Abstract
A systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies was conducted to assess the association between menopausal hormone therapy and cardiovascular disease. The PubMed and EMBASE databases were searched for articles published from 2000 to 2019, using review methods based on a previous Cochrane review. Quality assessment of RCTs and observational studies was conducted using the Jadad scale and the Newcastle-Ottawa Scale, respectively. A total of 26 RCTs and 47 observational studies were identified. The study populations in the RCTs were older and had more underlying diseases than those in the observational studies. Increased risks of venous thromboembolism [summary estimate (SE), 95% confidence interval (CI): RCTs, 1.70, 1.33-2.16; observational studies, 1.32, 1.13-1.54] were consistently identified in both study types, whereas an increased risk of stroke in RCTs (SE: 1.14, 95% CI: 1.04-1.25) and a decreased risk of myocardial infarction in observational studies (SE: 0.79, 95% CI: 0.75-0.84) were observed. Differential clinical effects depending on timing of initiation, underlying disease, regimen type, and route of administration were identified through subgroup analyses. These findings suggest that underlying disease and timing of initiation should be carefully considered before starting therapy in postmenopausal women.