Background: Little is known about the combination of different medications in chronic obstructive pulmonary disease (COPD). This study determined the cost effectiveness of adding salmeterol (S) or fluticasone/salmeterol (FS) to tiotropium (T) for COPD.
Methods: This concurrent, prospective, economic analysis was based on costs and health outcomes from a 52 week randomised study comparing: (1) T 18 microg once daily + placebo twice daily (TP group); (2) T 18 microg once daily + S 25 microg/puff, 2 puffs twice daily (TS group); and (3) T 18 microg once daily + FS 250/25 microg/puff, 2 puffs twice daily (TFS group). The incremental cost effectiveness ratios (ICERs) were defined as incremental cost per exacerbation avoided, and per additional quality adjusted life year (QALY) between treatments. A combination of imputation and bootstrapping was used to quantify uncertainty, and extensive sensitivity analyses were performed.
Results: The average patient in the TP group generated CAN$2678 in direct medical costs compared with $2801 (TS group) and $4042 (TFS group). The TS strategy was dominated by TP and TFS. Compared with TP, the TFS strategy resulted in ICERs of $6510 per exacerbation avoided, and $243,180 per QALY gained. In those with severe COPD, TS resulted in equal exacerbation rates and slightly lower costs compared with TP.
Conclusions: TFS had significantly better quality of life and fewer hospitalisations than patients treated with TP but these improvements in health outcomes were associated with increased costs. Neither TFS nor TS are economically attractive alternatives compared with monotherapy with T.