Objectives Asthma exacerbation, associated with many risks factors, can reflect
management failure. However, little is known about how risk factors are associated with
exacerbation, according to asthma severity. We aimed to investigate differences in risk
factors in patients with different asthma severity and evaluate whether risk factors differed
between frequent exacerbators and patients with single exacerbation. Design Nationwide
population-based observational study. Setting Korean National Sample Cohort database …