The new findings appear in the journal Hypertension.
Treatment-resistant high blood pressure occurs when a person’s blood pressure remains high despite taking at least three different drugs to lower it.
Of 8,295 people included in the study, 37% of those who were believed to have treatment-resistant hypertension actually had “white coat hypertension.” That’s according to 24-hour blood ambulatory pressure monitoring. In that type of monitoring, blood pressure is measured at regular intervals outside the doctor’s office throughout the day.
“Ambulatory blood pressure monitoring continues to be needed and must be encouraged for a correct diagnosis and management of all hypertensive patients not controlled on three or more antihypertensive drugs,” conclude the researchers, who were led by Alejandro de la Sierra, MD, director of internal medicine at Hospital Mutua Terrassa at the University of Barcelona in Spain.
A higher percentage of women than men had white coat hypertension, the study shows. People who really had treatment-resistant hypertension were more likely to smoke, have a history of diabetes, and other heart disease risk factors.
“There is no question that ambulatory blood pressure monitoring is the gold standard, but the question is, can everyone afford it. And the answer is probably not at the present time with the technology that we have,” says Thomas D. Giles, MD. Giles is professor of medicine at Tulane University School of Medicine in New Orleans and the current president of American Society of Hypertension specialists’ program.
The cost for ambulatory blood pressure monitoring can be up to $500 at some clinics, and only some plans reimburse for the test.
“Hard-to-treat hypertension means giving a lot of drugs and the blood pressure is not coming down,” he says.
If it is truly resistant hypertension, there will be other signs in addition to elevated blood pressure, including kidney disease, he says.