Quantitative evaluation of muscle mass based on chest high-resolution CT and its prognostic value for tuberculosis: a retrospective study.

Abstract

Objective: This study aims to explore the prognostic value of quantitatively evaluating muscle mass using chest high resolution computed tomography (HRCT) in patients with active tuberculosis (TB).

Methods: This retrospective cohort study collected data from 309 patients with active TB diagnosed at Ningbo No.2 Hospital from 2020 to 2023. Based on the skeletal muscle index (SMI) at the T12 vertebra (with thresholds of <28.8 cm²/m² for men and <20.8 cm²/m² for women), patients were divided into a low muscle mass group and a normal muscle mass group. The study compared baseline characteristics, muscle mass-related indicators, body mass index (BMI), and imaging features between the two groups. The correlation between muscle mass-related indicators, BMI, and TB imaging features and prognosis was analyzed. Receiver operating characteristic (ROC) curve analysis and multivariate logistic regression were used to assess the prognostic value of muscle mass-related indicators and BMI in patients undergoing anti-TB treatment.

Results: A total of 309 patients were included in the study, divided into a normal muscle mass group (n = 229) and a low muscle mass group (n = 80). There was a significant difference in prognosis between the two groups (χ ² test, p < 0.05). Patients in the low muscle mass group were older, had a higher proportion of males, and had a lower BMI (p < 0.05). Additionally, these patients had a higher likelihood of developing pulmonary cavities (p < 0.05). In terms of imaging features, the two groups showed significant differences in the pre-treatment proportion of pulmonary fibrotic bands, ground-glass opacities, consolidation, lesion percentage, and lesion absorption ratio (all p < 0.05). Univariate analysis indicated that both the T12 skeletal muscle index (T12 SMI) and BMI were correlated with TB imaging characteristics (p < 0.05), with T12 SMI showing a stronger correlation than BMI. Multivariable linear regression analysis revealed that after adjusting for age, gender, and T12 skeletal muscle radiation attenuation (T12 SMRA), T12 SMI remained significantly correlated with the whole-lung lesion proportion (β: - 4.56, 95% CI [-5.45 to -3.67]) and lesion absorption ratio (β:0.036, 95% CI [0.031-0.041]). Multivariable logistic regression analysis demonstrated that after accounting for age, gender, T12 SMRA, T12 SMI was significantly associated with the prognosis of TB patients (OR: 20.10, 95% CI [8.81-51.56], p < 0.05), indicating that low T12 SMI is an independent risk factor associated with poor prognosis. ROC curve analysis indicated that T12 SMI may offer advantages over BMI, with an area under the ROC curve (AUC) of T12 SMI (0.761, 95% CI [0.690-0.832]) higher than the AUC of BMI (0.700, 95% CI [0.619-0.781].

Conclusion: Quantitative evaluation of muscle mass using chest HRCT, particularly the T12 SMI, may provide valuable prognostic information for tuberculosis patients, potentially offering advantages over BMI in assessing patient outcomes.