OBJECTIVES: A local clinical trial showed that celecoxib therapy was comparable in efficacy to diclofenac plus omeprazole in preventing recurrent gastrointestinal bleeding in high-risk patients. The objective of the present study is to evaluate the economic impact of celecoxib therapy versus diclofenac plus omeprazole for the treatment of arthritic patients with high risks. METHODS: A decision tree was designed to analyze the economic and clinical outcomes of a randomized controlled clinical trial. Two hundred and eighty-seven patients with arthritis and active ulcer bleeding were recruited. After ulcer healing had been confirmed, the patients were randomized to receive either celecoxib 200mg twice daily or diclofenac twice daily plus 20mg of omeprazole daily for 6 months. The clinical outcome was incidence of ulcer bleeding. The healthcare resource consumption associated with study patients was retrieved from the trial case reports. The direct medical costs were estimated based upon symptom-driven healthcare resources utilization. The study was performed from the perspective of a public health organization in Hong Kong. RESULTS: Seven out of 144 patients (4.9%) in the celecoxib group and 9 out of 143 patients (6.3%) in the diclofenac group experienced ulcer bleeding. The mean cost for management of ulcer bleeding was HKD19,434 (95% CI: HKD10,950-27,918) (1US=7.8HKD). The mean total cost of routine follow-up and differential diagnosis during study period for patients in the celecoxib group and diclofenac group were HKD10,211 (95% CI: HKD9,807-10,615) and HKD11,505 (95% CI: HKD11,140-11,870), respectively. The results of the decision tree analysis showed that the direct cost per patient was HKD11,155 and HKD12,729 for the celecoxib and diclofenac groups, respectively. No threshold value was identified by sensitivity analysis. CONCLUSION: Based on the analysis of the data obtained from a large clinical trial, celecoxib was as safe as diclofenac with omeprazole but appeared to cost less for the treatment of arthritis in a group of high-risk Chinese patients.