Prevalence of asymptomatic bronchiectasis and associations among the health screening population in South Korea

Despite the burden of bronchiectasis, there is little data from South Korea regarding asymptomatic bronchiectasis. We aimed to investigate the prevalence of bronchiectasis based on computed tomography (CT) findings, with emphasis on asymptomatic bronchiectasis (CT-proven) and its related factors. We analysed data of individuals who underwent chest CT at a South Korean health screening centre from 2016 to 2017. The prevalence of bronchiectasis was evaluated and adjusted by sex, age, and corresponding year for the Korean general population. Logistic regression analysis was performed to identify factors related to asymptomatic bronchiectasis by comparison between a group without bronchiectasis and a group with symptomatic bronchiectasis. Among the 27 617 subjects screened, 1005 were diagnosed with bronchiectasis based on CT findings, representing an adjusted prevalence of 2329 out of 100 000. The adjusted prevalence of asymptomatic bronchiectasis was 1235 out of 100 000, and that of symptomatic bronchiectasis was 1094 out of 100 000. Compared with the non-bronchiectasis group, the factors related to asymptomatic bronchiectasis were female sex (OR 1.41; 95% CI 1.18–1.70), older age (OR 1.06; 95% CI 1.05–1.07), comorbid liver disease (OR 1.32; 95% CI 1.07–1.63) or COPD (OR 4.99; 95% CI 2.88–8.64), history of tuberculosis (OR 1.98; 95% CI 1.46–2.68) and low forced expiratory volume in 1 s (FEV(1); OR 0.99; 95% CI 0.98–0.998). In South Korea, the prevalence of asymptomatic bronchiectasis appeared higher than that of symptomatic bronchiectasis. Female sex, older age, liver disease, COPD, history of tuberculosis and low FEV(1) may be the factors related to asymptomatic bronchiectasis.