NEW YORK (Reuters Health) - Measuring blood pressure outside the clinic using 24-hour monitoring equipment is important for identifying and managing hypertension in African-Americans, a new study shows.
That’s because measurements in doctors’ offices and clinics may not accurately reflect blood pressure levels that a person experiences at home, work, and while asleep - and this may be a particularly important issue for African-Americans, researchers say.
Higher daytime and nighttime blood pressure measured outside the doctor’s office is associated with an increased risk of coronary artery disease, stroke, and death, they explain.
“Blood pressure varies in a complex and irregular way even at steady-state condition,” Dr. Yuichiro Yano from Duke University, Durham, North Carolina told Reuters Health.
“Our study suggests that higher blood pressure measurements outside versus inside the clinic had stronger association with cardiovascular disease and all-cause mortality,” said Yano, who worked on the study. “This means that, even if your blood pressure levels are not in the hypertensive range when measured in the clinic but in the hypertensive range when measured outside of the clinic, you may have a high risk for cardiovascular disease and all-cause mortality.”
African American individuals are more likely than individuals with other racial/ethnic background to have hypertension and its consequences, and they have been shown to have higher daytime and nighttime blood pressure levels than white or Asian individuals.
Yano’s team used information from the Jackson Heart Study to investigate the associations of daytime and nighttime blood pressure levels with cardiovascular disease events (heart attack, coronary heart disease, and stroke) and death from any cause and whether such associations are independent of blood pressure measured in the clinic. The study included 1,034 African American adults taking antihypertensive medication.
Over the course of more than a decade, each 13.5-point increase in daytime systolic blood pressure (the “top” number) compared to the measurement in the clinic was associated with 53% higher risk of cardiovascular disease events and 13% higher risk of death from any cause, the researchers reported in JAMA Cardiology.
Similarly, every 15.5-point increase in nighttime blood pressure compared to pressure in the clinic was associated with a 48% higher risk of cardiovascular disease events and a 24% higher risk of death from any cause.
Increased daytime and nighttime diastolic blood pressure (the “bottom” number) were also associated with increased risks of cardiovascular disease events and death from any cause.
The increased risk of cardiovascular disease events was higher for people who were not taking their blood pressure medication than for those who were taking their blood pressure medication.
After the researchers took other risk factors into account, high daytime and nighttime blood pressure were still associated with an increased risk of cardiovascular disease events but not with a significantly increased risk of death from any cause.
“Measurement of daytime and nighttime blood pressure using ambulatory monitoring during a 24-hour period may help identify African American individuals who have an increased cardiovascular disease risk,” the researchers conclude.
SOURCE: bit.ly/2Z7OHwv JAMA Cardiology, online August 14, 2019.