Even in the DOAC Era, Women Less Likely Than Men to Receive Anticoagulation for A-fib

SAN FRANCISCO, CA—As direct oral anticoagulants (DOACs) have increasingly displaced warfarin for stroke prevention in patients with A-fib, sex disparities in treatment have persisted, new data indicate.

Between 2008 and 2014, women were less likely than men to be prescribed any oral anticoagulation for newly diagnosed A-fib (48% vs 53%), a gap that was seen both for warfarin (38% vs 41%) and DOACs (12% vs 15%; P < 0.0001 for all comparisons), Mintu Turakhia, MD (Stanford University and VA Palo Alto Health Care System, CA), reported at the Heart Rhythm Society 2019 Scientific Sessions here last week.

In a subset of patients deemed to be eligible for oral anticoagulation, prescription rates were higher overall but the sex difference remained.

Turakhia said there are several possible explanations for that observation, which is consistent with prior data, such as those from the PINNACLE Registry. It could be, he said, that physicians perceive women to have a lower stroke risk and higher bleeding risk; there are differences between men and women in terms of treatment preferences; issues like frailty are coming into play; or there are sex differences in terms of the types of physicians who are seen, which could affect the likelihood of receiving anticoagulation.

It is also possible that issues around patient-provider gender concordance are involved, because studies of other types of drugs have shown that when patients and physicians are of the same sex, adherence to guideline recommendations is greater, he added, pointing out that the vast majority of cardiologists—particularly electrophysiologists—are men.

Commenting for TCTMD, Cara Pellegrini, MD (University of California, San Francisco), said the gap in use of oral anticoagulation between women and men is important because women tend to have worse outcomes related to A-fib, including a higher risk of stroke, as was confirmed in this study.

“One could imagine that perhaps some of the obstacles with warfarin might not be present with DOAC use—specifically, there are less drug-drug interactions, it requires fewer patient-provider interactions, it seems to have a lower threshold for initiation and continuation,” Pellegrini said. “So it seemed to be a relevant question as to whether this same pattern [of fewer prescriptions in women] has persisted, and my take-home from Dr. Turakhia’s presentation was that it does seem like this is still the case.”

Turakhia and colleagues turned to Truven Health MarketScan databases to examine whether the sex disparity remained even as DOACs were rapidly being incorporated into practice. Their analysis included 358,649 patients (43% women) who had newly diagnosed A-fib or atrial flutter between 2008 and 2014 and who received any outpatient prescription within 90 days of the initial diagnosis.

Patient characteristics differed between women and men at baseline. On average, women were older (69 vs 64 years) and had a higher CHA2DS2-VASc score (3.4 vs 2.1) and HAS-BLED score (1.8 vs 1.6). They were more likely than men to have hypertension, prior stroke/TIA, and anemia, but less likely to have diabetes and prior MI.

Women were also less likely to receive oral anticoagulation, even among the subset of patients considered eligible based on having a CHA2DS2-VASc score of at least 2 and a HAS-BLED score no higher than 3.

Overall, women had higher risks of ischemic stroke (HR 1.27; 95% CI 1.21-1.32) and all-cause hospitalization (HR 1.06; 95% CI 1.05-1.07), which were partly mediated by the lesser use of oral anticoagulation, Turakhia reported. But women also had a lower risk of intracranial hemorrhage (HR 0.91; 95% CI 0.83-0.99), also mediated in part by the differential use of anticoagulation. “This indicates that, in fact, there is a real risk of intracranial hemorrhage, and in women more than men it’s mediated by anticoagulation,” Turakhia said.

Asked how all of this plays into considerations around how clinicians should discuss oral anticoagulation with women, Pellegrini noted that subgroup analyses of all the pivotal DOAC trials have indicated that there is a net benefit from taking DOACs in both women and men.

“In general, for my female patients, if they meet appropriate criteria for anticoagulation I would still encourage that,” she said. “Obviously, it’s important to have an informed conversation about the pros and cons, but at the end of the day I think the benefit still outweighs the harm.”

As for how to address the lower prescription rates among women, Pellegrini said analyses like this one are a good first step to highlight the problem. Then the aim is to explore the reasons for the disparity so efforts can be made to address it, she said.

“Some of the things that I think we [at various societies]—or as individual providers—should be doing is trying to get the word out and educate patients and other providers that women who have A-fib also benefit from anticoagulation on the whole and should be considered just the same as men on the basis of their CHA2DS2-VASc or other risk-based score for anticoagulation therapy,” Pellegrini said. “So I think it should be an educational process.”

She added that efforts to increase the number of women in cardiology in general—and in electrophysiology specifically—would be expected to have benefits.