More than 1.5 million prescriptions for rosiglitazone and pioglitazone were issued in England alone last year.

The researchers, led by the University of East Anglia, suggest fluid retention caused by the drugs may be to blame.

Writing in the journal Diabetes Care, they call for a rethink on the drugs by the regulatory authorities.

Patients are advised not to stop taking the drugs, but to consult their GP if they have concerns.

Prescriptions for the drugs, known as thiazolidinediones, have doubled over the last three years.

Rosiglitazone, brand name Avandia, was linked to heart attacks by research published earlier this year.

The latest analysis of data estimates that one in every 50 people taking the drugs over a 26-month period will require hospital admission because of heart failure.
Lead researcher Dr Yoon Loke said: "This means that the diabetes drugs could have caused thousands of additional cases of heart failure, creating a substantial burden on hard-pressed NHS services."

The researchers also looked in detail at more than 200 cases of patients with heart failure related to the diabetes drugs and found that the problem developed even in patients taking low doses of the drugs.

While heart failure is often thought to be a problem affecting older patients, the researchers also found that one quarter of cases occurred in people younger than 60.

http://news.bbc.co.uk/2/hi/health/6914434.stm