Home Blood Pressure Aids Studied

Blood pressure readings taken in a doctor’s office may be far less accurate at predicting the risk of heart attack or stroke than automated measurements taken throughout the day, researchers said Wednesday.

Doctors have known for years that nervous patients often have higher blood pressure readings in their offices, a phenomenon known as white-coat hypertension.

But in a study published in today’s New England Journal of Medicine, researchers found that devices that silently measure blood pressure throughout the day and night are far better at pinpointing who is at risk among patients who have already been treated for high blood pressure.

The cost of all-day blood pressure monitoring ranges from $50 to $200, but the procedure only needs to be done over one 24-hour period.

It involves wearing a blood pressure cuff and carrying a 10-ounce Walkman-size device on a shoulder strap or clipped to the belt. Pressure is measured several times an hour. The patient keeps a diary so the doctor can see how various activities affect the pressure.

“The difference can be absolutely dramatic from the reading in the doctor’s office,” William White of the University of Connecticut School of Medicine said.

In the study, Denis Clement of Ghent University in Belgium and his colleagues found that patients with high blood pressure throughout the day had nearly twice the risk of getting a heart attack or a stroke than people who had lower blood pressure, regardless of the blood pressure reading recorded in a doctor’s office.

White, in a commentary in the Journal, said the findings showed that doctors should use a combination of self-monitoring and all-day, automated monitoring to confirm whether a patient’s blood pressure was really high.