Study on diastolic blood pressure could change how doctors treat some patients with hypertension

Medical pills for hypertension next to equipment for measuring blood pressure in the background.

Intensive lowering of diastolic blood pressure—the bottom reading in blood pressure measurements— does not appear to be linked to an increased risk of heart attacks and other adverse cardiovascular outcomes, according to a large new study. The findings could change how physicians interpret this reading and how some patients with hypertension are treated in the future, researchers suggest.

The NHLBI’s landmark SPRINT study indicated that intensive blood pressure management—lowering systolic blood pressure to less than 120 millimeters of mercury (mm Hg)—can significantly reduce the risk of heart disease, stroke, and death compared to blood pressure targets of less than 140 mm Hg. By contrast, recent observational studies suggest that intensive lowering of diastolic blood pressure might increase the risk of adverse cardiovascular events, including heart attack.

To determine whether very low diastolic blood pressure triggered cardiovascular events, researchers analyzed genetic and health data in over 47,000 adult patients enrolled in five study groups worldwide: ARIC, the Framingham Heart Study, the Cardiovascular Health Study, the Multi-Ethnic Study of Atherosclerosis, and the Women’s Health Initiative. The patients had a median age of 60 years and 77% were women. The researchers found no evidence of an increased risk of heart attack when a patient’s diastolic pressure fell to as low as 50 mm Hg. They also found no lower limit of what is considered normal diastolic pressure. As many doctors focus on keeping the bottom blood pressure reading within the 70-90 mm Hg range, the researchers suggest that some patients with high blood pressure may have been undertreated in the past.

The study is in agreement with the SPRINT findings indicating that lower blood pressure targets are better for your health, the researchers said. Partly funded by the NHLBI, the new study appeared in Circulation.