Incremental cost-effectiveness analysis comparing rofecoxib with nonselective NSAIDs in osteoarthritis - Ontario ministry of health perspective

Background: Clinical trials have shown rofecoxib, a selective inhibitor of cyclooxygenase-2, to be associated with fewer gastrointestinal complication s 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) th erapy. Design: Decision analytic modelling study. Methods: A model was constructed to compare rofecoxib and nonselective NSAI Ds with respect to their gastrointestinal complications in patients with OA . The model had a 1-year horizon and considered direct medical costs from t he perspective of the Ontario Ministry of Health. Event rates were estimate d 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 p rimary 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 p er patient per year. The incremental cost to avoid I additional PUB by subs tituting rofecoxib for nonselective NSAIDs was $Can2247. The rofecoxib stra tegy became dominant if a gastroprotective agent was prescribed to more tha n 27.5% of the patients receiving nonselective NSAIDs. Conclusion: For patients with OA aged > 65 years in whom paracetamol therap y has failed. rofecoxib may represent a cost-effective alternative to nonse lective NSAIDs. Increased costs for drug acquisition are offset, in part, b y avoidance of gastrointestinal complications and reduced use of gastroprot ective agents. Rofecoxib may offer increased benefit among patients at a hi gher risk of serious gastrointestinal events.