LOS ANGELES — Women on hormone replacement therapy (HRT) who experience an increase in migraine severity of one grade or more are at increased risk for ischemic stroke, according to study results presented here at the 2016 International Stroke Conference.
“We found that women who are currently taking HRT and have had a worsening severity of migraines have a 30% increased risk of having strokes, as compared to women who have worsening migraines but are not currently on HRT,” Haseeb A. Rahman, MD, lead author from the Zeenat Qureshi Stroke Institute in Minneapolis, told Neurology Advisor.
According to Dr Rahman, there is a large number of post-menopausal women on HRT, many of whom with a history of migraines, and women can develop more severe migraines while taking HRT.
“We wanted to investigate if a worsening of migraines while taking HRT increases the risk of stroke in these women,” he said. “To our knowledge, a correlation between worsening severity of migraines while taking HRT and increased stroke risk had never been studied before.”
Although previous studies had addressed the relationship between HRT and migraines as risk factors for stroke, Dr Rahman noted that they had sometimes come to differing conclusions. “There are still certain ‘grey areas’ in our understanding of the correlation of HRT and migraines as stroke risk factors,” he said.
For the current study, Dr Rahman and colleagues culled data for 82,208 women who were aged 50 to 79 years and were enrolled in the observational arm of the Women’s Health Initiative study. Researchers defined HRT as unopposed estrogen and/or estrogen plus progesterone, and examined the risk for ischemic stroke among women with migraines who were receiving HRT or who had previously or never received HRT.
Patients were divided into two groups: those who had an increase in migraine severity of one grade or more at 3 years, and those who experienced no change or a decrease in migraine severity at that same time point. Researchers compared the relative risk of developing ischemic stroke among patients who were currently on HRT with those who were either previously on HRT or who had never received HRT.
Overall, 45.8% of patients were on HRT and 54.2% were either past users or had never used HRT therapy.
Results indicated that 20.6% of patients who were currently on HRT demonstrated an increase in migraine severity compared with 18.7% of those previously on HRT and 17.3% of those never on HRT (P<.0001).
Compared with women who were current users of HRT and had experienced no change or a decrease in migraine severity, those who never or only in the past used HRT had a decreased odds ratio (OR) for ischemic stroke (0.91 vs. 1.1; P<.0001). This discrepancy in ischemic stroke likelihood was also observed when researchers compared patients who had never or only in the past used HRT (OR=0.81) with those who were current HRT users and had experienced an increase in migraine severity (OR=1.3; P<.0001).
As a result of the findings, Dr Rahman said neurologists should keep a close watch on migraines in post-menopausal women taking HRT.
“Aside from addressing the migraines as they worsen, it would be helpful to keep in mind a potential increase in stroke risk that may be related to this,” he said. “It is important to work in collaboration with the prescribing physician, who is often a primary care physician or gynecologist, to address the potential risks and benefits of placing a patient on HRT, or continuing them on it once started. It is also necessary to identify and improve other stroke risk factors as best as possible.”
For more coverage of ISC 2016, go here.
Rahman HA, Malik A, Saeed O, et al. Abstract WMP 57. Worsening Migraines in Current Hormone Replacement Therapy Users Predicts Higher Risk of Stroke. Presented at: International Stroke Conference; Feb. 16-19, 2016; Los Angeles.