Six RCTs (33,500 participants) were included. The mean follow-up ranged from 2 to 4.8 years.
Generation of allocation and allocation concealment were adequate in most studies. All studies were double-blinded, although blinding of the outcome assessment and data analyses was unclear in some studies. All studies used an intention-to-treat analysis.
The percentage of people on the study drug at 3 years ranged from 71 to 81%.
Tests showed no evidence of heterogeneity between the studies and no evidence of publication bias.
ACEI treatment resulted in a mean decrease of 3.9 mmHg in SBP and 1.8 mmHg DBP (5 trials), and a decrease in new onset diabetes (RR 0.76, 95% CI: 0.60, 0.95, p=0.02; 2 trials).
Compared with placebo, ACEI treatment was associated with a reduction in cardiovascular mortality (RR 0.83, 95% CI: 0.72, 0.96, p=0.01), nonfatal MI (RR 0.84, 95% CI: 0.75, 0.94, p=0.003), all-cause mortality (RR 0.87, 95% CI: 0.81, 0.94, p=0.0003) and revascularisation (RR 0.93, 95% CI: 0.87, 1.00, p=0.04). The NNT to prevent one of any of these outcomes was 100.
The results of the sensitivity analyses were similar to those of the main analyses, but with wider CIs. Details were given in the paper.
In subgroup analyses there was no evidence of any significant difference in outcomes between subgroups. Details were given in the paper.