Body mass index as a predictor of mortality in bronchiectasis: A nationwide population-based study

Introduction The prognosis of bronchiectasis is not well known. The purpose of this study was to evaluate the association between body mass index (BMI) and mortality in bronchiectasis using a large nationwide population-based cohort. Material and methods Using the National Health Insurance Service-Health Screening Cohort in Korea, individuals with bronchiectasis were identified from 2004 to 2006 and monitored for up to 10 years. Mortality in bronchiectasis was analyzed based on a BMI score 25.0 kg/m2 (obese). Results A total of 2769 individuals with bronchiectasis were included. The underweight, normal weight, overweight, and obese accounted for 5.1%, 40.4%, 25.4%, and 29.3% of all patients with bronchiectasis, respectively. Compared to normal weight, underweight in bronchiectasis was associated with increased all-cause mortality (hazard ratio [HR] = 2.60; 95% confidence interval [CI] = 1.92–3.54), while obese was associated with decreased all-cause mortality (HR = 0.71; 95% CI = 0.55–0.93). This relationship between BMI and mortality was more prominent in respiratory disease-related mortality. Conclusions BMI is a predictor of mortality in bronchiectasis. Underweight is associated with increased mortality among individuals with bronchiectasis while obese is associated with decreased mortality.