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Uncertainty exists about which blood pressure (BP)–lowering drugs to use and about whom to treat. U.K. investigators determined the efficacy of different classes of BP-lowering drugs in preventing coronary heart disease (CHD)–related events and stroke by conducting a meta-analysis of 147 randomized trials that involved 464,000 patients. The analysis included both hypertensive patients and patients in whom BP-lowering drugs were used for indications other than hypertension. Key meta-analysis findings include the following:
Compared with placebo or no treatment, β-blockers resulted in 31% fewer CHD events in patients with recent myocardial infarctions (i.e., during the previous 2 years), 13% fewer CHD events in patients with CHD but without recent MIs, and 15% fewer CHD events in patients without histories of CHD. In the absence of recent MI, other BP-lowering drugs were as effective as β-blockers in preventing CHD events among patients with histories of CHD.
Compared with placebo or no treatment, BP-lowering drugs led to significantly fewer CHD events and strokes (by 22% and 41%, respectively, when standardized to BP reductions of 10 mm Hg systolic or 5 mm Hg diastolic).
The five classes of drugs (thiazides, β-blockers, angiotensin-converting–enzyme (ACE) inhibitors, angiotensin-receptor blockers, and calcium-channel blockers) all similarly lowered rates of CHD events. Calcium-channel blockers were more effective in preventing stroke than were the others, although all drugs were more effective than no treatment.
Relative reductions in CHD events and stroke were similar among people with no histories of vascular disease and among those with prior CHD or stroke.
Regardless of patients’ pretreatment BP (as low as 110 mm Hg systolic and 70 mm Hg diastolic), BP-lowering drugs significantly lowered risk for CHD events and stroke.
With the exception of non-cardioselective β-blockers, each class of BP-lowering drugs significantly lessened risk for heart failure.
Compared with placebo or no treatment, BP-lowering drugs were associated with significantly lower all-cause mortality (by 13%). No changes in cancer incidence or nonvascular-related mortality were noted.
Law MR et al. Use of blood pressure lowering drugs in the prevention of cardiovascular disease: Meta-analysis of 147 randomised trials in the context of expectations from prospective epidemiological studies. BMJ 2009 May 19; 338:b1665. (http://dx.doi.org/10.1136/bmj.b1665)
Comment
With the exceptions of the protective effects of β-blockers within 2 years after MI and of calcium-channel blockers in preventing stroke, all BP-lowering drugs similarly affected incidence of CHD events and stroke (for a given BP). Risk was lowered in people with and without histories of vascular disease and pretreatment hypertension. The authors conclude “there is benefit in lowering blood pressure in anyone at sufficient cardiovascular risk whatever their blood pressure.”