Predictors of the selection of coxibs over nonselective NSAIDs in an older Medicaid cohort.
BACKGROUND
Cyclooxygenase-2-selective inhibitors (coxibs) have been widely adopted, despite study findings suggesting that they are cost-effective only in certain populations.


OBJECTIVE
This study was conducted to identify factors that were associated with the selection of coxibs rather than nonselective NSAIDs in the period before the emergence of safety concerns in 2004.


METHODS
This was a retrospective cohort analysis of a 15% random sample of Kansas Medicaid beneficiaries aged >60 years that used inpatient, outpatient, and prescription claims data. Subjects were included if they received a prescription for a coxib or nonselective NSAID after a 6-month period without an anti-inflammatory prescription claim and if they underwent at least 90 days of follow-up after the initial prescription. Using 2 previously published models (Dominick et al and Shaya and Blume), we analyzed the impact of factors potentially associated with the preferential selection of a coxib, including age, sex, race, history of upper gastrointestinal disease, chronic or acute use, and recent anticoagulant or corticosteroid therapy.


RESULTS
Study subjects (N = 853) were predominantly female (78.8%) and white (80.4%), and had a mean age of 78 years; 65.1% were prescribed a coxib and 34.9% were prescribed a nonselective NSAID. In bivariate analyses, coxib users were more likely than nonselective NSAID users to be white (83.2% vs 75.3%, respectively; P < 0.05), to be prescribed chronic rather than acute therapy (81.8% vs 58.7%; P < 0.001), and to have a concomitant prescription for warfarin (11.2% vs 5.7%; P < 0.05). Multivariate analyses indicated significance for the same predictors of coxib use: chronic versus acute therapy (Dominick model: adjusted odds ratio [AOR] = 3.39; 95% CI, 2.43-4.74; Shaya model: AOR = 3.39; 95% CI, 2.43-4.74); concomitant anticoagulant therapy (Dominick model: AOR = 2.16; 95% CI, 1.18-3.97; Shaya model: AOR = 2.31; 95% CI, 0.28-0.83); and black race (Dominick model: AOR = 0.48; 95% CI, 0.28-0.83; Shaya model: AOR = 0.49; 95% CI, 0.28-0.84). The most commonly prescribed nonselective NSAIDs were ibuprofen (14.3% of all subjects) and naproxen (6.6% of all subjects); the most commonly prescribed coxibs were rofecoxib (36.5%) and celecoxib (28.5%).


CONCLUSIONS
In this study in an older population, coxibs constituted almost two thirds of all initial anti-inflammatory prescriptions. The prescription of a coxib was influenced by concomitant anticoagulant use and chronic use. Blacks were significantly more likely than whites to receive a nonselective NSAID. Although coxib use has been affected by the association with cardiovascular risk that emerged after the period of this study, rational drug selection and reduction of racial/ethnic disparities remain important targets for improved quality of care.
Shireman
Theresa I
TI
Department of Preventive Medicine and Public Health, University of Kansas School of Medicine, Kansas City, Kansas 66160, USA. tshireman@kumc.edu
Rigler
Sally K
SK
D000367:Age Factors; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage; D000925:Anticoagulants / Q000008:administration & dosage; D015331:Cohort Studies; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004363:Drug Utilization; D005260:Female; D006801:Humans; D007345:Insurance Claim Review; D008297:Male; D008484:Medicaid; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D044469:Racial Groups; D012189:Retrospective Studies; D012737:Sex Factors
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000925:Anticoagulants; D052246:Cyclooxygenase 2 Inhibitors