Coronary heart disease outcomes among chronic opioid and cyclooxygenase-2 users compared with a general population cohort

Background We estimated the incidence of myocardial infarction (MI) and coronary revascularization (CR) among users of chronic opioid therapy (COT) and compared risks across categories of morphine-equivalent doses of COT and comparator cohorts. Methods We conducted a retrospective claims-based study using de-identified data from a commercially insured population. A cohort of 148 657 adult users of COT, a matched cohort of the general population, and three cohorts of users of chronic cyclooxygenase-2 (COX-2) inhibitor therapy totaling 122 810 were identified. Incidence rates and incidence rate ratios (IRRs) of MI and MI/CR were estimated. Results Adjusted IRRs for MI ranged from 1.21 (95% confidence interval [95%CI], 1.02-1.45) among those receiving low COT doses to 1.89 (95%CI, 1.54-2.33) among those receiving high doses compared with those receiving very low doses, averaging < 15 mg/day. Similar patterns were shown for MI/CR. IRRs standardized to the age-sex distribution of the general cohort and adjusted for coronary heart disease risk factors showed 2.7 times the rate of MI and 2.4 times the rate of MI/CR in the COT cohort compared with the general population. Using the same analysis, COX-2 users had 1.7-1.9 times the rate of MI and MI/CR compared with the general cohort. Conclusions Chronic analgesic use with either COT or COX-2 was associated with an increased risk of cardiovascular outcomes. These findings suggest either a selection of high-risk patients to chronic analgesic treatment, coupled with unmeasured or residual confounding, or a potential cardiovascular effect of these medications. Further research is warranted to evaluate causes for this association. Copyright (C) 2011 John Wiley & Sons, Ltd.