Abstract
Add-on therapy with tiotropium was cost-effective when added to usual care in patients who remain uncontrolled despite treatment with medium or high-dose ICS/LABA in a middle-income country. BACKGROUND: A significant proportion of asthma patients remain uncontrolled despite inhaled corticosteroids and long-acting beta-agonists. Some add-on therapies, such as tiotropium bromide, have been recommended for this subgroup of patients. This study aimed to assess the cost-effectiveness of tiotropium as an add-on therapy to inhaled corticosteroids and long-acting b2 agonists for patients with severe 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 include standard therapy with inhaled corticosteroids and long-acting bronchodilators versus add-on therapy with tiotropium. Multiple sensitivity analyses were conducted. Cost-effectiveness was evaluated at a willingness-to-pay value of $5180. RESULTS: The expected incremental cost per QALY (ICER) is estimated at US$-2637.59. There is a probability of 0.77 that tiotropium + ICS + LABA is more cost-effective than ICS + LABA at a threshold of US$5180 per QALY. The strategy with the highest expected net benefit is Tiotropium, with an expected net benefit of US$800. Our base-case results were robust to parameter variations in the deterministic sensitivity analyses. CONCLUSION: Add-on therapy with tiotropium was cost-effective when added to usual care in patients who remain uncontrolled despite treatment with medium or high-dose inhaled corticosteroids and long-acting bronchodilators. 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.