Characteristics of Difficult to Treat Asthma in Korea

Background: Difficult-to-treat asthma afflicts a small percentage of the asthma population. However, these patients remain refractory to treat, and account for 40% to 50% of the health costs of asthma treatment, incurring significant morbidity. We conducted a multi-center cross-sectional study to characterize difficult-to-treat asthma in Korea. Methods: Subjects with difficult-to-treat asthma and subjects with controlled asthma were recruited from 5 outpatient clinics of referral hospitals. We reviewed medical records of previous 6 months and obtained patient-reported questionnaires composed of treatment compliance, asthma control, and instruments for stress, anxiety, and depression. Results: We recruited 21 subjects with difficult-to-treat asthma and 110 subjects with controlled asthma into the study. The subjects with difficult-to-treat asthma were associated with longer treatment periods, more increased health care utilization, more medication (oral corticosteroids, number of medication), and more anxiety disorder compared to those of well-controlled asthmatics. There was no difference in age, gender, history of allergy, serum IgE, blood eosinophil count, or body mass index between the 2 groups. Conclusion: Difficult-to-treat asthma is characterized by increased health care utilization and more co-morbidity of anxiety.