Quantitative CT-derived small pulmonary vessel and erector spinae muscle parameters associated with acute exacerbation in COPD patients from a cold region: a dual-center study

Abstract

Introduction To investigate the association of quantitative CT-derived erector spinae muscle and small pulmonary vessel parameters with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in a cold-region population and construct a combined model to evaluate their joint discriminative value. Methods This retrospective dual-center study included 273 patients with COPD from two centers in a cold region of northern China and divided them into non-AECOPD and AECOPD groups. Clinical characteristics, pulmonary function, and quantitative CT parameters, including erector spinae muscle cross-sectional area (CSA), volume, muscle attenuation, CSA/BMI, CSA × CT, and the percentage of small pulmonary vessel area <5 mm2 (%Vessel < 5), were collected. Factors independently associated with AECOPD were identified using logistic regression, and model performance was assessed by ROC analysis, nomogram, decision curve analysis, and calibration curve. Results Compared with the non-AECOPD group, the AECOPD group had significantly lower CSA, volume, muscle attenuation, CSA/BMI, CSA × CT, and %Vessel < 5 (all P < 0.05). After adjustment for age, smoking history, pulmonary function, and center effect, %Vessel < 5 (OR = 0.938, P < 0.001) and CSA/BMI (OR = 0.065, P < 0.001) remained independently associated with lower odds of AECOPD, whereas conventional clinical variables were not independently significant. Bootstrap validation showed stable estimates. The combined model showed the highest discrimination, with an AUC of 0.806 (95% CI: 0.749–0.864), compared with %Vessel < 5, CSA/BMI, and FEV1%pred alone. At the optimal cutoff of 0.843, sensitivity was 62.3% and specificity was 89.7%. Decision curve and calibration analyses showed favorable clinical utility and calibration. Conclusion Quantitative CT-derived CSA/BMI and %Vessel < 5 are independently associated with AECOPD and may provide complementary imaging information for characterizing patients with COPD.