Incremental Cost-Effectiveness Analysis Comparing Rofecoxib with Nonselective NSAIDs in Osteoarthritis

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Abstract
Background: Clinical trials have shown rofecoxib, a selective inhibitor of cyclo-oxygenase-2, to be associated with fewer gastrointestinal complications than nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). Objective: To evaluate the potential clinical and economic consequences of rofecoxib prescription in Ontario, Canada, for patients with osteoarthritis (OA) aged >65 years who did not respond to paracetamol (acetaminophen) therapy. Design: Decision analytic modelling study. Methods: A model was constructed to compare rofecoxib and nonselective NSAIDs with respect to their gastrointestinal complications in patients with OA. The model had a 1-year horizon and considered direct medical costs from the perspective of the Ontario Ministry of Health. Event rates were estimated from a pooled analysis of 8 phase IIb/III clinical trials. The number of perforations, ulcers and bleeds (PUBs) with each strategy was used as the primary measure of effectiveness. Results: In the base-case scenario, the expected total cost per patient-day on nonselective NSAIDs was 1.60 Canadian dollars ($Can) versus $Can1.67 on rofecoxib (1999 values). Rofecoxib was associated with 0.0109 fewer PUBs per patient per year. The incremental cost to avoid 1 additional PUB by substituting rofecoxib for nonselective NSAIDs was $Can2247. The rofecoxib strategy became dominant if a gastroprotective agent was prescribed to more than 27.5% of the patients receiving nonselective NSAIDs. Conclusion: For patients with OAaged >65 years in whom paracetamol therapy has failed, rofecoxib may represent a cost-effective alternative to nonselective NSAIDs. Increased costs for drug acquisition are offset, in part, by avoidance of gastrointestinal complications and reduced use of gastroprotective agents. Rofecoxib may offer increased benefit among patients at a higher risk of serious gastrointestinal events.