Further support for the idea of giving antihypertensive drugs to everyone over a certain age, regardless of their blood pressure, has come from the largest meta-analysis of randomised trials of blood pressure reduction to date.
The meta-analysis, published in the British Medical Journal (BMJ 2009;338:b1665), was conducted by Drs Malcolm Law, Joan Morris, and Nicholas Wald from the Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine, Queen Mary University of London.
They included 147 trials in the analysis: 108 trials which studied differences in blood pressure between study drug and placebo (or control) and 46 trials comparing different antihypertensive drugs. Seven trials fell into both categories.
Results showed that lowering systolic blood pressure by 10 mmHg or diastolic blood pressure by 5 mmHg using any of the main classes of blood pressure lowering drugs, reduces coronary heart disease (CHD) events (fatal and non-fatal) by about a quarter, stroke by about a third, and heart failure by about a quarter. These reductions occurred regardless of the presence or absence of vascular disease and of blood pressure before treatment, with no increase in non-vascular mortality.
The authors note that with the exception of the special short term effect of beta blockers in acute myocardial infarction, the preventive effect of all classes of blood pressure lowering drugs is the same or similar in people with and without a history of cardiovascular disease, so there is no reason to use these drugs for secondary prevention but not for primary prevention.
They add that reduction in events is also the same in people with and without high blood pressure. “There is benefit in lowering blood pressure in anyone at sufficient cardiovascular risk whatever their blood pressure, so avoiding the need to measure blood pressure routinely,” they write.
The researchers comment: “Our results support the view that blood pressure lowering drugs should no longer be regarded as treatment for hypertension in the same way that statins are now no longer regarded as treatment for hypercholesterolaemia. Consideration should be given to replacing current policies that focus on routinely measuring blood pressure with policies that focus on routinely lowering blood pressure”.
As cardiovascular risk is known to increase with age, the authors conclude that: “Our results indicate the importance of lowering blood pressure in everyone over a certain age, rather than measuring it in everyone and treating it in some”.