According to a study in British Medical Journal (BMJ), the risk of women suffering a stroke in comparison with men is moderately higher. The study suggests that doctors should consider a patient’s gender when deciding on anti-clotting treatments.

Even though various studies have indicated that women with atrial fibrillation (AF), i.e. a stoke that occurred due to an insufficient blood supply to the brain, have a higher risk of ischemic stroke than men, other studies in contrast failed to confirm this finding. Doctors need to be aware that gender issue is an important factor when making decisions about anti-clotting treatment regardless of whether few or other risk factors of stroke exist.

Researchers from the Swedish Karolinska Institute and England’s Birmingham University examined whether women with atrial fibrillation have a higher risk of stroke than men, assessing more than 100,000 patients diagnosed with AF in all Swedish hospitals or hospital affiliated outpatient clinics. The team followed the participants for an average duration of 1.2 years, i.e. a total of 139,504 years at risk.

During the study period 7,221 patients suffered a thromboembolic stroke due to clots. Ischemic strokes proved to be more frequent with 4,264 strokes during 69,005 years at risk in women, which is an annual stroke rate of 6.2% and 2,957 strokes during 70,594 years at risk in men, which translates to a yearly stroke risk of 4.2%.

The team observed that the stroke risk of women was still 18% higher than that of men after adjusting the results for 35 factors, which could have impacted the findings. However, the absolute annual rates of stroke risk for both sexes proved to be relatively low, i.e. 1.9% for women between the ages of 65 to 74 years and for men even less.

The team also noted that the risk for women below the age of 65 with no other risk factors aside from AF was not higher than that of men. They observed no statistically important difference in the risk of women suffering a stroke to men, with 31 strokes in women (4,626 at risk years) compared with 53 strokes in men (11,677 at risk years).
The researchers conclude that the risk of stroke in women with AF is moderately higher than that of men and doctors should consider this factor with regard to making decisions about anti-clotting treatment. They continue saying: “In borderline situations, in which a decision about whether to give anticoagulation treatment weighs in the balance, we suggest that female sex should probably tip the scale towards initiating treatment,” and add that no anticoagulation therapy is required for women under the age of 65 years with a low risk of stroke and no other risk factors.

Professor Eva Prescott from Denmark’s University Hospital in Bispebjerg comments in a linked editorial that the findings of this and other studies are reassuring for doctors, regardless of some inherent limitations. Prescott writes:

“The registry data confirm overall that women are at higher risk of stroke than men, but when differences in age and risk factor profile are taken into account the excess risk is low. More importantly, the absolute risk in younger women with no other risk factors is low and does not merit treatment with oral anticoagulants.”

Written By Petra Rattue