There were 25 trials in the review, with 152,290 participants. The trials were at a low risk of bias, although some did not use blinding. Follow-up times ranged from two to 8.4 years.
ACE inhibitors, compared with placebo, reduced the risk of major cardiovascular events (HR 0.81, 95% CI 0.73 to 0.90). Calcium antagonists were also more effective than placebo (HR 0.72, 95% CI 0.58 to 0.89). For each 5mmHg reduction in systolic blood pressure achieved, both types of drug reduced the risk of events by about 17% (both drugs combined HR 0.83, 95% CI 0.79 to 0.87).
There was no evidence that more intensive blood pressure lowering was more effective than less intensive therapy. There was also no evidence of a difference in effectiveness between different classes of blood pressure lowering drugs (full results presented).
There was no evidence that the glomerular filtration rate altered the effectiveness of treatment, but the absolute effect was greater in people with rates less than 60mL/min/1.73m² (NNT 35), than in those with higher rates (NNT 53). The presence of proteinuria was not found to alter the effectiveness of treatment.
There was some evidence of publication bias (Egger’s test p=0.05), but further analysis did not suggest that this materially affected the results. Further results, including those for secondary outcomes, were reported.