Dual blood thinners under prescribed after minor or warning stroke, especially in women

Despite evidence that starting two blood-thinning medications shortly after a minor stroke or a warning stroke (transient ischemic attack—TIA) may prevent a second—possibly more serious—clot-caused stroke within a few months, the treatment regimen is underused especially among women, according to preliminary research to be presented at the American Stroke Association's International Stroke Conference 2023. The meeting, to be held in person in Dallas and virtually Feb. 8-10, 2023, is a world premier meeting for researchers and clinicians dedicated to the science of stroke and brain health.

Blood thinners, such as aspirin and clopidogrel, prevent platelets from sticking together and forming blood clots. Prescribing two anti-platelet medications at the same time is known as dual antiplatelet therapy (DAPT). In recent trials, DAPT has been shown to reduce the short-term risk of another stroke in people with a recent minor stroke (mild, non-disabling symptoms) or with a TIA. As with most strokes, a TIA is caused by a clot temporarily blocking blood flow to the brain, however, TIA symptoms usually only last a few minutes and result in no permanent brain injury or physical disability.

"All stroke survivors, regardless of sex, should receive optimal proven medications for stroke prevention including DAPT when medically appropriate," said Jonathan Solomonow, M.D., lead author of the study and chief resident in neurology at the University of Maryland Medical Center in Baltimore.

To gauge how often DAPT was being prescribed when people with a minor stroke or TIA were discharged, the researchers reviewed the electronic health records of 2,953 adults admitted to one of the hospitals of the University of Maryland Stroke Clinical Network. The Maryland network includes nine stroke centers located in urban, suburban and rural hospitals serving a diverse population. All were treated for minor stroke or TIA between 2018 and 2021. None were taking blood thinning medication such as warfarin or apixaban before the stroke or TIA. The participants were average age 67 years; 42% were age 70 or older; 48% women, 37% Black adults and 60% white adults.

The analysis found:

• DAPT was underutilized across all hospitals reviewed, prescribed to just 40% of the overall patients.
• Men were more likely than women (43% vs. 37%, respectively) to be prescribed DAPT.
• The percentage of patients receiving DAPT did not differ significantly by race, age or whether the person was treated at a stroke center that delivers specialized stroke care.

"There are an increasing number of options available to prevent and reduce the risk of a recurrent stroke, including high blood pressure medications, statins to control cholesterol and dual blood thinners. Patients and their family members should inquire about the use of DAPT after a stroke or TIA to consider if DAPT may be beneficial," Solomonow said.

The gender gap noted in the study could not be explained by differences in insurance coverage or in anticipated side effects of the medications, Solomonow added.

"The gender gap was not entirely surprising because there is extensive literature indicating that women with cardiovascular disease tend to be undertreated. For example, some studies show that women with heart disease or stroke are not prescribed statins as frequently as men. In addition, women with atrial fibrillation receive ablation less often than men," Solomonow said. "Further research is needed to examine whether women are less likely to receive other proven therapies, such as statins for stroke prevention and anti-coagulation for atrial fibrillation."

The study analyzed data from a single health system in Maryland, so the findings need to be confirmed in other settings including hospitals that are not certified stroke centers.

"Identifying systemic inequities is essential to improving patient care across all demographics. It would be useful for other centers to explore whether sex differences are present in other parts of the U.S. or health care systems in other countries," Solomonow said.

Co-authors are Jamie R. Marks, Ph.D.; Karen L. Yarbrough, C.R.N.P.; Prachi Mehndiratta, M.B.B.S.; and Seemant Chaturvedi, M.D.