Many people get higher blood pressure readings in a doctor’s office than they do elsewhere: research suggests that this phenomenon, known as “white coat hypertension,” affects about one in five adults. But can we assume that a patient’s anxious response to the clinical setting is wholly responsible for that difference—and that out-of-office monitoring doesn’t offer useful information? Recent research has hinted that such patients may actually have underlying risk, and a new study tells us that is emphatically true: Compared with people who have normal blood pressure, patients with untreated white coat hypertension were shown not only to carry greater risk for heart disease but also to be twice as likely to die from it.
“Our findings underscore the importance of identifying people with this condition,” said Jordana Cohen, MD, MSCE, who led the study team. “We believe individuals with isolated in-office hypertension – those who are not taking blood pressure medication – should be closely monitored for transition to sustained hypertension—that is, elevated blood pressure both at home and the doctor’s office.” She noted that those who were already taking antihypertensive medications had no increased risk of heart disease or death.
The study team performed a systematic review and meta-analysis that pooled data from 27 studies, which followed more than 60,000 patients. Each patient’s blood pressure had been measured in-office and either at home or as the patient moved through the day, and the data showed how they fared for at least three years after the blood pressure monitoring. Compared to people with normal blood pressure both in the physician’s office and at home, the white coat hypertension patients who were not on antihypertensive medication had a 36 percent increased risk of heart disease, a 33 percent increased risk of death, and more than double the risk of death due to heart disease. “In addition to blood pressure monitoring,” Dr. Cohen said, “we advise individuals with untreated white coat hypertension to engage in lifestyle modifications, including smoking cessation, reduction in their alcohol intake, and improvements to their diet and exercise regimens.”
The findings also have implications for white coat hypertension patients who are on antihypertensive treatment, Dr. Cohen added. These patients could be harmed by overly aggressive treatment—which could lead to dangerously low blood pressures outside of the office as well as unnecessary side effects. In general, “the findings support the pressing need for increased out-of-office blood pressure monitoring nationwide,” she said.
The research team noted that more studies are needed to investigate interventions to reduce the cardiac risk of white coat hypertension. In future work, Dr. Cohen will also seek to understand more about the white coat phenomenon: Which devices reflect it most accurately? Do these patients’ blood pressure readings fluctuate in certain situations? And what does that tendency to fluctuate signify overall?