Twenty-nine trials (n=162,341) were included in the review.
Stroke.
Regimens based on ACE inhibitors, calcium antagonists or ARBs statistically significantly reduced the risk of stroke compared with placebo, as did more intensive BP-lowering regimens compared with less intensive ones. Differences between different active treatment regimens were not statistically significant and the RRs were all close to 1.
CHD.
Regimens based on ACE inhibitors or calcium antagonists had small and just statistically significant beneficial effects on the risk of CHD compared with placebo. However, the differences between ARB and placebo, and between more intensive and less intensive BP-lowering regimens, were not statistically significant. Differences between different active treatment regimens were not significant and the RRs were all close to 1.
Heart failure (that caused death or hospital admission).
Regimens based on ACE inhibitors or ARBs had statistically significantly beneficial effects on the risk of heart failure compared with placebo. However, the differences between calcium antagonists and placebo, and between more intensive and less intensive BP-lowering regimens, were not statistically significant; there was a tendency for calcium antagonists to increase the risk of heart failure. The difference between calcium antagonists and other active treatments was significantly in favour of ACE inhibitors and diuretics or beta-blockers.
Major cardiovascular events.
Regimens based on ACE inhibitors, calcium antagonists or ARBs statistically significantly reduced the risk of stroke compared with placebo, as did more intensive BP-lowering regimens compared with less intensive ones. Differences between different active treatment regimens were not statistically significant and the RRs were all close to 1.
Cardiovascular death.
Regimens based on ACE inhibitors or calcium antagonists had small and just statistically significant beneficial effects on the risk of cardiovascular death compared with placebo. However, the differences between ARBs and placebo, and between more intensive and less intensive BP-lowering regimen, were not statistically significant. Differences between different active treatment regimens were not significant and the RRs were all close to 1.
Total mortality.
Regimens based on ACE inhibitors had a statistically significant beneficial effect on total mortality compared with placebo. However, differences between ARBs or calcium antagonists and placebo, and between more intensive and less intensive BP-lowering regimens, were not statistically significant. Differences between different active treatment regimens were not significant and the RRs were again all close to 1.
Effect of reductions in BP.
For all seven randomised comparisons, the weighted mean difference in BP was directly associated with differences in the risk of stroke, CHD, major cardiovascular events, cardiovascular death and total mortality, but not with the risk of heart failure.