Randomised controlled trials (RCTs) that compared statins with placebo for primary prevention of cardiovascular disease were eligible for inclusion. Studies were required to report sex-specific results and to have at least one year follow-up. Outcomes of interest were all-cause mortality, major cardiovascular disease events (fatal and non-fatal myocardial infarction, first revascularisation or cardiac surgery, unstable angina or any combination of these) and cancer.
All the eligible studies included both men and women; the proportion of women ranged from 15% to 69%. Only data relevant to women were included in the review. Mean age ranged from 58 to 64 years (where reported). Mean baseline low density lipoprotein cholesterol (LDL-C) ranged from about 127 to 160mg/dL. More than 99% of participants had no history of coronary heart disease. Lovastatin, pravastatin, atorvastatin, simvastatin and rosuvastatin were used at low to medium doses, combined with antihypertensives, diet, hormone replacement therapy and/or aspirin. Most primary studies reported various coronary heart disease events as a composite outcome. Outcomes reported in the review were all-cause mortality, coronary heart disease events (which included myocardial infarction, angina, stroke, revascularisation, congestive heart failure, cerebrovascular disease, symptomatic peripheral vascular disease and coronary heart disease mortality) and cancer. Median duration of follow-up ranged from 1.9 to 5.3 years. Most trials were multicentre and funded by pharmaceutical companies. Trials were conducted in USA, Europe, Japan and internationally (26 countries).
The authors did not state how many reviewers performed study selection.