Venous thromboembolism in obese hormonal contraceptive users: a large national database study

This study aimed to assess the risk of venous thromboembolism (VTE) among obese and nonobese females aged 10 to 44 years prescribed hormonal therapy (HT) and compare VTE rates between different HT types in a large national database.

A retrospective cohort study was conducted using TriNETX data, which includes electronic health records and pharmaceutical claims from 81 million patients across 56 US tertiary care hospitals. Females prescribed HT between 2000 and 2022 were stratified by body mass index. VTE incidence was identified using International Classification of Diseases, Ninth/Tenth Revision, codes and anticoagulant prescriptions. Propensity score matching controlled for confounders.

Of 4,020,467 females, 34% (1,370,481) were obese. VTE incidence was higher in obese HT users (0.99%) than nonobese users (0.51%; P < .01). Obese users of levonorgestrel + ethinyl estradiol (EE) had a VTE rate of 0.55% vs 0.33% in nonobese users (P = .01, relative risk [RR] = 1.63). Similarly, obese users of norethindrone + EE (0.44% vs 0.24%; P < .01; RR = 1.8) and norgestimate + EE (0.44% vs 0.22%; P < .01; RR = 1.97) had higher VTE rates. No significant differences were found for progesterone-only HT users.

In this large study comparing rates of VTE among obese and nonobese females on HT, a significantly higher risk of VTE was observed among obese females using certain HTs, particularly EE with levonorgestrel, norethindrone, and norgestimate. These results highlight the importance of considering obesity as a key risk factor when prescribing HT, particularly for females with higher body mass index.