Changes in disease burden and treatment reality in patients with severe asthma

Background Biologics are clinically available for patients with severe asthma, but changes in asthma control over time are unknown. We examined changes in disease burden and treatment in severe asthma patients. Methods This retrospective study used a Japanese health insurance database (Cross Fact) and included patients aged ≥16 years treated continuously with an inhaled corticosteroid (ICS) for a diagnosis of asthma in each calendar year from 2015 to 2019. Severe asthma was defined as annual use of high-dose ICS plus one or more asthma controller medications four or more times, oral corticosteroids for ≥183 days, or biologics for ≥16 weeks. Changes in asthma exacerbations, prescriptions, and laboratory testing were examined. Results Demographic characteristics were similar throughout the study. The number and proportion of patients with severe asthma among those with asthma increased (2724; 15.3% in 2015 vs 4485; 19.0% in 2019). The proportion of severe asthma patients with two or more asthma exacerbations decreased from 24.4% to 21.5%. Odds ratios (95% confidence interval) of ≥2 asthma exacerbations in each year compared with 2015 were 0.96 (0.85–1.08) in 2016 and 0.86 (0.76–0.97) in 2017, with significant reductions observed in subsequent years. Short-acting beta agonists and oral corticosteroid prescriptions for asthma exacerbations decreased and long-acting muscarinic antagonist and biologic prescriptions for maintenance treatment increased. Conclusions This study showed improvements in disease burden and treatment in severe asthma patients. There remains an unmet medical need for patients with severe asthma, given the proportion who continue to have asthma exacerbations.