Relationship of clinical factors to the use of Cox-2 selective NSAIDs within an arthritis population in a large HMO.

OBJECTIVE To investigate the degree to which physicians use clinical factors to focus use of Cox-2 selective NSAIDs within an arthritis population. METHODS Diagnostic codes in the medical records of a large group-model HMO in northern California with approximately 3 million members were examined to identify patients with either rheumatoid arthritis (RA) or non-RA (osteoarthritis or degenerative joint disease). RA and non-RA patients were stratified in deciles of relative risk for gastrointestinal (GI) complications according to patient characteristics identified on the Standardized Calculator of Risk for Events (SCORE) that were associated with use of Cox-2 selective NSAIDs. (The SCORE tool stratifies patients by risk of serious GI complications using patient characteristics that are assigned points during an office visit, including age, health status, diagnosis of rheumatoid arthritis, corticosteroid use, and history of GI ulcer or bleed.) The second stage of analysis examined the percentage of arthritis patients in each SCORE-risk decile who received a Cox-2 selective NSAID, lower-risk NSAID, or traditional NSAID during calendar year 1999. RESULTS The study population consisted of 144,360 members with an arthritis diagnosis, approximately 4.8% of members in this HMO. The mean age was 62.8 years (SD = 14.1), 61% were female, 10,449 (7%) had rheumatoid arthritis (RA), and 133,911 (93%) had non-rheumatoid arthritis. A diagnosis of RA was the most significant predictor of Cox-2 NSAID use (OR=2.4; 95% CI=1.6-3.5), followed by a history of GI problems (OR=1.5; 95% CI=1.4- 1.6). Female gender, chronic steroid use, and age each increased the odds of receiving a Cox-2 selective NSAID by about 35% (P<0.001 for all). Approximately 8.3% of patients in the highest decile of risk and 1.5% of patients in the lowest decile of risk received a Cox-2 selective NSAID. CONCLUSIONS Clinical characteristics of patients identified on the SCORE (GI-risk) tool were strongly associated with use of Cox-2-selective NSAIDs in this HMO. A 5.5-fold difference in utilization of Cox-2 selective NSAIDs was found among patients determined to be in the highest-risk decile versus patients in the lowest-risk decile. Future research should investigate how nonclinical factors play a role in the treatment decisions made by physicians.