Describe the patterns of use and safety of Hormone replacement therapy (HRT) in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) women.

CADASIL commonly presents with recurrent stroke, migraine, and cognitive impairment. HRT is used for menopausal symptoms relief but may increase stroke risk and affect migraines, and its safety in postmenopausal CADASIL women remains uncertain.

We conducted a retrospective longitudinal study across the Mayo Clinic health system in genetically or histopathologically confirmed CADASIL women aged ≥45 years. Clinical outcomes assessed were incident stroke, dementia and death. Baseline characteristics were compared. Kaplan-Meier and Log-rank test were used to estimate and compare survival rates.

Of the 45 patients meeting inclusion criteria, 11 (24.4%) received HRT and 34 (75.6%) did not. There was no significant age difference between the HRT and non-HRT groups (60.7 ± 8.8 vs. 61.1 ± 9.5; P ≥0.05). A history of migraines was more common in the HRT group (90.9% vs. 52.9%; P = 0.033). Among the HRT group, 72.7% were using estradiol; 18.2%, conjugated estrogen; and 9.1%, dehydroepiandrosterone. The most common route of administration was transvaginal (63.6%) followed by the transdermal (27.3%). The median survival time for stroke or death in HRT and non-HRT group was 11.8 and 13.8 years (P ≥0.05), respectively. For composite stroke, death or dementia, the median survival time for non-HRT group and HRT group are 8.3 and 6.8 years (P ≥0.05), respectively.

About one fourth of women over 45 years received some form of HRT. Migraine status did not appear to influence the decision to treat. In our small study HRT did not significantly increase risk of stroke, dementia, or death, but larger studies would be required to exclude a clinically significant difference in risk.