Objective: This meta-analysis aims to examine the risk of stroke in healthy postmenopausal women during and after hormone therapy (HT).
Methods: 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.
Results: 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.
Conclusions: These findings suggest that HT may increase the risk of stroke during, but not after, HT in healthy postmenopausal women.