Background: Non-steroidal anti-inflammatory drug (tNSAIDs) or selective COX-II inhibitor (COXIBs) are generally used as the first-line intervention of knee osteoarthritis (OA). Total knee arthroplasty (TKA) is suggested for those who dissatisfy from non-surgical treatment. However, the long-term usage of tNSAIDs may lead to articular cartilage and resulted in higher rate of TKA. The evaluation of real clinical practice needs to be scrutinized as the inappropriate treatment will be socially burden.
Objective: To evaluate cost-utility of selective COX-II inhibitors (COXIBs) compared to traditional NSAIDs in patients with knee osteoarthritis (OA) and to estimate health and economic burden of disease of knee OA.
Material and Method: The present study is an economic evaluation alongside a prospective observational study. The data of cost and treatment outcomes were collected from real clinical practice. EQ-5D questionnaire was employed to calculate utility values at baseline and 6 months after treatment.
Results: Total 939 patients were prescribed tNSAIDs and 380 patients received celecoxib. Eleven cases (1.17%) of all tNSAIDs usages and 3 cases (0.79%); p = 0.56 of celecoxib usages were detected GI complication. Two cases of tNSAIDs group were dead from severe GI bleeding. TKA was markedly reported with 12.99% of tNSAIDs and 9.80% of celecoxib; p = 0.06. QALYs gained from 6 months was 0.34 (+ 0.11) for tNSAIDs and 0.36 (+ 0.11) for celecoxib; p = 0.004. Average direct medical expenses per patient were comparable with 17,468.97 THB for tNSAIDs and 17,495.07 THB for celecoxib. Cost of TKA was a key element in both groups with 90% and 67% of total expenses in tNSAIDs and celecoxib groups, respectively. Incremental cost-effectiveness ratio (ICER) per Quality-adjusted life years (QALY) gained comparing celecoxib and tNSAIDs was 1,382.70 THB.
Conclusion: The finding from our study can be a concrete evidence to support the appropriate future decision of clinical judgment and health care provider.

Keywords: Cost-Utility Analysis, coxib, NSAIDs and TKA