Study objective: To compare rates of stroke and acute myocardial infarction in users of the Ortho EVRA contraceptive patch with these rates in users of norgestimate-containing oral contraceptives (OCs) with 35 microg of ethinyl estradiol.
Design: Retrospective, population-based, epidemiologic study.
Data source: PharMetrics database.
Subjects: Females aged 15-45 years in the PharMetrics database who had filled at least one prescription for the Ortho EVRA contraceptive patch or a norgestimate OC between April 1, 2002, and March 31, 2005.
Measurements and main results: Incidence rates and 95% confidence intervals (CI) were estimated for the outcomes of ischemic stroke and acute myocardial infarction by exposure. Crude incidence rates of ischemic stroke among users of the patch and users of norgestimate OCs were 13.6/100,000 woman-years (95% CI 5.9-26.8) and 11.3/100,000 woman-years (95% CI 5.4-20.8), respectively. The crude incidence rate of acute myocardial infarction was 1.7/100,000 woman-years (95% CI 0.04-9.5) in current patch users and 7.9/100,000 woman-years (95% CI 3.2-16.3) in current users of norgestimate OCs. Incidence rate ratios (IRRs) were estimated for the outcomes by comparing data for users of the patch and users of a norgestimate OC. The IRR for stroke was 1.2 (95% CI 0.41-3.4) and for acute myocardial infarction was 0.2 (95% CI 0.004-1.7).
Conclusion: Ischemic stroke and acute myocardial infarction are rare among young women who use hormonal contraceptives, and the current data provide no suggestion of an increased risk of either ischemic stroke or acute myocardial infarction in users of the Ortho EVRA contraceptive patch compared with users of norgestimate OCs.