Impact of sarcopenia defined by carina-level skeletal muscle mass on the long-term prognosis of patients with idiopathic pulmonary fibrosis

Sarcopenia, defined using abdominal computed tomography (CT), has been used as a prognostic marker for patients with idiopathic pulmonary fibrosis (IPF). However, no consensus on the impact of sarcopenia as defined using chest CT exists. Therefore, this study aimed to investigate the impact of sarcopenia, defined using CT at the carina-level, on the long-term prognosis of patients with IPF.This single-center retrospective cohort study included 117 patients with IPF. Sarcopenia was defined as skeletal muscle mass measured at the carina-level on chest CT images. All-cause mortality was analyzed using the Kaplan-Meier method, and the log-rank test was used to evaluate the differences between sarcopenia and non-sarcopenia groups. A Cox proportional hazards regression model was used to analyze the impact of sarcopenia on all-cause mortality in model 1 with adjustment for body mass index and gender-age-physiology stage as a confounding factor and in model 2 with sex, age, and% forced vital capacity (FVC).The median follow-up period was 956 days, and 57 deaths were recorded. The sarcopenia group had a significantly lower survival rate than the non-sarcopenia group. The multivariate Cox proportional hazards analysis revealed that sarcopenia was a significant predictor of all-cause mortality in models 1 and 2. In patients with no diffusing capacity for carbon monoxide (DLCO) measurement, sarcopenia was a significant prognostic predictor of all-cause mortality independent of%FVC.Sarcopenia, defined at the carina level, is a risk factor for all-cause mortality in patients with IPF. Assessment of sarcopenia by CT imaging is useful and less burdensome in patients with IPF.