People who have high blood pressure readings at the doctor’s office and normal readings at home may have “white coat” hypertension, according to a new study reported in Hypertension: Journal of the American Heart Association

The study found that a third of the patients thought to have resistant hypertension – which remains above treatment goals despite drug intervention – actually had the higher readings only while in a medical environment. The monitoring used was ambulatory, meaning the blood pressure of the subjects was checked at regular intervals under normal living and working conditions.

“Ambulatory monitoring showed that many of these patients’ blood pressures were in the normal range when they were at home or participating in their usual activities,” said Alejandro de la Sierra, M.D., lead author of the study and director of internal medicine at Hospital Mutua Terrassa, University of Barcelona in Spain. “While those who actually had ‘white coat’ hypertension are not risk free, their cardiovascular outcomes are much better.”

The researchers found:

• More women (42 percent) had “white coat” hypertension than men (34 percent).
• Those with true resistant hypertension tended to be slightly younger and male, with a longer duration of hypertension and a worse cardiovascular risk profile.

“Those with true resistant hypertension showed high blood pressure at work, during the day and at night,” de la Sierra said. “The true resistant group also was more likely to have blood pressures that abnormally rose during the night when they were sleeping.”

The study included 69,045 patients with hypertension — defined as systolic blood pressure of 140 millimeters of mercury (mm Hg) or above and diastolic blood pressure of 90 mm Hg or above — in the Spanish Ambulatory Blood Pressure registry. Fifty-one percent were men and their average age was 64 years.

“Physicians should be encouraged to use ambulatory monitoring to confirm resistant hypertension in their patients as it would ensure the most effect treatment options are used,” de la Sierra said. “Patients benefit by knowing whether their blood pressure is normal during daily activities or still needs the reinforcement of dietary and drug measures to achieve the goal.”

Co-authors are Julian Segura, M.D.; Jose R. Banegas, M.D.; Manuel Gorostidi, M.D.; Juan J de la Cruz, Ph.D.; Pedro Armario, M.D.; Anna Oliveras, M.D.; Luis M. Ruilope, M.D.