Sex Differences in the Use of Oral Anticoagulants for Atrial Fibrillation: A Report From the National Cardiovascular Data Registry (NCDR®) PINNACLE Registry.

BACKGROUND: Despite higher thromboembolism risk, women with atrial fibrillation have lower oral anticoagulation (OAC) use compared to men. The influence of the CHA2DS2-VASc score or the introduction of non-vitamin K OACs on this relationship is not known. METHODS AND RESULTS: Using the PINNACLE National Cardiovascular Data Registry from 2008 to 2014, we compared the association of sex with OAC use (warfarin or non-vitamin K OACs) overall and by CHA2DS2-VASc score and examined temporal trends in OAC use by sex. Multivariable regression models assessed the association between sex and OAC use in those with CHA2DS2-VASc scores ≥2. Temporal analyses assessed changes in OAC use by sex over time. Of the 691 906 atrial fibrillation patients, 48.5% were women. Women were significantly less likely than men to use any OAC overall (56.7% versus 61.3%; P<0.001) and at all levels of CHA2DS2-VASc score (adjusted risk ratio 9% to 33% lower, all P<0.001). Compared to other thromboembolic risk factors, female sex was associated with lower use of OAC (risk ratio 0.90, 95%CI 0.90-0.91). Over time, non-vitamin K OAC use increased at a slightly higher rate in women (56.2% increase per year, 95%CI 54.6% to 57.9%) compared to men (53.6% increase per year, 95%CI 52.0% to 55.2%), yet women remained less likely to receive any OAC at all time points (P<0.001). CONCLUSIONS: Among patients with atrial fibrillation, women were significantly less likely to receive OAC at all levels of the CHA2DS2-VASc score. Despite increasing non-vitamin K OAC use, women had persistently lower rates of OAC use compared to men over time.