Cost-effectiveness analysis of roflumilast/tiotropium therapy versus tiotropium monotherapy for treating severe-to-very severe COPD

Abstract

Objective:To conduct a cost-effectiveness analysis comparing roflumilast/tiotropium therapy vs tiotropium monotherapy in patients with severe-to-very severe COPD.Methods:The economic evaluation applied a disease-based Markov cohort model with five health states: (1) severe COPD, (2) severe COPD with a history of severe exacerbation, (3) very severe COPD, (4) very severe COPD with a history of severe exacerbation, and (5) death. Within a given health state, a patient may have a mild/moderate or severe exacerbation or die. Data from roflumilast clinical trials and published literature were used to populate model parameters. The model calculated health outcomes and costs for roflumilast/tiotropium therapy vs tiotropium monotherapy over a 5-year horizon. Incremental cost and benefits were then calculated as cost-effectiveness ratios, including cost per exacerbation avoided and cost per quality adjusted life year ($/QALY).Results:Over a 5-year horizon, the estimated incremental costs per exacerbation and per severe exacerbation avoided were $589 and $5869, respectively, and the incremental cost per QALY was $15,815. One-way sensitivity analyses varying key parameters produced an incremental cost per QALY ranging from $1963–$32,773.Limitations:A number of key parameters used in the model were obtained from studies in the literature that were conducted under different contexts. Specifically, the relative risk estimate for severe COPD patients originates from a small trial not designed to demonstrate the impact of roflumilast on frequency of exacerbations. In addition, the model extrapolates the relative risk estimates over periods of 5–30 years, even though the estimates were only observed in trials that spanned less than a year.Conclusions:The addition of roflumilast to tiotropium is cost-effective for the treatment of severe to very severe COPD patients.