Eight RCTs were included in the review (18,607 women and 35,771 men; numbers taken from tables); six trials were placebo controlled (8,200 women and 27,991 men), one trial compared statin therapy with diet (5,356 women and 2,476 men), and one trial compared statin therapy with usual care (5,051 women and 5,304 men). Three trials scored 5 points for quality, four trials scored 4 points, and one trial scored 2 points. The average length of follow-up was 3.9 years (range 2.8 to 5.3 years).
Tests showed no evidence of publication bias.
There was no association between statin use and mortality for men (RR 0.93, 95% CI 0.83 to 1.04; I2=0%; five trials) or for women (RR 0.96, 95% CI 0.81 to 1.13; I2=34.2%; four trials) when compared with control groups. Sensitivity analyses did not significantly alter the results.
There was a lower risk of coronary heart disease events with statin therapy for men (RR 0.59, 95% CI 0.48 to 0.74; I2=89.1%; seven trials) when compared with control groups. For women there was some reduction, but this did not reach statistical significance (RR 0.89, 95% CI 0.79 to 1.00; I2=17.9%; six trials).
After the exclusion of one study (with a Jadad score of less than 3 points), a statistically significant reduction in risk of coronary heart disease events was found with statin therapy among women (RR 0.84, 95 %CI 0.73 to 0.97). All other results remained unchanged in sensitivity analyses.