Objective: In patients with uncontrolled asthma, despite management with high doses of inhaled corticosteroids, the additional use of omalizumab and tiotropium is recommended. Omalizumab is an expensive medication and doubts arise as to whether the benefit of this drug outweighs the additional expense of the drug. The purpose of this study was to assess the cost-effectiveness of tiotropium versus omalizumab as add-on therapies to ICS + LABA for patients with uncontrolled allergic asthma.

Methods: A probabilistic Markov model was created to estimate the cost and quality-adjusted life years (QALYs) of patients with uncontrolled allergic asthma in Colombia. Total costs and QALYs of three interventions including standard therapy (ICS + LABA), add-on therapy with tiotropium, and add-on therapy with omalizumab, were calculated over a 10-year time horizon. Multiple sensitivity analyses were conducted. Cost-effectiveness was evaluated at a willingness-to-pay value of $19,000.

Results: The model showed that tiotropium was associated with lower cost than standard therapy and omalizumab (US$5590 vs. US$5693 vs. U$18,154 average annual cost per patient), and higher QALYs (11.8 vs. 11.3 vs. 11.9) average per patient), showing dominance respect to standard therapy. The probability that tiotropium provides a more cost-effective use of resources compared with standard therapy exceeds 99% for willingness-to-pay threshold.

Conclusion: Add-on therapy with tiotropium was a cost-effective alternative to omalizumab and standard therapy for uncontrolled allergic asthma. Our study provides evidence that should be used by decision-makers to improve clinical practice guidelines and should be replicated to validate their results in other middle-income countries.

Keywords: Markov model; Omalizumab; cost-effectiveness analysis; decision analysis; uncontrolled asthma.