24-Hour Monitoring May Unmask High Blood Pressure in African-Americans


Medical Centre

(This article was adapted from a release from the American Heart Association).

Wearing a 24-hour monitoring device may help identify African-Americans who have masked or undetected high blood pressure, according to a new study by researchers in CUMC's Center for Behavioral Cardiovascular Health. The study was published online May 16 in the journal Hypertension.

Masked hypertension is normal blood pressure in the doctor’s office but high readings outside the clinic. It is particularly prevalent in African-Americans, approaching 30 percent to 50 percent in some studies, and may be a precursor of sustained hypertension measured in the clinic.

To discover how often masked hypertension progresses in a group of African-Americans, cardiologist Marwah Abdalla, MD, MPH, assistant professor of medicine, used ambulatory blood pressure monitoring to obtain readings of blood pressure over 24 hours as individuals performed normal daily activities.

The study included 317 African-Americans in the Jackson Heart Study, an ongoing, population-based study in Jackson, Miss., that examines the factors associated with heart disease among African-Americans.

At the beginning of the study, participants did not have high blood pressure when measured in the clinic and were not taking high blood pressure medication. They wore ambulatory blood pressure monitors at the first clinic visit and their readings were compared with two taken at subsequent clinic visits. Participants were followed for an average of 8.1 years and 187 developed high blood pressure.

The study found that 79.2 percent of participants with masked hypertension developed clinic high blood pressure compared with only 42.2 percent of participants without masked hypertension.

“Catching masked hypertension is important because if left undiagnosed, masked hypertension can lead to additional health and cardiac complications and is associated with an increased risk of clinic hypertension,” says Dr. Abdalla. “Our study shows that ambulatory blood pressure monitoring can be used to identify African-Americans who are at an increased risk for developing clinic hypertension.”

In a commentary about the study, hypertension experts from UC-Irvine wrote that the "data underscore the urgent need for the first proper randomized controlled trial to address the nagging question: Does medication management of masked hypertension prevent heart attacks, strokes, and other major cardiovascular and renal complications of hypertension?"