0.018). Based on the ESMCSA, age, percentage of predicted diffusing lung capacity for carbon monoxide, partial pressure of oxygen as well as carbon dioxide in the arterial blood, a nomogram prediction model for 5-year survival probability in COPD was established. The concordance indexes for the nomogram in the training and validation cohorts were 0.852 and 0.890, respectively. The calibration curve of the nomogram model was close to the ideal curve, and its clinical decision curve showed a good clinical application value.

Conclusion: ESMCSA is a significant predictor for 5-year all-cause mortality in COPD patients, and the nomogram model based on ESMCSA has a certain reference value for predicting COPD prognosis.