Study Upends Preconceptions of Blood Pressure Management
New research could change how doctors treat some patients with hypertension, as they find that low diastolic blood pressure can be benign in blood pressure management.
The study by researchers at NUI Galway, Johns Hopkins University and Harvard Medical School found no evidence that diastolic blood pressure can be harmful to patients when reduced to levels that were previously considered to be too low. High blood pressure, or hypertension, affects a quarter of men and a fifth of women. Blood pressure medications reduce both systolic and diastolic values.
Lead researcher Bill McEvoy, Professor of Preventive Cardiology at NUI Galway and a Consultant Cardiologist at University Hospital Galway, said the findings have the potential to immediately influence the clinical care of patients. The study was published in the prestigious journal Circulation.
“We now have detailed research based on genetics that provides doctors with much-needed clarity on how to treat patients who have a pattern of high systolic values – the top reading for blood pressure – but low values for the diastolic, or bottom, reading,” said Bill McEvoy, Professor of Preventive Cardiology at NUI Galway. “This type of blood pressure pattern is often seen in older adults. Old studies using less reliable research methods suggested that the risk for a heart attack began to increase when diastolic blood pressure was below 70 or above 90. Therefore, it was presumed there was a sweet-spot for the diastolic reading.”
Hypertension is a major contributor to mortality around the world, linked to heart attacks as well as brain, kidney and other diseases. It has also emerged as a risk factor for COVID severity and mortality.
Using new technologies that take into account genetic information that is unbiased, which was not the case with prior observational studies, Professor McEvoy and the international research team analysed genetic and survival data from more than 47 000 patients worldwide.
The researchers found that there is apparently no lower limit of normal for diastolic blood pressure and no evidence in this genetic analysis that diastolic blood pressure can be too low. They also found no genetic evidence of increased risk of heart disease when a patient’s diastolic blood pressure reading is as low as 50. The findings confirmed that values of the top, systolic, blood pressure reading above 120 increased the risk of heart disease and stroke.
“Because doctors often focus on keeping the bottom blood pressure reading in the 70-90 range, they may have been undertreating some adults with persistently high systolic blood pressure,” Prof McEvoy explained. “The findings of this study free up doctors to treat the systolic value when it is elevated and to not worry about the diastolic blood pressure falling too low.
“My advice now to GPs is to treat their patients with high blood pressure to a systolic level of between 100-130mmHg, where possible and without side effects, and to not worry about the diastolic blood pressure value.”
Source: News-Medical.Net
Journal information: Arvanitis, M., et al. (2021) Linear and Nonlinear Mendelian Randomization Analyses of the Association Between Diastolic Blood Pressure and Cardiovascular Events. Circulation. doi.org/10.1161/CIRCULATIONAHA.120.049819.
