The effects of hormone replacement therapy on coronary heart disease in postmenopausal women: Systematic review and assessment of methods

Abstract

Hormone replacement therapy (HRT) was commonly prescribed to postmenopausal women to decrease the risk of coronary artery disease. Non-randomized studies have demonstrated up to 40% reduction in women using HRT. The first randomized trial to study this association failed to find the anticipated cardiac benefit. Since then, several trials addressing primary or secondary prevention of heart disease with HRT have failed to find any association. This thesis analyzed all available data on HRT and heart disease to identify factors contributing to the divergent results. We found that in non-randomized studies, current users of HRT had a decreased risk of heart disease while the summary statistic for RCTs failed to show any association. Measurement of exposure and socioeconomic status were important confounding variables. The strengths and limitations of study designs were discussed. A second component of the thesis was the modification of Newcastle Ottawa scale, a quality assessment tool for non-randomized studies.