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

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.

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).

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.

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.