Cost Effectiveness of Duloxetine for Osteoarthritis: A Quebec Societal Perspective

Objective. To assess the cost effectiveness of duloxetine compared to other oral postacetaminophen treatments for osteoarthritis (OA) from a Quebec societal perspective. Methods. A cost-utility analysis was performed enhancing the Markov model from the 2008 OA guidelines of the National Institute for Health and Clinical Excellence (NICE). The NICE model was extended to include opioid and antidepressant comparators, adding titration, discontinuation, and relevant adverse events (AEs). Comparators included duloxetine, celecoxib, diclofenac, naproxen, hydromorphone, and oxycodone extended release (oxycodone). AEs included gastrointestinal and cardiovascular events associated with nonsteroidal antiinflammatory drugs (NSAIDs), as well as fracture, opioid abuse, and constipation, among others. Costs and incremental cost-effectiveness ratios (ICERs) were estimated in 2011 Canadian dollars. The base case modeled a cohort of 55-year-old patients with OA for a 12-month period of treatment, followed by treatment from a basket of post-discontinuation oral therapies until death. Sensitivity analyses (one-way and probabilistic) were conducted. Results. Overall, naproxen was the least expensive treatment, whereas oxycodone was the most expensive. Duloxetine accumulated the highest number of quality-adjusted life years (QALYs), with an ICER of $36,291 per QALY versus celecoxib. Duloxetine was dominant over opioids. In subgroup analyses, ICERs for duloxetine versus celecoxib were $15,619 and $20,463 for patients at high risk of NSAID-related AEs and patients ages >= 65 years, respectively. Conclusion. Duloxetine was cost effective for a cohort of 55-year-old patients with OA, and more so in older patients and those with greater AE risks.