Seven RCTs (n= 33,960) were included in the meta-analysis. The sample size varied from 460 to 12,218. All studies were scored 5 using the measures of quality assessment. The mean follow-up duration of included studies was 4.4 years (range 2 to 5 years).
When the studies were pooled, ACE inhibitors were significantly associated with a reduction in all-cause mortality compared with control group (OR 0.86, 95% confidence interval, CI: 0.79, 0.93, p<0.001; seven RCTs), a reduction in cardiovascular death (OR: 0.81, 95% CI: 0.73, 0.90, p<0.001; seven RCTs), a reduction in MI (OR 0.82, 95% CI: 0.75, 0.89, p<0.001; seven RCTs), and a reduction in the occurrence of stroke (OR 0.77, 95% CI: 0.66, 0.88, p<0.001; seven RCTs).
Results for the secondary outcomes of the reduction of hospitalisation because of heart failure, myocardial revascularisation and new onset of diabetes mellitus were also reported.
There was no evidence of statistically significant heterogeneity for the outcome measures. Sensitivity analyses did not materially affect the results. No evidence of publication bias was found according to the visual scanning of funnel plots and the test of Begg and Mazumdar.