Association of Body Mass Index and Change in Weight with Mortality in Patients with Fibrotic Interstitial Lung Disease.

ABSTRACT Background Mortality risk assessment in interstitial lung disease (ILD) is challenging. Our objective was to determine the prognostic significance of body mass index (BMI) and change in weight in the most common fibrotic ILD subtypes. Research Question Could BMI and weight loss over time be reliable prognostic indicators in patients with fibrotic ILD? Study Design and Methods This observational retrospective multicenter cohort study enrolled patients with fibrotic ILD from the six-center CAnadian REgistry for Pulmonary Fibrosis (CARE-PF, derivation) and the ILD registry at the University of California, San Francisco (UCSF, validation). Patients were subcategorized as underweight (BMI 30kg/m2). Annual change in weight was calculated for all years of follow-up as the slope of best fit using the least square method based on every available measurement. Separate multivariable analyses evaluated the associations of BMI and change in weight with mortality, adjusting for common prognostic variables. Results The derivation and validation cohorts included 1786 and 1779 patients, respectively. Compared to patients with normal BMI, mortality was highest in patients who were underweight (HR 3.19, 95%CI 1.88–5.43, P Interpretation Both BMI and weight loss are independently associated with 1-year mortality in fibrotic ILD. BMI and weight loss may be clinically useful prognostic indicators in fibrotic ILD.