This meta-analysis aims to examine the risk of stroke in healthy postmenopausal women during and after hormone therapy (HT).
Medline, The Cochrane Library, EMBASE, and Google Scholar were searched for randomized controlled trials involving healthy postmenopausal women who received HT and were followed up for at least 3 years after starting treatment. The primary outcome measures were stroke hazard ratio (HR) for the intervention phase, stroke HR for the postintervention phase, and overall stroke HR.
Four studies, involving 15,423 participants who received HT and 14,582 participants who received placebo, met the criteria for inclusion in the meta-analysis. The mean age of participants ranged from approximately 50 to 64 years. HT was given as conjugated equine estrogens in three studies and as 17β-estradiol in one study. The duration of HT ranged from 3.0 to 10.1 years. The length of follow-up after the start of HT ranged from 3.0 to 15.8 years. Meta-analysis revealed that the stroke HR during the intervention phase and the overall stroke HR were significantly increased among women who received HT (intervention phase: pooled HR, 1.32; 95% CI, 1.12-1.56; P = 0.001; overall: pooled HR, 1.15; 95% CI, 1.03-1.28; P = 0.017). The stroke HR during the postintervention phase was not increased among women who received HT (pooled HR, 1.00; 95% CI, 0.85-1.16; P = 0.958). Sensitivity analysis confirmed the reliability of the meta-analysis for both outcomes.
These findings suggest that HT may increase the risk of stroke during, but not after, HT in healthy postmenopausal women.