This article is more than 5 years old. Information may no longer be current.
Hormone therapy appears safe for women on anticoagulants
Click Here to Manage Email Alerts
Hormonal therapy did not appear associated with an increased risk for recurrent venous thromboembolism or uterine bleeding among women on therapeutic anticoagulation, according to study results published in Blood.
However, the association between the new direct oral anticoagulant rivaroxaban (Xarelto, Janssen) and abnormal uterine bleeding requires further study, results showed.
Due to the potential for fetal complications, women receiving vitamin K antagonists need adequate contraception. However, WHO guidelines deem estrogen-containing contraceptives to be an “unacceptable health risk” for women receiving anticoagulants, due to a perceived increased risk for recurrent VTE, according to study background.
“While it has been common practice among health care providers to avoid prescribing hormone therapy and anticoagulants at the same time, there has been no evidence to support this decision,” Ida Martinelli, MD, PhD, of the A. Bianchi Bonomi Hemophilia and Thrombosis Center in Milan, said in a press release. “We conducted this study to address the fear felt by both the physician and patient when making the decision to stop or continue hormone therapy in this setting.”
Martinelli and colleagues compared the incidence rates of recurrent VTE and abnormal uterine bleeding using data from the EINSTEIN DVT and PE studies, which evaluated the safety and efficacy of rivaroxaban and the current standard of care, enoxaparin followed by vitamin K antagonists.
The analysis included data from 1,888 women aged younger than 60 years (mean age, 41.3 years) who received rivaroxaban (n = 925) or enoxaparin (n = 963) anticoagulation therapy with or without concomitant hormonal therapy.
Researchers computed incidence-density percentages per year, comparing years “on” and “off” estrogen-containing or progestin-only hormone therapies.
Seven hundred five women (37.3%) received hormone therapy at the time of their deep vein thrombosis or pulmonary embolism diagnosis, 303 of whom had stopped all hormonal therapy at time of randomization. Thus, 402 of these women used hormonal therapy at some time during the study period.
Seventy-three women (6.2%) who were not on hormone therapy at the time of their diagnosis initiated hormone therapy during the analysis period.
Thus, 475 total women used hormone therapy during the study period. These included estrogen-only pills, combined estrogen-progestogen contraceptives, and progestin-only contraceptives.
Overall, seven recurrent VTE events occurred in women using hormone therapy, whereas 38 events occurred during a period when women were not using hormone therapy.
Based on these data, the incidence–density rates were 3.7% per year with hormonal therapy and 4.7% per year without hormonal therapy.
The incidence–density rates of VTE were 3.7% for estrogen-containing therapies and 3.8% progestin-only forms of hormone therapy.
Thirty-seven abnormal uterine bleeding events occurred among women using hormone therapy (estrogen, n = 28; progestin, n = 9), whereas 148 events occurred among women not on hormone therapy (adjusted HR = 1.02; 95% CI, 0.66-1.57).
Women using rivaroxaban experienced abnormal uterine bleeding episodes more frequently than women on enoxaparin (HR = 2.13; 95% CI, 1.57-2.89).
The researchers acknowledged limitations of their analysis. Because the studies from which Martinelli and colleagues culled their patient data were both open-label, the potential for bias exists. Further, their analyses were not prespecified in the protocol or statistical analysis plans of the studies.
“For the first time, we demonstrate that women suffering from blood clots can safely take hormone-containing contraceptives or hormone replacement therapy with anticoagulants, providing women the freedom to choose the method of birth control and other hormone-containing medications they prefer,” Martinelli said. “While further investigation is needed to evaluate the inconvenience of abnormal uterine bleeding with rivaroxaban and the other direct oral anticoagulants, these results dispel former misconceptions and should allow clinicians to confidently treat their patients who take blood thinners and hormones concurrently.” – by Cameron Kelsall
Disclosure: Martinelli reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures.
Click Here to Manage Email Alerts