Diabetics warned about heart failure risk

A class of drugs used by some diabetics could increase their risk of heart failure and death, experts said today.

People taking tablets known as sulphonylureas as their only therapy had a 24% to 61% increased risk of dying and up to a 30% increased risk of heart failure compared with people taking the drug metformin.

The researchers said their findings back up current UK guidance that patients should be given metformin as a first treatment for Type 2 diabetes.

Only those who cannot tolerate metformin should be given sulphonylureas as their only treatment, they said.

The researchers found no increased risk for people taking a combination of metformin and sulphonylureas medicines, although they said more research was needed.

Examples of sulphonylureas drugs include glibenclamide, gliclazide, glimerpirizide, glipizide, and gliquidone.

Lead researcher Dr Ioanna Tzoulaki, from Imperial College London, said: “When we looked at metformin and sulphonylureas together we did not see an increased risk of heart failure or death.

“This might be because the sulphonylureas dose used when it is in combination with metformin is not as high as on its own, so you might not see the effect.

“It is also possible that metformin could be protective.

“Other studies looking at the drugs together have been inconclusive.

“It’s very important that people do not stop taking their medication as a result of this study.”

Some 550,000 diabetics in the UK take sulphonylureas drugs, although few of these are thought to be taking them on their own without metformin.

Metformin works by reducing the amount of glucose the liver releases into the bloodstream and is often prescribed for Type 2 diabetics who are overweight.

Sulphonylureas drugs work by increasing the amount of insulin produced by the pancreas and are more often given to diabetics who are not overweight.

The latest study, published online in the British Medical Journal (BMJ), was based on 91,521 people in the UK with an average age of 65.

Using GP records, the patients were followed for an average of seven years.

Over that time, there were 3,588 heart attacks, 6,900 cases of congestive heart failure and 18,548 deaths.

Dr Iain Frame, director of research at Diabetes UK, said the results should be treated with caution.

“Diabetes UK would not advise people with Type 2 diabetes to stop taking sulphonylureas based on the results of this research.

“If you are concerned about taking this medication you should contact your GP or diabetes healthcare team.”