Blood pressure-lowering drugs should be offered to all individuals at high risk of having a heart attack or stroke regardless of their blood pressure at the start of treatment, according to the largest meta-analysis conducted to date involving over 600,000 people, published in The Lancet.
The authors call for an urgent revision of current blood pressure-lowering guidelines, including those of NICE and the European Society of Hypertension, that have recently relaxed blood pressure targets from 130/85 mmHg to 140/90 mmHg, and for the elderly to even higher targets of 150/90 mmHg.
They also recommend a shift from rigid blood pressure targets to individualised risk-based targets, even when blood pressure is below 130 mmHg before treatment.
High blood pressure, the leading cause of heart disease and stroke, affects more than one billion individuals worldwide, and kills 9.4 million people every year. The benefit of lowering blood pressure in patients with substantially raised blood pressures is well established.
But uncertainty remains about whether to treat people with lower blood pressures or with previous disease, and which drugs to use.
This study was funded by the National Institute for Health Research (NIHR) through the NIHR Oxford Biomedical Research Centre (BRC) and a NIHR Career Development Fellowship, and Oxford Martin School.
The BRC is a collaboration between Oxford University Hospitals NHS Trust and the University of Oxford to fund medical research that can benefit NHS care.
In this study, Professor Kazem Rahimi (pictured) from The George Institute for Global Health at the University of Oxford in the UK and colleagues analysed the findings of 123 large-scale randomised trials comparing different blood pressure targets from January 1966 to July 2015.
They found that treatment with any of the main classes of blood pressure-lowering drugs significantly the reduced risk of major cardiovascular events, stroke, heart failure, and death proportional to the extent to which blood pressure was lowered.
Overall, every 10 mmHg reduction in systolic blood pressure reduced the risks of major cardiovascular disease events and heart disease by about one fifth, and stroke and heart failure by about a quarter, and the risk of death from any cause by 13%.
Importantly, these reductions in disease were similar across a wide range of high risk patients including those with a history of cardiovascular disease, heart failure, diabetes, and kidney disease, irrespective of whether their blood pressure was already low (less than 130 mmHg) to begin with.
None of the five major drug classes examined was found to be better than another at protecting against cardiovascular events, with a few exceptions—an extra protective effect of calcium channel blockers in preventing stroke, an extra effect of diuretics in preventing heart failure, and a weaker effect of beta blockers in preventing major cardiovascular outcomes, stroke, and renal failure, and a significantly increased risk of death in some patients, when compared with other drug classes.
Professor Rahimi said: “Our findings clearly show that treating blood pressure to a lower level than currently recommended could greatly reduce the incidence of cardiovascular disease and potentially save millions of lives if the treatment was widely implemented.
“The results provide strong support for reducing systolic blood pressure to less than 130 mmHg, and blood pressure-lowering drugs should be offered to all patients at high risk of having a heart attack or stroke, whatever their reason for being at risk.”
Writing in a linked Comment, Professor Stephane Laurent from the University Paris Descartes, Paris, France discusses whether there is enough evidence for shifting from rigid to risk-based blood pressure targets.
He said: “Because energetic lowering of blood pressure seems safe and beneficial to patients, there is no reason not to apply it to high-risk patients. The prevalence of uncontrolled hypertension is elevated worldwide, particularly in patients with hypertension who are at high risk of cardiovascular complications.”