Economic evaluation of celecoxib, a new cyclo-oxygenase 2 specific inhibitor, in Switzerland.

OBJECTIVE: The aim of this study was to predict the cost effectiveness of celecoxib, a cyclo-oxygenase 2 (COX-2) specific inhibitor, in the treatment of arthritis patients in Switzerland.
METHODS: We applied a decision analytical model to compare the effects of 6 months' treatment with the following: (i) celecoxib; (ii) nonsteroidal anti-inflammatory drug (NSAID) alone; NSAID protected with (iii) proton pump inhibitor (PPI), (iv) histamine H2 receptor antagonist (H2RA), or (v) misoprostol; and (vi) diclofenac/misoprostol. Treatment costs included drug acquisition and the management of gastrointestinal (GI) adverse effects, classified as GI discomfort, symptomatic ulcer, anaemia and serious GI events (requiring hospitalisation). Probabilities were derived from celecoxib clinical trials and the literature. Drug utilisation patterns and treatment costs reflecting Swiss practice were obtained from local sources. Analysis was from the public health insurers' perspective. A range of sensitivity analyses was performed.
RESULTS: For the base case of patients at typical risk (0.56% per 6 months) of serious GI events, the total expected costs of 6 months' treatment were as follows: celecoxib 435 Swiss francs (SwF); NSAID alone SwF510; diclofenac/misoprostol SwF522; and other protected NSAID regimens between SwF1034 and SwF1415. Celecoxib remained the lowest costing treatment over all categories of GI risk. Celecoxib generated 115 expected adverse events per 1000 patients per 6 months, followed by NSAID + PPI (119), NSAID + H2RA (154), NSAID + misoprostol (202), diclofenac/misoprostol (203), and NSAID alone (220), again for the base case. The cost per adverse event averted for celecoxib compared with NSAIDs alone was estimated in a stochastic version of the model using Monte Carlo simulation. In 95% of 500 iterations, celecoxib was predicted to save both costs and adverse events, thus dominating NSAIDs alone; the maximum cost per adverse event averted was SwF440.
CONCLUSIONS: Celecoxib is predicted to be the most cost effective of the treatments considered for managing arthritis patients in Switzerland. A policy of switching patients from NSAIDs to celecoxib is predicted to be cost saving for public health insurers, while reducing the burden of iatrogenic GI side effects. Greater cost savings would be realised when patients are switched from NSAIDs used with gastroprotective agents. Models such as this can provide a useful but simplified view of treatment outcomes and predicted results require prospective validation in clinical practice.