Venous Thromboembolic Risk of Estradiol Valerate-Dienogest Compared with Ethinyl Estradiol-Levonorgestrel Combined Oral Contraceptives.

ABSTRACT

This pooled analysis compared the risk of venous thromboembolism (VTE) associated with combined oral contraceptives (COCs) containing estradiol (E2) valerate-dienogest with those containing ethinyl E2-levonorgestrel. Data were retrieved from two large, prospective, observational cohort studies. Propensity score subclassification was applied to balance baseline parameters between the COC user cohorts. Crude and adjusted hazard ratios (HRs) were calculated based on the extended Cox model. The pooled data set included 11,616 E2 valerate-dienogest users and 18,681 ethinyl E2-levonorgestrel users, contributing 17,932 and 29,140 women-years of observation, respectively. A significantly decreased VTE risk in E2 valerate-dienogest COCs compared with ethinyl E2-levonorgestrel COCs was observed (propensity score-stratified HR 0.46, 95% CI, 0.22-0.98). This pooled analysis expands data from a previous postauthorization safety study and provides valuable real-world safety information on the relative safety of current COCs.