An economic assessment of inhaled formoterol dry powder versus ipratropium bromide pressurized metered dose inhaler in the treatment of chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is debilitating and costly to manage. A recent clinical trial concluded that formoterol, a long-acting beta(2)-adrenoceptor agonist, was more clinically effective than inpratropium bromide in the management of COPD.

OBJECTIVE: The aim of this study was to perform an economic assessment of the management of COPD with formeterol versus ipratropium bromide.

METHODS: Assessment were based on the results of a previously published 12-week, multicenter, double-masked, randomized, parallel-group, placebo-controlled clinical trial comparing inhaled formoterol dry powder 12 and 24 microg BID with ipratropium bromide 40 microg QID pressurized metered dose inhaler and with placebo in 780 COPD patients. Treatment costs for study drugs and rescue medications were estimated from resource utilization and average wholesale prices. Costs were assessed with respect to forced expiratory lung volume in 1 second (FEV(1)) and patient-reported quality of life (QOL) as assessed via the St. George's Respiratory Questionnaire. Cost-effectiveness ratios were calculated for each treatment arm and incremental cost-effectiveness ratios (ICERs) were calculated for each treatment relative to the next best alternative. Economic efficiency frontiers were identified. Sensitivity analysis was conducted.

RESULTS: Cost analysis with respect to FEV(1) revealed an economic efficiency frontier formed by placebo, ipratropium bromide 40 microg, and formoterol 12 microg at their respective FEV(1) levels, with cost-effectiveness ratios of $30.18, $53.50, and $142.04, respectively, per FEV(1). The ICER for ipratropium over placebo was $273.03; for formoterol 12 microg over ipratropium, $1611.32. Cost analysis with respect to QOL showed an economic efficiency frontier formed by placebo and formoterol 12 microg at their respective QOL outcomes, with cost-effectiveness ratios of $25.96 and $32.56, respectively, per QOL score change. The cost-effectiveness ratio for ipratropium was $69.40,which was not on the QOL economic efficiency frontier. The ICER for formoterol 12 microg over placebo was $34.51 per QOL score point.

CONCLUSIONS: Formoterol 12 microg provided greater QOL outcome than ipratropium bromide at an additional cost of $554.28 per year. Further research would be necessary to assess whether the differences in outcomes, particularly QOL, observed in the short term with formoterol would lead to favorable long-term health and economic outcomes.