TOPLINE:

Oral anticoagulant users had 6.1% incidence of abnormal uterine bleeding (AUB) compared to 3.0% in nonusers, with women under 50 experiencing higher rates at 19.7% vs 9.2%. Among all agents studied, rivaroxaban was associated with the highest risk for AUB at 8.6%.

METHODOLOGY:

• Researchers conducted a nested matched case-control study using MarketScan Research Databases (2008-2022), analyzing 276,911 anticoagulant users matched 1:5 to 1,384,555 nonusers.
• Analysis included women aged ≥ 18 years initiating oral anticoagulants (warfarin, apixaban, rivaroxaban, dabigatran, and edoxaban) for deep venous thrombosis, pulmonary embolism, or atrial fibrillation/flutter.
• The primary outcome measure was AUB within 1 year, and secondary outcomes included AUB-related hospitalizations, emergency department visits, and outpatient encounters.
• Investigators utilized conditional logistic regression models adjusted for matching factors and baseline clinical covariates to derive all estimates.

TAKEAWAY:

• Anticoagulant users had significantly higher odds of AUB than nonusers (adjusted odds ratio [aOR], 1.81; 95% CI, 1.69-1.93), with elevated risks for hospitalization (aOR, 62.32; 95% CI, 30.94-125.53) and emergency department visits (aOR, 5.78; 95% CI, 4.02-8.31).
• Women younger than 50 years had greater relative increase in AUB (AOR, 1.96; 95% CI, 1.79-2.14) than women aged ≥ 50 years (aOR, 1.63; 95% CI, 1.50-1.78).
• Rivaroxaban users experienced the highest AUB risk (aOR, 2.23; 95% CI, 2.08-2.39) compared to nonusers, followed by apixaban (AOR, 1.66; 95% CI, 1.54-1.79) and dabigatran (aOR, 1.54; 95% CI, 1.35-1.75) users.
• Among anticoagulant users aged ≥ 50 years, apixaban users had lower odds of AUB (aOR, 0.870; 95% CI, 0.869-0.872) than warfarin users, whereas rivaroxaban users (aOR, 1.215; 95% CI, 1.213-1.217) had higher odds.

IN PRACTICE:

“These data suggest that treatment with oral anticoagulants is associated with significantly increased risk of AUB. Although the risk of AUB is elevated in adult women of all ages, it was particularly higher in anticoagulant therapy users younger than 50 years of age,” the authors of the study wrote.

SOURCE:

The study was led by Lielle Yellin, Columbia University Vagelos College of Physicians and Surgeons in New York City. It was published online in Obstetrics & Gynecology.

LIMITATIONS:

According to the authors, the study relied on billing codes which likely underestimate milder or self-managed bleeding episodes. The 1-year follow-up window may have undercaptured delayed-onset or recurrent AUB events. Additionally, while researchers adjusted for measurable confounders, unmeasured factors might have influenced anticoagulant selection and AUB risk, indicating possible residual confounding. The researchers also noted that due to the rarity of AUB-related healthcare utilization events (< 5%), they could not estimate the association of these outcomes and anticoagulant use in some populations.

DISCLOSURES:

Yukio Suzuki disclosed receiving payment from Mitsui & Co. Jason Wright reported receiving royalties from UpToDate, honoraria from the American College of Obstetricians and Gynecologists, and research support from Merck. Xiao Xu received honoraria from the American Association of Gynecologic Laparoscopists. Elena Elkin reported receiving research support from Pfizer.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.