Cost-Effectiveness of Tiotropium in Elderly Patients with Severe Asthma Using Real-World Data

Background: Tiotropium has the potential to alleviate asthmatic symptoms caused by the aging of lungs. However, few studies have focused on specific treatments for elderly patients with asthma. Objectives: To estimate the cost-effectiveness of adding tiotropium to inhaled corticosteroids and long-acting beta-agonists in elderly patients with severe asthma using real-world data. Methods: Phase I was a retrospective cohort study using the National Health Insurance claims data to measure clinical and economic outcomes. In phase II, a Markov model was constructed to evaluate cost-effectiveness from Korean health care system perspective, based on phase I, including 2 health states, and an asthma exacerbation event. We estimated cost given in 2018 US dollars, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio. Subgroup analyses for patients with poorly controlled symptoms (frequent short-acting beta-agonist users; frequent exacerbators) were performed. Results: In elderly patients with severe asthma, the incremental cost and effectiveness in the tiotropium group compared with the inhaled corticosteroid and long-acting beta-agonist group were $2281 and 0.038 QALYs, respectively. The incremental cost-effectiveness ratio was $60,074/QALY, indicating that the addition of tiotropium is not a cost-effective alternative. Meanwhile, 2 subgroups with poorly controlled symptoms showed that adding tiotropium is a cost-effective alternative (frequent short-acting beta-agonist users $4078/QALY; frequent exacerbators $8332/QALY). Conclusions: Tiotropium shows a higher cost-effectiveness profile when applied to elderly patients with uncontrolled symptoms. These results using real-world evidence provide information beyond the clinical outcomes reported by randomized controlled trials, providing a complementary ground in establishing the reimbursement criteria of tiotropium for elderly patients with severe asthma.