People at risk of a heart attack or stroke could benefit from blood pressure-lowering drugs even if their blood pressure is considered in the normal, healthy range, a study suggests.
If such drugs were offered to people with cardiac risks regardless of their blood pressure at the beginning of treatment it could save millions of lives, researchers at the University of Oxford in Great Britain said.
For the study, the team analyzed more than 120 medical trials encompassing around 600,000 people conducted over two decades, saying their findings are a call for an urgent review of existing blood pressure treatment guidelines.
"Our findings clearly show that treating blood pressure to a lower level than currently recommended could greatly reduce the incidence of cardiovascular disease," if widely implemented, said study lead author Kazem Rahimi.
High blood pressure has long been identified as a factor in higher risks of heart disease and stroke, and afflicts more than a billion people around the globe, including one out of three U.S. adults, the researchers note in their study appearing in The Lancet.
Blood pressure is recorded in millimeters of mercury (mmHg) as two numbers in a ratio: "systolic" pressure inside the arteries when the heart beats as the top number, and "diastolic" pressure between heartbeats, as the heart rests and refills with blood.
"Normal" blood pressure is considered at 120/80 or below, and is considered "high" at 140/90 or above, according to the American Heart Association.
The researchers said their study showed that for every reduction in systolic pressure of 10 mmHg, the risk of heart attack was reduced by a fifth and that of a stroke around a quarter.
"Importantly, these reductions in disease were similar across a wide range of high risk patients ... irrespective of whether their blood pressure was already low (less than 130 mmHg) to begin with," the study authors said.
Current guidelines in Great Britain suggest medication should be prescribed only when blood pressure levels reach 140 mmHg.
Some experts, like Liam Smeeth of the London School of Hygiene and Tropical Medicine, said they thought the study's findings were important but did offer some cautions.
"One important caveat is that not everyone will be able to tolerate having their blood pressure reduced to low levels, and there is a need to balance possible drug side effects and likely benefits," Smeeth said.
