Real-world treatment and health care resource use among severe asthma patients in Japan.

Background There are limited studies on healthcare resource use (HCRU) among adult asthma patients in Japan using real-world evidence, and analysis on acute treatment and associated costs stratified by disease severity is further limited. This study aimed to characterize the disease burden of severe asthma patients in Japan in terms of HCRU and comorbid medical conditions, with particular interest in oral corticosteroid (OCS) dependency. Methods This retrospective cohort study of asthma patients used data from a claims database of diagnosis procedure combination hospitals in Japan. The severe asthma cohort included patients treated with OCS for more than 180 days in one year before the index date, with at least one asthma diagnosis claim. Comorbidity and drug use in the look-back period, HCRU, assumed OCS-related adverse events, and asthma exacerbations in the follow-up period were analyzed. Results Costs associated with the treatment of severe asthma were approximately twice that of mild/moderate asthma, and the annual median cost of patients hospitalized due to asthma reached ¥448,000 (USD $4073). Annual asthma exacerbation rate was higher in the severe asthma cohort than in the mild/moderate cohort. Patients with longer OCS use in the previous year had higher risks of secondary adrenal insufficiency, osteoporosis, and pneumonia in the following year. Conclusions OCS use among asthma patients in Japan incurred greater medical and economic burden. Better understanding of the disease characteristics including the severity of asthma and appropriate management of disease burden will lead to more optimal use of healthcare resources in Japan.