Efficacy and safety of LDL-lowering therapy among men and women: meta-analysis of individual data from 174,000 participants in 27 randomised trials

Background: Whether statin therapy is as effective in women as in men is debated, especially for primary prevention. We undertook a meta-analysis of statin trials in the Cholesterol Treatment Trialists' (CTT) Collaboration database to compare the effects of statin therapy between women and men.

Methods: We performed meta-analyses on data from 22 trials of statin therapy versus control (n=134,537) and five trials of more-intensive versus less-intensive statin therapy (n=39,612). Effects on major vascular events, major coronary events, stroke, coronary revascularisation and mortality were weighted per 1.0 mmol/L reduction in LDL cholesterol and effects in men and women compared with a Cox model that adjusted for non-sex differences. For subgroup analyses, we used 99% CIs to make allowance for the multiplicity of comparisons.

Findings: 46,675 (27%) of 174,149 randomly assigned participants were women. Allocation to a statin had similar absolute effects on 1 year lipid concentrations in both men and women (LDL cholesterol reduced by about 1.1 mmol/L in statin vs control trials and roughly 0.5 mmol/L for more-intensive vs less-intensive therapy). Women were generally at lower cardiovascular risk than were men in these trials. The proportional reductions per 1.0 mmol/L reduction in LDL cholesterol in major vascular events were similar overall for women (rate ratio [RR] 0.84, 99% CI 0.78-0.91) and men (RR 0.78, 99% CI 0.75-0.81, adjusted p value for heterogeneity by sex=0.33) and also for those women and men at less than 10% predicted 5 year absolute cardiovascular risk (adjusted heterogeneity p=0.11). Likewise, the proportional reductions in major coronary events, coronary revascularisation, and stroke did not differ significantly by sex. No adverse effect on rates of cancer incidence or non-cardiovascular mortality was noted for either sex. These net benefits translated into all-cause mortality reductions with statin therapy for both women (RR 0.91, 99% CI 0.84-0.99) and men (RR 0.90, 99% CI 0.86-0.95; adjusted heterogeneity p=0.43).

Interpretation: In men and women at an equivalent risk of cardiovascular disease, statin therapy is of similar effectiveness for the prevention of major vascular events.

Funding: UK Medical Research Council, British Heart Foundation, Australian National Health and Medical Research Council, European Community Biomed Program.