May 8, 2010

Doctors Can Cause Rising Blood Pressure

Researchers warned recently that doctor's office visits can cause patients to have a rise in blood pressure, saying it is far worse in someone who already has high levels.

The "Ëœwhite-coat' effect, as it is being called, is due to patients becoming stressed by being in a doctor's office or a hospital.

An Australian research team said that giving people a cuff to wear for one day is a good way for checking blood pressure. The cuff has also shown that external factors affect blood pressure readings, according to one expert.

High blood pressure affects about 40 percent of adults in the UK and is a huge risk factor for heart attack, heart failure, kidney disease and stroke.

The cuff checks blood pressure regularly throughout the day -- known as ambulatory blood pressure checks -- as the patient goes about their daily lives.

The researchers monitored more than 8,500 patients who were being assessed at 11 clinics around Australia. They compared ambulatory blood pressure measurements with those taken by doctors and nurses and found that there can be a difference of as much as 29 units if a doctor checked it, compared with a rise of 17 units if a nurse took the measurement.

Differences also varied depending on the age and sex of the patient. The study also concluded that the closer a patient's blood pressure was to normal levels, the less of a difference between measurements taken by the cuff and those taken by a medical worker.

"Ambulatory blood pressure monitoring is the tool of choice to correctly diagnose high blood pressure," Professor Arduino Mangoni, who recently joined the University of Aberdeen from Flinders University in Adelaide, told BBC News.

"Clearly, if you're going to be treating a person for the rest of their life, you want to get the readings right, and often the reading in the doctor's office is much higher."

Mangoni said it was already known that there was a difference between doctors' readings and ambulatory measurements, but, what was surprising was how big the difference was in those with already high blood pressure levels.

The findings should be used to help plan new guidelines in monitoring blood pressure, he told BBC News.

"Current guidelines for the diagnosis and treatment of hypertension don't pay enough attention to the role of ambulatory monitoring, often adopting a one- size-fits-all approach which doesn't properly address different patient groups," added Mangoni.

"This is interesting research which clearly illustrates how external factors such as environment and who is checking blood pressure can have a significant impact on blood pressure readings," said Professor Graham MacGregor, chairman of the Blood Pressure Association.

"Many people feel slightly anxious when going to see a doctor, which is why we have always encouraged blood pressure measuring at home as well as in the clinic, and promotes the use of home blood pressure monitors and ambulatory testing where indicated," he said.

"This research may well be considered as part of the review of the NICE [National Institute of health and Clinical Excellence] guidelines for the treatment of hypertension which is currently being conducted, and will be released next year."

The study is published in the British Medical Journal.


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