Quantitative computed tomography measures of skeletal muscle mass in patients with idiopathic pulmonary fibrosis according to a multidisciplinary discussion diagnosis: A retrospective nationwide study in Japan

Abstract Background Idiopathic pulmonary fibrosis (IPF) is a progressive disease often accompanied by skeletal muscle wasting. We investigated whether skeletal muscle mass and muscle attenuation on computed tomography (CT) are predictors of mortality in IPF patients, using a nationwide cloud-based database and web-based multidisciplinary discussion (MDD) system. Methods IPF patients diagnosed using MDD from April 2009 to March 2014 were included. We analyzed the cross-sectional area (CSA) of the erector spinae muscle (ESMCSA) and the pectoralis muscle (PMCSA), muscle attenuation of the ESM (ESMMA), and PM (PMMA) on single-slice axial CT. Survival probability was assessed using the Kaplan–Meier method and compared by the log-rank test. Multivariate Cox proportional hazards models were used to evaluate the relationship among the ESMCSA, PMCSA, ESMMA, PMMA, clinical parameters, and prognosis. Results A total of 199 IPF patients were enrolled. Seventy-four patients died during the study period and the most frequent cause was acute exacerbation (13.1%). The group with the lowest quartile of ESMCSA had significantly worse survival than other groups (P = 0.009). Survival rates of the groups with the lowest quartile of PMCSA, lower ESMMA, and lower PMMA did not differ from those of other groups. According to multivariate analysis, ESMCSA  Conclusions Low ESMCSA on CT images may be a strong risk factor for all-cause mortality in IPF patients based on MDD diagnosis.