Objective:To explore the correlation between muscle CT measurement parameters, energy expenditure and acute exacerbation in patients with stable chronic obstructive pulmonary disease (COPD).Methods:The clinical data of 146 patients with stable COPD from March 2020 to November 2021 in Lu′an Hospital Affiliated to Anhui Medical University (Lu′an People′s Hospital) were retrospectively analyzed. The clinical data were recorded; the lung function was measured by bronchodilator test. The cross-sectional area and CT value of the pectoral muscle were measured by reconstructed CT images of the mediastinum; the total energy consumption was calculated by Weir formula. Acute exacerbations within 3 and 12 months were recorded. Multivariate Logistic regression was used to analyze the independent risk factors for acute exacerbation in patients with stable COPD. The receiver operating characteristic (ROC) curve was used to analyze the efficacy of total energy expenditure, pectoral muscle cross-sectional area and pectoral muscle CT value for predicting acute exacerbation in patients with stable COPD.Results:Among 146 patients with stable COPD, 38 cases (26.03%) developed acute exacerbation within 3 months (acute exacerbation group), and 108 cases (73.97%) did not develop acute exacerbation (non-acute exacerbation group). The proportion of age<60 years old, rate of acute exacerbation within 12 months and rate of pulmonary function grading Ⅲ to Ⅳ in acute exacerbation group were significantly higher than those in non-acute exacerbation group: 71.05% (27/38) vs. 47.22% (51/108), 52.63% (20/38) vs. 30.56% (33/108) and 63.16% (24/38) vs. 37.96% (41/108), the total energy consumption, pectoral muscle cross-sectional area and pectoral muscle CT value were significantly lower than those in non-acute exacerbation group: (2 036.28 ± 163.13) J/d vs. (2 389.59 ± 204.71) J/d, (28.79 ± 3.45) cm 2 vs. (31.61 ± 4.56) cm 2 and (29.79 ± 3.06) HU vs. (34.52 ± 4.38) HU, and there were statistical differences ( P<0.05 or <0.01). Multivariate Logistic regression analysis result showed that age ≥60 years old, lower total energy expenditure, smaller pectoral muscle cross-sectional area and lower pectoral muscle CT value were independent risk factors for acute exacerbation in patients with stable COPD ( OR = 26.493, 1.015, 1.245 and 1.437; 95% CI 3.745 to 187.405, 1.008 to 1.022, 1.002 to 1.546 and 1.109 to 1.861; P<0.01 or <0.05). The ROC curve analysis result showed that combined prediction of the total energy consumption, pectoral muscle cross-sectional area and pectoral muscle CT value for acute exacerbation in patients with stable COPD had the largest area under the curve (0.962), with a sensitivity of 86.1%, a specificity of 80.8%, and the optimal cutoff values of 2 206.12 J/d, 32.39 cm 2 and 31.63 HU, respectively. Conclusions:The elderly age, smaller pectoral muscle cross-sectional area, lower pectoral muscle CT value and lower total energy expenditure are independent risk factors for acute exacerbation in patients with stable COPD. The combination of pectoral muscle cross-sectional area, pectoral muscle CT value and total energy expenditure has a good predictive effect on the risk of acute exacerbation in patients with stable COPD, and relevant indexes can be paid attention to in clinical treatment.