Modelling therapeutic strategies in the treatment of osteoarthritis: an economic evaluation of meloxicam versus diclofenac and piroxicam.

OBJECTIVE: To assess the economic efficiency of meloxicam, a cyclo-oxygenase (COX)-2 selective inhibitor, versus diclofenac and piroxicam in the UK for the treatment of patients with osteoarthritis and the impact on the NHS budget of substituting nonselective NSAIDs with meloxicam. Methods and perspective: A decision analytical model was used to compare the effects of 4 weeks' treatment of osteoarthritis with meloxicam (7.5 mg/day), diclofenac (100 mg/day) and piroxicam (20 mg/day). The decision tree was derived by combining best practice and clinical reality. Analysis was from the NHS perspective. The study considered only the direct costs. These included costs for drug acquisition and management of all adverse events, both serious gastrointestinal events requiring hospitalisation, and non-serious events that required maintenance. Resource use and treatment costs were obtained from local and published sources. A range of sensitivity analyses was carried out.
RESULTS: Based on two 4-week large-scale trials, the Meloxicam Large-scale International Study Safety Assessment (MELISSA) and Safety and Efficacy Large-scale Evaluation of COX-inhibiting Therapies (SELECT) trials, and a decision analytical model, the findings suggested that meloxicam had the lowest cost per patient ( pound 30 versus pound 35 for piroxicam and pound 51 for diclofenac [costs presented as 1998 values except for drug costs which were in 2000 values]). The results of the Monte Carlo probabilistic sensitivity analysis, using 4000 samples, suggested that meloxicam was the optimal strategy in the drug treatment of patients with osteoarthritis compared with nonselective NSAIDs both individually and as a group. The cost savings were due to lower levels of serious adverse events accompanied by fewer days in intensive care units and shorter overall duration of hospital stay observed with meloxicam compared with diclofenac and piroxicam in the 4-week trials.
CONCLUSIONS: Based on the 4-week trial period, meloxicam was predicted to be the lowest cost drug therapy, and thus the optimal drug therapy, in the management of patients with osteoarthritis compared with nonselective NSAIDs such as diclofenac and piroxicam. Applying the cost savings per patient derived from the model, switching patients from piroxicam and diclofenac to meloxicam would indicate a cost saving of over pound 25 million per annum. Models such as this can facilitate better clinical guidance and is a useful way of assessing treatment outcomes.