Body composition and mortality in idiopathic pulmonary fibrosis (IPF): a prospective cohort study

Background: Low body mass index (BMI) and body composition abnormalities (such as reduced fat free mass: FFM) are associated with poor prognosis in COPD. We assessed the prognostic performance of BMI and FFM in IPF. Methods: We enrolled 181 patients with IPF from respiratory and pulmonary rehabilitation clinics at 2 centres in London, UK. We measured body mass index and fat free mass index (FFMI: FFM normalized to height squared) using bioelectric impedance analysis. The primary outcome was all-cause mortality at 1 year. We calculated hazard ratios (HR) using Cox proportional hazards regression, adjusting for age, sex, BMI, MRC Dyspnoea score and FVC %predicted. Results: During follow-up, we documented 36 (20%) deaths. Neither BMI nor FFMI (as continuous or categorical variables) were associated with all-cause mortality risk on univariable analysis (Table). Only FVC %predicted was independently associated with mortality on multivariate analysis. Conclusion: Body composition variables are not associated with mortality in IPF.