Twelve RCTs with a total of 14,219 participants were included.
All-cause mortality was reduced with treatment by 12% (odds ratio, OR 0.88, 95% confidence interval, CI: 0.79, 0.97); the incidence of all CHD events was reduced by 20% (OR 0.80, 95% CI: 0.70, 0.92); the incidence of all stroke events was reduced by 36% (OR 0.64, 95% CI: 0.55, 0.73).
Numbers-needed-to-treat (NNTs) standardised to a 5-year follow-up period were also calculated: the standardised NNT for all stroke events was 22 (95% CI: 21, 35); for people under 65, the NNT was 113 (95% CI: 92, 1391); and the standardised NNT for all CHD events was 45 (95% CI: 36, 137).
The effect of publication bias was also estimated: using Rosenthal's method (see Other Publications of Related Interest no.2), 84 studies with a null result would be required to nullify the results of the review.