AN ECONOMIC COST ANALYSIS OF ETORICOXIB VERSUS INDOMETHACIN IN THE TREATMENT OF ACUTE GOUTY ARTHRITIS IN THE UK

Background: The prevalence of gout in the UK is about 0.95% in women and 1.64% in men (1), with an increasing gout attack rate in the elderly. Indomethacin is considered the gold standard therapy for gout, but its use is associated with adverse experiences (AEs). Etoricoxib, the only Cox-2 selective inhibitor currently licensed for the treatment of acute gouty arthritis, has been demonstrated in two clinical trials to be efficacious in the treatment of gout.Objectives: To evaluate the total economic cost of etoricoxib versus indomethacin in the treatment of acute gouty arthritis in the UK.Methods: An economic model was developed based on two clinical trials comparing etoricoxib 120mg with indomethacin 150mg daily in the treatment of acute gout. The trials demonstrated similar efficacy, but a reduced incidence of AEs favouring etoricoxib over indomethacin. Of the patients included in the two trials, 94% were male and 14% were 65 years of age or older. The model assumed an average of 4 gout attacks per patient per year, treated for a period of 7 days per attack. For the first gout attack patients were assumed to consult a general practitioner (GP) and receive a prescription for a 21-day supply of either etoricoxib 120mg (one 7-day pack plus 2 refills) or indomethacin 150mg daily, sufficient for the self-treatment of 2 additional gout attacks. At the fourth gout attack patients were assumed to consult the GP again and get prescribed an additional 7 days of etoricoxib/indomethacin treatment. The analysis reports the expected total cost of treatment including drug costs and costs for the treatment of serious and non-serious AEs related to treatment, the frequency of which was based on the clinical trials. Information on treatments of AEs, the patient''s probability of seeking medical attention (range 20-50% for individual AEs), and the probability of switching gout therapy after an AE were obtained from gout experts in the UK. Side-effects of second line therapies were not modelled. Costs of AEs were based on Mediplus data (2); etoricoxib costs were obtained from public sources (3); and costs for GP consultations were obtained from Curtis et al (4). Several sensitivity analyses were performed: number of GP visits per year, cost of GP visits, probability of seeking medical attention for individual AEs, duration of AE treatment, and impact of including indirect costs related to AEs.Results: After 4 gout attacks the expected total cost, including the treatment of drug-related AEs, were £64.40 and £48.93 per patient per year for etoricoxib and indomethacin, respectively, resulting in an incremental cost per patient per year of £15.47. This result does not incorporate the impact of AEs on patients'' quality of life or inability to work (indirect costs). If all AEs are considered, including those unlikely to be drug-related, the cost difference ranges from £15.39 (0-50% probabilty of treatment for different non-drug-related AEs) to £15.40 (5% probabilty of treatment for all non-drug-related AEs).Conclusion: Though the treatment of acute gout with etoricoxib is associated with higher drug costs than for indomethacin, a difference of £17.64 for 28 days of treatment (£22.96 etoricoxib, £5.32 indomethacin), some of these additional drug costs are offset by the reduced costs related to drug-related AEs. In addition the reduction in drug-related AEs may have a positive effect on patients'' quality of life.References: 1. Harris C. et al. J Clin Epidemiol 1995 9: 1153-1158.2. Mediplus; IMS disease analyser3. IMS data, IMS4. Curtis L, Netten A; PSSUR 2004Citation: Ann Rheum Dis, volume 64, supplement III, year 2005, page 399Session: Health services, economics and outcome research 1