Hormone replacement therapy and myocardial infarction and stroke in postmenopausal Korean women.

Objective: This study aimed to investigate the association of hormone replacement therapy (HRT) use, type, duration and age of commencement with myocardial infarction (MI) and stroke in postmenopausal Korean women.

Methods: This nested case-control study used data from the National Health Insurance Service database to analyze 2017 data from women aged ≥50 years and diagnosed with natural menopause between 2004 and 2007. Among 356,160 eligible women, 36,446 used HRT for ≥1 year and 319,714 did not (controls). These two groups were matched 1:1 for statistical analysis. Type and duration were categorized into three categories.

Results: Women who started estrogen-progestogen therapy (EPT) or estrogen therapy (ET) in their 50s, or EPT or tibolone in their ≥60s exhibited a lower stroke risk than controls. MI risk was lower among women who used tibolone - regardless of duration - or EPT or ET for 1-3 years than among controls. Stroke risk was lower with tibolone use for ≥5 years or with EPT or ET use for 1-3 years or ≥5 years than non-users.

Conclusion: Our study may support the beneficial effect of HRT by showing that Korean postmenopausal women who used HRT at a relatively younger and healthier age had a relative benefit for MI and stroke.