“That’s not me!” exclaimed the 52-year-old stock analyst, a new patient, after I had found her blood pressure high at 150/90. “Just last week it was perfectly normal when I took it at my local CVS.” The numbers remained elevated on two subsequent office visits, so I asked her to purchase a digital blood-pressure monitor for use at home. Repeated checks at different times of the day were normal. So the likely diagnosis? White-coat hypertension, which is high blood pressure that occurs only when a person is in a doctor’s office.
White-coat hypertension was once only hinted at by the variation in blood pressure taken by different professionals at different times. The arrival of the home blood-pressure monitor showed that the diagnosis was plausible. The advent of the ambulatory blood-pressure monitor, which is worn for 24 hours and records blood pressure every 15 minutes, made the diagnosis definitive.
The condition can strike not only when in the room with an authority figure wearing a long white coat and a stethoscope but even in the waiting room in anticipation of such an encounter. Nowadays, it even has its own official diagnostic code number for billing purposes. The number gets quite a workout, given that 30 percent to 40 percent of people with hypertension have this variety.
The why and the who
The theory is that the patient’s adrenaline surges because of the stress of going to the doctor. But there must be more to it than that, because ambulatory readings have shown that the same people can have perfectly normal blood pressure in other high-stress situations, such as public speaking. There are even those who have elevated blood pressure during an office visit, normal readings with a home monitor, and elevated ones with an ambulatory monitor.
In studies that have looked at the demographics of this disorder, age seems to be more of a factor than ethnic origin, and men and women are similarly affected. Compared with people who have normal pressure, those with white-coat hypertension have increased systemic vascular resistance (a measure of susceptibility to high blood pressure), and an increased prevalence of such risk factors as obesity, high triglycerides, elevated LDL (bad) cholesterol, and blood sugar levels in the prediabetic range. Ambulatory recordings also reveal that they have greater variations in blood-pressure measurements than people with normal blood pressure.