Prediction of Venous Thromboembolism Risk Associated with Combined Oral Contraceptives: an Exploratory Model

Introduction and aims of the study: Combined oral contraceptives (COCs) containing ethinylestradiol (EE) increase venous thromboembolism (VTE) risk compared to non-users. COCs with estradiol (E2) have been introduced to lower this risk. Activated protein C resistance (APC-R), a dysregulation of hemostasis, is recognized as a risk factor for VTE in COC users. The endogenous thrombin potential (ETP)-based APC-R assay is the most suitable assessment of COC-induced coagulation changes. We aimed to model ETP-based APC-R outcomes in users of various COCs and non-users and assessed the model's correlation with VTE risks observed in epidemiological studies.