High blood pressure may increase risk of strokes: Study

A study by Michigan Medicine discovered that elevated systolic blood pressure (the upper number on a blood pressure reading, indicating the force with which the heart pumps blood into the arteries) heightens the risk of the two most prevalent types of strokes over time. The research analysed the average systolic blood pressure years prior to the first stroke in more than 40,000 adults aged 18 and above who had no previous history of stroke.

Researchers studied three types of strokes: ischemic stroke, which involves a clot blocking blood flow to the brain and accounts for over 85% of all strokes; intracerebral haemorrhage, which is bleeding within the brain; and subarachnoid haemorrhage, which involves bleeding between the brain and the surrounding tissues. Their findings indicated that having an average systolic blood pressure 10 mm Hg higher than normal increased the risk of overall stroke and ischemic stroke by 20%, and the risk of intracerebral hemorrhage by 31%.

"Our results suggest that early diagnosis and sustained control of high blood pressure over the lifespan are critical to preventing stroke, ischemic stroke and intracerebral haemorrhage, especially in Black and Hispanic patients who are more likely to have uncontrolled hypertension than white patients," said senior author Deborah A. Levine, M.D., M.P.H., professor of internal medicine and neurology at University of Michigan Medical School.

Black patients faced a 20% greater risk of ischemic stroke and a 67% higher risk of intracerebral haemorrhage than white patients. In contrast, Hispanic patients had a 281%



increased risk of subarachnoid hemorrhage, but no elevated risk for other types of stroke compared to white patients.

While Black and Hispanic patients faced a greater risk of stroke, researchers found minimal evidence indicating that race and ethnicity influenced the link between cumulative systolic blood pressure and the type of stroke experienced by any patient.

"Examining racial inequities advances our understanding of the social, economic and political structures that affect health behaviours and risk for stroke among racial and ethnic minority groups," said Kimson E. Johnson, PhD, M.A., M.S.W., first author and postdoctoral research fellow at the University of Michigan.

Although systolic blood pressure is a modifiable target for preventing stroke and other cardiovascular diseases, a national study from 2020 revealed that blood pressure control in the United States deteriorated from 2013 to 2018, particularly among Black and Hispanic adults. According to Levine, self-monitoring of blood pressure enhances diagnosis and control, and is both accurate and cost-effective, yet it remains underutilised.

"Two major barriers to self-monitoring of blood pressure are lack of patient education and insurance not covering the home blood pressure monitors, which cost $50 or more," she said.

"Health care systems and providers must educate and urge their patients to do home blood pressure monitoring, and insurers must pay for home blood pressure monitors to optimise people's blood pressure and reduce their chances of having a stroke."