Many given blood-pressure drugs suffer ‘white-coat’ hypertension

Research suggests that many people prescribed drugs for hypertension do not have high blood pressure and are merely nervous about visiting the doctor.

a third of patients diagnosed by traditional methods with extremely high blood pressure were found to be within the normal range when measured at home

More than a third of patients diagnosed by traditional methods with extremely high blood pressure were found to be within the normal range when measured at home, a study found.

Researchers have long suspected that the “white-coat effect” was behind many diagnoses of high blood pressure, but one of the first large-scale studies suggests that numbers are even higher than previously thought.

Doctors in Britain were last month told by the health watchdog that they should send patients home with a monitor for 24 hours rather than rely on armband readings taken in the surgery, saying that millions could be misdiagnosed because of waiting-room nerves.

A recent study of over eight thousand people with high blood pressure who had not responded to treatment has found that 37 per cent did not have the problem when measured at home.

Women proved most susceptible, with 42 per cent of those diagnosed found not to have the condition, compared to 34 per cent of men, according to results published in the American Heart Association journal Hypertension.

The researchers compared traditional diagnoses with results from a monitor that checked blood pressure at regular intervals under normal living and working conditions.

“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, the lead author of the study and director of internal medicine at Hospital Mútua Terrassa, University of Barcelona.

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

The National Institute for Health and Clinical Excellence has recommended that people with two high blood pressure readings should take a third at home to rule out “white coat” syndrome, but Dr de la Sierra said measurements at home should be standard.

“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,” he 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.”

More than 8.5 million Britons have been told they have high blood pressure, defined as systolic [pumping] blood pressure of 140mmHg and diastolic [rest] pressure of 90mmHg. That total could fall dramatically if ambulatory measurement was adopted.

Some studies have shown that those with “white-coat” hypertension are more likely to go on to develop true high blood pressure, possibly as they are more prone to stress.

Dr de la Sierra said: “While those who actually had ‘white-coat’ hypertension are not risk free, their cardiovascular outcomes are much better.”

A senior cardiac nurse at the British Heart Foundation, said: “This study looked at a minority of people who still had high blood pressure despite being on at least three drugs to treat it. Visiting the doctor seemed to make some people falsely appear resistant to the effects of these drugs so the study was helpful in trying to identify which people seemed to be truly resistant and therefore more at risk of organ damage. It also adds weight to new draft guidelines to include a home blood pressure test for hypertensive patients here in the UK.”

Tagged: blood pressure, high blood pressure