Early decrease in erector spinae muscle area and future risk of mortality in idiopathic pulmonary fibrosis

Computed tomography (CT) assessment of the cross-sectional area of the erector spinae muscles (ESM_CSA) can be used to evaluate sarcopenia and cachexia in patients with lung diseases. This study aimed to confirm whether serial changes in ESM_CSA are associated with survival in patients with idiopathic pulmonary fibrosis (IPF). Data from consecutive patients with IPF who were referred to a single centre were retrospectively reviewed. We measured the ESM_CSA at the level of the 12th thoracic vertebra on CT images at referral and 6 months later (n = 119). The follow-up time was from 817-1633 days (median, 1335 days) and 59 patients (49.6%) died. A univariate Cox regression analysis showed that the decline in % predicted forced vital capacity (FVC) (Hazard ratios [HR] 1.041, 95% confidence interval [CI] 1.013-1.069, P = 0.004), the decline in body mass index (BMI) (HR 1.084, 95% CI 1.037-1.128; P < 0.001) and that in ESM_CSA (HR 1.057, 95% CI 1.027-1.086; P < 0.001) were prognostic factors. For multivariate analyses, the decline in ESM_CSA (HR 1.039, 95% CI 1.007-1.071, P = 0.015) was a significant prognostic factor, while those in % FVC and BMI were discarded. Early decrease in ESM_CSA may be a useful predictor of prognosis in patients with IPF.