Hormonal Therapy May Be OK for Women Receiving Anticoagulants

Lara C. Pullen, PhD

January 06, 2016

Women who receive therapeutic anticoagulation and hormonal therapy are not an increased risk for recurrent venous thromboembolism (VTE) relative to women who receive therapeutic anticoagulation and no hormonal therapy, according to an analysis of the EINSTEIN deep vein thrombosis and pulmonary embolism cohorts published online December 23 in Blood.

The incidence of VTE was 3.7% per year "on" hormonal therapy and 4.7% per year "off" hormonal therapy, with an adjusted hazard ratio of 0.56 (95% confidence interval, 0.23 - 1.39), Ida Martinelli, MD, PhD, from Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda Ospedale Maggiore Policlinico in Milan, Italty, and colleagues report.

The upper limit of the 95% confidence interval around the hazard ratio excluded a clinically important difference in recurrent VTE, they explain.

The EINSTEIN deep vein thrombosis and pulmonary embolism studies used an open-label design. The women in the study were younger than 60 years (n = 1888) and were receiving anticoagulation with either rivaroxaban or enoxaparin/vitamin K antagonist.

The results remained true for pre- and postmenopausal women, as well as women taking estrogen-containing hormonal therapy and those taking progestin-only hormonal therapy. Women who received rivaroxaban did, however, have an increased risk for abnormal uterine bleeding when compared with women who received enoxaparin/vitamin K antagonist treatment.

The investigators were surprised to discover that women who used hormonal therapy had similar rates of abnormal uterine bleeding and uterine bleeding leading to blood transfusion as women who were not receiving hormonal therapy. The authors suggest that improved management of anemia may decrease the need for transfusion in women with uterine bleeding.

Meeting the Needs of Women

Premenopausal women who receive oral anticoagulant therapy require adequate contraceptive measures to prevent pregnancy and avoid serious toxic effects on the fetus.

Every woman should be evaluated to determine the unique risks and benefits of different forms of contraception, Daniela Carusi, MD, the director of general gynecology and surgical obstetrics at Brigham and Women's Hospital, Boston, Massachusetts, told Medscape Medical News.

Dr Carusi found the results from the study to be comforting and consistent with current medical practice.

"This is a practice that some providers had already attempted, after weighing theoretical risks and benefits. The study lends some data to the assumptions, and may open up some options for women on anticoagulation. I am not sure it's enough to change practice for all women — individual risks and benefits still need to be weighed," she explained.

In 2015, the World Health Organization published their revised medical eligibility criteria for contraception use. The 2015 revision states that, "Although evidence on the risk of venous thrombosis with the use of [progestogen-only contraceptives] is inconsistent, any small increased risk is substantially less than that with [combined oral contraceptives]. Limited evidence indicates that insertion of the [levonorgestrel-releasing intrauterine device] does not pose major bleeding risks in women on chronic anticoagulant therapy."

One coauthor reports grant support from Sanquin, grant support and fees paid to her institution from GlaxoSmithKline and Bristol-Myers Squibb/Pfizer, and fees paid to her institution from Bayer, Boehringer Ingelheim, and Daiichi Sankyo. Another coauthor reports grant support and personal fees from Bayer, Boehringer Ingelheim, Daiichi Sankyo, and Pfizer. Another coauthor reports personal fees from Bayer and Daiichi Sankyo. Another coauthor reports personal fees from Bayer. Another coauthor reports receiving personal fees from Bayer, Boehringer-Ingelheim, BMS, Daiichi, Johnson and Johnson, Mitsubishi Pharma, Pfizer, Portola, Sanofi, Schering Plough, and XO1. Another coauthor is an advisor to the UK Government Health Select Committee, the all-party working group on thrombosis, the Department of Health, and the National Health Service on the prevention of VTE and is also an advisor to Lifeblood: the thrombosis charity and is the founder of the European educational charity the Coalition to Prevent Venous Thromboembolism. Another coauthor has received grant support from BMS/Pfizer and honoraria from Bayer HealthCare Pharmaceuticals. Another coauthor reports personal fees from Bayer, Pfizer, Daiichi Sankyo, and Boehringer Ingelheim. Four authors are employees of Bayer HealthCare Pharmaceuticals. The other authors have disclosed no relevant financial relationships.

Blood. Published online December 23, 2015. Abstract


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