Body composition changes successfully classify prognosis in patients with mycobacterium avium complex lung disease.

Objectives: Loss of body weight, a manifestation of cachexia, is frequently found in patients with Mycobacterium avium complex lung disease (MAC-LD) and known as a prognostic determinant. However, the involvement of body composition changes in the prognosis of patients with MAC-LD remains unclear.
Methods: The cross-sectional-area of the erector spinea muscle (ESM _CSA ) and mean attenuation of the erector spinae muscles (ESM _MA ) in patients with MAC-LD, as determined by computed tomography imaging, were measured in two independent cohorts (137 and 111 patients, respectively).
Results: Patients with MAC-LD showed significantly smaller ESM _CSA together with lower body mass index (BMI), but no difference in ESM _MA in both cohorts compared with controls. Smaller ESM _CSA , body mass index decline, and decreased ESM _MA were associated with worse survival in the patients. Among them, decreased ESM _MA showed prognostic significance in the multivariate analyses. Importantly, assessment by ESM _MA together with BMI successfully divided the patients into three groups with distinct prognoses.
Conclusion: Changes in body composition, especially decreased ESM _MA , had prognostic significance in patients with MAC-LD. Additionally, combined assessment of ESM _MA and BMI accurately predicted the prognosis of MAC-LD, which may be a helpful tool for disease management.
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