Menopausal hormone therapies and the risk of stroke varies with route of administration

Courtesy: menopausemoxie.com

Route of menopausal hormone therapy plays a very important role in increasing or decreasing the risk of stroke in postmenopausal women reports the results of large Danish national historical study. The study was originally  published in June 2017 in Journal Stroke.

Randomized trials have shown an increased risk of stroke and the study was not completed because of higher risk faced by study participants.

This large epidemiological study included nearly all women aged 51 to 70 years living in Denmark and the cohort was recruited by linking 5 Danish registries, that provided data about hormone therapy exposure and stroke diagnoses (ischemic/hemorrhagic/subarachnoid hemorrhage).

Of, nearly a million women included in the study, 36% used hormone therapy. 2% women (20 199) suffered a stroke.

Current users of hormones were 16 % at increased risk of stroke as compared to never users (RR) 1.16 (95% CI 1.12–1.22), but the risk of hemorrhagic stroke decreased RR: 0.80 (95% CI, 0.70–0.91).

Users of oral continuous, cyclic combined estrogen/progestin, and estrogen only were at 29%, 11% and 18% more at risk respectively for all strokes as compared to never users. The increased risk was because of ischemic stroke, but not hemorrhagic stroke.

Transdermal HT is safer and does not lead to increased risk of stroke. Unopposed transdermal estrogen therapy had a protective effect, it decreases the risk by 18% (RR 0.82; 95% CI 0.69-0.98).

Vaginal HT was also protective and decreased the risk of stroke by 35% (RR 0.65; 95% CI 0.59-0.70).

Tibolone use increased the stroke risk by nearly 30%, including haemorrhagic.

The authors concluded that, “we found an increased risk of stroke, based on ischemic stroke, with oral hormone therapies that was comparable to findings from randomized studies. We found no risk of stroke with transdermal application and a reduced risk with vaginal estrogen.”