Comparison of various blood pressure lowering treatments on the primary prevention of cardiovascular outcomes in recent randomised clinical trials

Randomised clinical trials completed over the past 8 to 10 years have provided much new evidence regarding the cardiovascular risks and benefits of treatment with newer blood pressure lowering drugs, particularly ACE inhibitors and calcium channel blockers (CCB). Trials of active treatment against placebo have now established that ACE inhibitors and CCBs reduce the risk of coronary heat disease and stroke in subjects with elevated blood pressure and that ACE inhibitors reduce the risk of heart failure but calcium antagonists do not. Clinical trials comparing active treatment regimens based on different blood pressure lowering drug classes, have provided convincing evidence that ACE inhibitors, CCBs, and "conventional treatment" with diuretics/beta-blockers are equally effective in the primary prevention of coronary heart disease, but that minor differences of the order of 5-12% favouring calcium antagonists may exist. The one area with a major difference is again for the primary prevention of heart failure where calcium antagonists are clearly inferior to diuretics/beta-blockers and to ACE inhibitors. There is now convincing evidence that blood pressure lowering is effective in the secondary prevention of cardiovascular outcomes in subjects with established coronary heart disease, cerebrovascular disease, diabetes and chronic kidney disease, especially diabetic nephropathy. Clinical trial evidence comprising regimens based on different drug classes for the secondary prevention of cardiovascular outcomes is still very limited. It is possible that longer differences will be found between the efficacy and safety of drugs in secondary prevention than have been reported so far in primary prevention.