Beta-blockers
'increase diabetes risk by 50 per cent'
by JENNY HOPE
Patients taking beta-blockers for their
blood pressure have a 50 per cent higher risk of developing diabetes compared
to being on newer drugs, researchers have revealed.
For the first time, a new study reveals
the risk of using the older drugs which are no longer recommended for treating
high blood pressure.
Patients taking beta-blockers and
diuretics - standard medication for over 30 years - are at far greater risk of
becoming diabetic.
Not only are they less effective than
newer medication, but they actually hasten and, in some cases, induce the
disease in blood pressure patients - who are already at high risk.
This means at least 8,000 Britons taking
the older drugs are getting diabetes unnecessarily each year as a result.
Until earlier this year, around two
million patients have been on beta blocker based treatments at any one time.
But new guidance to doctors says newer
ace inhibitors and calcium channel blockers should be the first choice
treatment for the millions of Britons treated for high blood pressure.
The change came after research found the
older drugs were only half as effective at stopping strokes and heart attacks.
Beta blockers such as atenolol should no longer be prescribed for the problem,
said the guidelines from the National Institute for Clinical Excellence.
But now a new clinical trial released
yesterday show they also bring a 50 per cent higher risk of developing
diabetes.
Although many patients currently taking
them are being switched by their GPs to newer drugs when they go for a
scheduled check-up, they remain in wide use.
Beta blockers are still considered the
best treatment for other conditions such as angina, and doctors have warned
patients not to stop taking them without medical advice as sudden withdrawal
may trigger a heart attack.
Professor Neil Poulter,
Co-Director of the International Centre for Circulatory Health, Imperial
College London, who led the trial, said: 'Chances of a patient with raised
blood pressure developing diabetes can be cut by the newer treatment
irrespective of the patients initial level of risk.
'Many new cases of diabetes could be
prevented as a result, if GPs avoid prescribing the older treatments to
hypertensive patients unless they specifically require them.'
Benefits
outweigh risk in some cases
Experts stress that, for remaining beta
blocker patients, the benefits in lowering blood pressure still massively
outweigh the diabetes risk, so they should not suddenly stop taking them.
But they also called for all patients to
be switched to the new drugs as soon as possible.
The trial results were released at the World
Congress of Cardiology in
The study looked at 14,000 patients in
the
The remainder were prescribed a calcium
channel blocker called amlodipine and the
ace-inhibitor perindopril, and in this group 34 per
cent fewer patients developed diabetes over three years.
The study suggests the ace-inhibitor
provides protection against the condition while the other drug is neutral.
But the beta blocker and diuretic
combination actually has an adverse effect in encouraging diabetes.
Having diabetes and high blood pressure
together greatly increases the risk of heart attacks, strokes and kidney
disease.
Professor Poulter,
Professor of Preventive Cardiovascular Medicine, said: 'The result emphatically
adds to the evidence that beta blockers and diuretics can exacerbate that risk.
They have been great drugs for a long time but there is a down side and we have
to stop pretending that it's ok to give people diabetes. These cases are
absolutely unnecessary.
'The newer drugs are better at stroke
prevention, more cost effective and don't give you diabetes.'
He estimates around 8,000 cases of
diabetes each year in the
But, he added, older drugs were not
responsible for fuelling a surge in cases in recent years - nearly three
million people have diabetes, although one million are unaware of it.
Obesity and lack of physical activity
have been much bigger risk factors.
Professor Poulter
stressed that patients on beta blockers must not suddenly stop taking them. 'They
are still the right drugs for some people and your doctor can advise you'.
Prof Peter Weissberg,
medical director of the British Heart Foundation charity, said: 'The evidence
shows there is a better outlook for the newer drugs in delaying or preventing
diabetes in patients with high blood pressure and this has led to the new
guidelines.
'The message is getting through to GPs,
but there are other important reasons for being on a beta blocker, such as
angina, arrhythmia and heart failure, where they are life-saving.
'Patients taking a beta blocker should
not stop taking them without seeing a doctor. If you stop it suddenly, then it
may cause a major event, possibly a heart attack.'
Amanda Eden, care adviser at the
Diabetes UK charity, said: 'These findings are interesting, as we know that
high blood pressure is both a risk factor and complication of diabetes.
'Nevertheless, when it comes to
prevention, other factors, such as leading an active lifestyle and following a
healthy diet are also essential.'
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