In a retrospective cohort study of women using contraceptives, the FDA reported that the norelgestromin/ethinyl estradiol (NGMN) transdermal patch (Ortho Evra), drospirenone/ethinyl estradiol pill (DRSP; Yaz) and the etonogestrel/estradiol vaginal ring (ETON; NuvaRing) put women at a higher risk for venous thromboembolism (VTEs) when compared with standard low-dose contraceptives.
The FDA used data from two medical care programs (both Kaiser Permanente) and two state Medicaid programs (Tennessee and Washington) to conduct a retrospective review of 835,826 women with 898,251 person-years of combined hormonal contraceptives (CHCs). During the study, staff evaluated the risk of thrombotic and thromboembolic events and all-cause CV mortality for three newer CHCs. The FDA compared three contraceptives—NGMN, ETON and DRSP—with four older CHCs with similar low estrogen levels.
All of the women enrolled in the study were between the ages of 10 and 55 and all had at least one prescription for a study CHC between Jan. 1, 2001, and Dec. 31, 2007.
The researchers reported incidence rates of acute MI, VTE and deep vein thrombosis (DVT), in addition to total CV mortality. Of the cohort, there were 189,210 person-years of exposure to DRSP, 67,865 person-years of exposure to NGMN, 23,910 person-years of exposure to ETON and 617,265 person-years of exposure to the comparator CHCs.
During the study period, 60 AMIs, 78 ischemic strokes and 625 VTEs were reported. Additionally, there were 41 CVD deaths and 267 total deaths during the exposure period. All newer drugs were found to be associated with a heightened risk of VTE compared with low-estrogen comparators; however, only DRSP was associated with a higher risk of both arterial thromboembolism and VTE.
When DRSP was taken for three months and between six to 12 months, the risk of VTE significantly increased. Additionally, it was reported that the NGMN patch was linked to a higher risk for VTE at 12 months. The risk of VTE was greater for younger patients (aged 10 to 34 years) taking the medication compared to older patients (aged 35 to 55 years).
“We conclude that the study results add to the small body of literature which shows that the NGMN transdermal patch is associated with higher risk of VTEs relative to standard CHC pills and provides another positive finding to the increasing body of evidence linking DRSP to increased risk of VTE relative to standard low-dose CHC pills,” the FDA wrote. “The finding of increased risk of VTE with the ETON vaginal ring relative to standard CHCs is new and raises concern but needs to be replicated in other studies.”