Glossary · Risk

Stroke risk and HRT

Definition: Stroke risk on HRT depends heavily on age and route. Oral estrogen modestly raises ischemic stroke risk in older women starting HRT after age 60; transdermal estrogen at standard doses does not significantly raise stroke risk in observational studies. The timing hypothesis applies to stroke as it does to other cardiovascular outcomes.

Detailed definition

The relationship between HRT and stroke is age- and route-dependent. The WHI showed an increased ischemic stroke risk with oral CEE in women aged 50–79 (predominantly older), with the absolute increase approximately 8 events per 10,000 woman-years. Subsequent observational studies and meta-analyses have shown that transdermal estradiol at standard menopause doses does not significantly raise stroke risk, while higher oral estrogen doses (≥0.625 mg CEE or equivalent) do. The biological basis is similar to VTE: oral estrogen induces hepatic prothrombotic and inflammatory changes that transdermal estrogen avoids. Within the timing hypothesis framework, women starting HRT before 60 with transdermal estradiol have a favorable cardiovascular risk profile overall, with stroke risk neither substantially increased nor decreased.

Why it matters in menopause

Stroke risk is part of the safety calculus for HRT, particularly for women over 60 considering initiation or for women with hypertension, diabetes, or atrial fibrillation. ClearedRx considers cardiovascular risk factors at intake and prefers transdermal in any patient with elevated stroke risk.

Sources

External references: Wikipedia.

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