Professor Andrea Siebenhofer-Kroitzsch of the institute for general practice at the Goethe University in Frankfurt raised her concerns at the European Association for the Study of Diabetes meeting in Vienna, Austria, this week.

She said that, although evidence pointed to an obvious mortality benefit for those with type-1 diabetes, the benefit for those with type-2 disease was ‘not very great' and came at a price.

Over 100 patients would have to be treated for several years to prevent one MI, she said. All those patients would have to accept a doubled risk of hypoglycaemia, risking unconsciousness of coma, she pointed out.

‘It so far remains unproven that lowering blood glucose to approximate the normal range of a non-diabetic has an advantage over standard care,' she said.

‘The intensity of glucose treatment should very much depend on the age of the patient.'

She said that tackling BP and lipid levels was more likely to reduce mortality rates in people with type-2 diabetes.

Read Tom Moberly's live blog from the conference