Korean cost-effectiveness analysis of NSAIDs, NSAIDs with co-treatments to prevent gastrointestinal toxicity, and COX-2 specific inhibitors in the treatment of rheumatoid arthritis

Background : Nonsteroidal anti-inflammatory drugs (NSAIDs) are used in nearly every patient with rheumatoid arthritis (RA) but their use can be associated with gastrointestinal (GI) side effects, which may be prevented with prophylactic prescription of misoprostol and omeprazole. Recently marketed COX-2 specific inhibitor (COX-2) affords protection against gastropathy. This study was performed to assess Korean cost-effectiveness of NSAIDs, NSAIDs with co-treatments to prevent GI toxicity, and COX-2 in the treatment of RA, and compare it with American cost-effectiveness analysis. Methods : Markov (state-transition) models were used to simulate a cohort of RA patients with approximately 2.5:1 female to male ratio and 50 years, taking disease modifying antirheumatic drugs, low dose steroid (prednisone ≤10 mg/day) and one of the following strategies: 1) NSAIDs without prophylaxis, 2) NSAIDs with misoprostol, 3) NSAIDs with proton pump inhibitor (PPI), or 4) COX-2. Data on incidence, USA cost and consequences of adverse events from treatments were taken from the literature. Treatment costs of adverse events in Korea were calculated based on each disease code. Health effects were expressed as quality-adjusted life years (QALYs). Sensitivity analyses of probability of GI complication and cost were performed. Costs and health outcomes were discounted at a rate of 3% per year. Results : Among the strategies to prevent GI toxicity, PPI was the most cost-effective strategy in Korea and COX-2 was in USA, respectively. The incremental C/E (cost/effectiveness) ratio between PPI and no prophylaxis was 38,068×103￦/QALY (32,044$/QALY) in Korea. The incremental