Introduction: An important proportion of asthma patients remain uncontrolled despite using inhaled corticosteroids and long-acting beta-agonists. Some add-on therapies, such as tiotropium bromide has been recommended for this subgroup of patients. The purpose of this study was to assess the cost-effectiveness of tiotropium as add-on therapies to ICS + LABA for children and adolescents with uncontrolled allergic asthma.
Methods: A probabilistic Markov model was created to estimate the cost and quality-adjusted life-years (QALYs) of patients with severe asthma in Colombia. Total costs and QALYS of two interventions including standard therapy (ICS + LABA), and add-on therapy with tiotropium, were calculated over a time horizon from 6 to 18 years. Probability sensitivity analyses were conducted.
Results: For a patient with severe asthma, our Markov model showed that compared to standard therapy, add-on therapy with tiotropium was associated with higher treatment costs and QALY. The incremental cost-effectiveness ratio estimated was US$2,017 in the probabilistic model after Monte-Carlo simulation. Our base-case results were robust to variations in all assumptions and parameters. The incremental net monetary benefit of US$327 with a 95% credible interval of US$396 to US425.
Conclusion: Add-on therapy with tiotropium was cost-effective when added to usual care in children and adolescents with severe asthma who remained uncontrolled despite treatment with medium or high-dose ICS/LABA. 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; Tiotropium; cost-effectiveness analysis; decision analysis; uncontrolled asthma.