Exacerbation-related burden in patients with severe asthma in South Korea: a population-based cohort study

Background The burden of severe asthma due to asthma exacerbation is increasing. However, recent studies identifying exacerbation-related disease burden among patients with severe asthma in South Korea are lacking. Objective To evaluate the burden of asthma exacerbations in patients with severe asthma in South Korea. Methods A retrospective cohort study using National Health Insurance data from 2016 to 2019 was conducted. Patients with severe asthma were defined as satisfying the following criteria: (1) having been prescribed ≥1 inhaled corticosteroid-long-acting β-2 agonist and long-acting muscarinic antagonist with a diagnosis of asthma; (2) having experienced ≥4 asthma exacerbation events within 1 year, after meeting the first criterion. Exacerbation was defined as a corticosteroid burst. Healthcare utilisation, direct medical costs and case fatality rates related to asthma exacerbations were identified during the follow-up period. Results Outpatient visits accounted for 81.26% of all exacerbation events, followed by general ward hospitalisation (14.55%). The exacerbation-related costs were as follows: outpatient visit, $29.89; emergency room visit, $95.02; general ward hospitalisation, $1929.32; and intensive care unit admission, $7918.86. The case fatality rates were 2.65% for patients with asthma, 3.16% for patients who had exacerbations and 6.96% for patients who had exacerbations with hospitalisation. Conclusion This study is the first population-based cohort study observing exacerbation-related burdens in patients with severe asthma, using recent data and generating real-world evidence. The results of this study can be used as evidence for further research on the burden of asthma and to inform decision-making in healthcare policy.