A Retrospective Claims Database Study to Clarify Treatment Reality of Asthma Patients Before and After Referral to a Specialist.

Purpose: Japanese guidelines recommend that patients with uncontrolled asthma be referred by non-specialists to specialists (allergists and/or pulmonologists). This study investigated the reality of clinical practice in asthma patients referred to specialists in Japan. Patients and Methods: This was a retrospective, observational cohort study of asthma patients in a health insurance claim database (Cross Fact) referred from facilities with non-specialists to those with specialists from January 2016 to December 2018. The referred asthma patients were defined as patients with ≥4 inhaled corticosteroid (ICS)-containing prescriptions during a 1-year baseline period, with an asthma diagnosis, and who had visited a facility with specialists. Asthma exacerbation, maintenance treatment, laboratory tests, and medical procedures before and after referral were analyzed. Results: Data for 2135 patients were extracted, of which 420 with referral codes were analyzed. The proportion of patients with asthma exacerbations was 50.2% (95% confidence interval [CI]: 45.4-55.1%) before referral and 37.4% (95% CI: 32.7-42.2%) after, a significant decrease (P<0.001; McNemar test). The proportions of patients prescribed ICS alone, long-acting beta-agonists (LABA), and ICS/LABA were lower after referral than before, but the proportions of patients prescribed long-acting muscarinic antagonists (LAMA), ICS/LABA/LAMA, and biologics increased after referral. More asthma-related laboratory tests were performed after referral, and spirometry incidence increased from 16.4% before referral to 51.4% after referral. Conclusion: This study shows a decrease in asthma exacerbations, change in asthma treatments, and increase in laboratory tests after referral to a specialist, suggesting that referrals to specialists lead to better management of asthma.