UCL researchers find that blood pressure is being measured all wrong

GPs must scrap traditional methods of measuring blood pressure as thousands of patients are being missed, researchers warn today.

They are urging doctors to switch to a new technique whereby patients are sent home with portable devices to wear for 24 hours.

University College London researchers have shown that this is far more effective than GPs taking a one-off reading with an inflatable cuff.

In the largest study of its kind, they found that the devices were 50 per cent more accurate at predicting whether patients would die from heart disease.

Furthermore, they discovered that almost a fifth of adults with normal blood pressure readings using the traditional method actually had high blood pressure.

These patients – termed as having ‘masked’ high blood pressure – would ordinarily be sent away by GPs without treatment.

GPs must scrap traditional methods of measuring blood pressure as thousands of patients are being missed, researchers warn. Devices worn for 24 hours are better, they add (stock)


Low-salt diets packed with fruit and vegetables lower blood pressure more than medication after just four weeks, a Harvard University study suggested in November 2017.

Cutting out salt and eating lots of fruit, vegetables and low-fat dairy, reduces people with high blood pressure’s results by an average of 21 mm Hg, the research adds.

To put that into context, the Food and Drug Administration (FDA), the US’ drug-approving body, will not accept anti-hypertension medications unless they lower blood pressure by at least 3-4 mm Hg.

Most medications typically reduce hypertension readings by between 10 and 15 mm Hg, but come with side effects including fatigue, dizziness and headache.

Study author Dr Lawrence Appel said: ‘What we’re observing from the combined dietary intervention is a reduction in systolic blood pressure as high as, if not greater than, that achieved with prescription drugs.

‘It’s an important message to patients that they can get a lot of mileage out of adhering to a healthy and low-sodium diet.’

Around 32 percent of adults in the US, and one in four in the UK, have high blood pressure, which puts them at risk of heart disease and stroke.

The researchers analyzed 412 people with early-stage hypertension who were not taking high blood pressure medication.

Some of the study’s participants were fed a ‘DASH (Dietary Approaches to Stop Hypertension) diet’, which includes lots of fruit, vegetables and low-fat dairy products, with minimal saturated fat.

The remaining participants ate a typical American diet.

All of the participants were fed different sodium levels equaling around 0.5, one or two teaspoons of salt a day over four weeks with five-day breaks in between.

Device use is ‘patchy’ across the UK

Up to a quarter of adults in the UK have high blood pressure but nearly half, six million, have never been diagnosed.

It is known as a silent killer as there are no symptoms but it greatly increases the risk of heart attacks, strokes, kidney disease and dementia.

The portable devices – or ambulatory blood pressure monitors (ABMPs) – cost between £500 and £1,000 and there is normally one per GP surgery.

They measure the blood pressure at 20 to 30 minute intervals for a period of 24 hours when patients go about their daily routines.

For this reason they are far more accurate as many patients with high blood pressure have normal readings when sat in a chair.

They have been increasingly adopted by GPs since 2011 when the health watchdog Nice said they were highly effective.

But researchers say their use is still ‘patchy’ across the UK.

Many surgeries still haven’t bought one – and even if they have, one is not enough to share between 7,000 patients on the register.

‘This research is a clear game-changer’

This study – published in the New England Journal of Medicine – involved the records of 63,910 patients over a 10 year period.

They had all had their blood pressure measured using the traditional method or the new portable device technique.

Researchers compared their accuracy of predicting whether patients died of heart disease over the ten years.

The devices were found to be on average 50 per cent more accurate at predicting death, although this varied slightly amongst age groups and sex.

Importantly, the study also found that those patients with ‘masked’ high blood pressure -who had a normal reading in traditional method- were the most likely to die.

They had a higher chance of dying of cardiovascular disease than those patients who were being treated for high blood pressure.

The most likely reason is that they were not being prescribed treatment to lower the blood pressure as doctors presumed they were normal.

Professor Bryan Williams, the lead author, who is chair of medicine at University College London, said: ‘This research is a clear game-changer, as for the first time, it definitively shows that blood pressure measured regularly during a 24 hour period predicts the risk of heart disease, stroke and death much better than blood pressure measured in a doctor’s surgery or clinic.

‘Quite simply, measuring blood pressure over 24 hours is what doctors and medics should be using to make clinical decisions about treatment.

‘With a much more accurate assessment of a patient’s blood pressure, doctors will be able to provide the most effective treatments at the earliest opportunity, which will save many more lives.

‘With one billion people around the world having high blood pressure, this study, the largest ever of its kind, should lead to changes in clinical practice across the world, with the use of ABPM becoming much more common place.’

Many patients experience high blood pressure when waiting to be tested (stock)

GP waiting rooms increase people’s blood pressures

Another disadvantage with the traditional method is that many patients experience sudden high blood pressure when they walk into the consulting room.

This is known as ‘white-collar syndrome’ and occurs because patients are anxious or nervous.

Normally GPs suspect their reading is wrong because they are otherwise healthy and they are sent home to measure their blood pressure themselves.

Professor Mark Caulfield, an expert in cardiovascular genetics at Queen Mary University of London, said: ‘This important paper confirms that 24-hour ambulatory blood pressure which makes many more measurements compared to conventional clinic blood pressure is superior in defining patients risk of adverse outcome from heart disease and stroke.’

An ideal blood pressure reading is between 90/60 millimetres of mercury (mmHg) and 120/80 millimetres of mercury.

If the blood pressure is significantly higher, it exerts extra strain on the blood vessels and main organs.

Last month the British Heart Foundation warned that the condition was a leading cause of death and disability and costing the NHS £2 billion annually.

Leave a Reply

Your email address will not be published. Required fields are marked *