Leading diabetes specialists writing in the British Medical Journal have dismissed the use of glitazone drugs to prevent the disease, arguing that lifestyle changes, such as modest weight loss and physical activity, are equally effective much safer, and cheaper.

A recent trial (DREAM) showed that GlaxoSmithKline’s Avandia (rosiglitazone) reduces the risk of developing type 2 diabetes by 62% compared to placebo in patients with pre-diabetes, but the authors of the BMJ article, lead by Prof Victor Montori of the Mayo Clinic in Rochester Minnesota, and colleagues write: “The diabetes reduction assessment with ramipril and rosiglitazone medication (DREAM) trial recently showed that rosiglitazone reduced the risk of diabetes in people at risk.

“The results have prompted aggressive marketing of rosiglitazone as a preventive therapy; some clinicians are already responding to this initiative.”

Diabetes affects about 4% of the world’s population and is associated with high financial and human costs – making its treatment and prevention a public health priority. However, the experts caution that more research is needed because one interpretation of the DREAM study could be that the drug actually treats, not prevents, diabetes.

The study, which was published in The Lancet medical journal last September, suggested that one person in 12 should be taking rosiglitazone to prevent the disease and the researchers said that giving rosiglitazone to people with impaired glucose regulation might prevent one case in seven. However, Prof Montori said that this strategy would bring harm and additional costs while the benefits for patients remain questionable.

He claimed: “If clinicians offer patients glitazones to prevent diabetes, they are offering certain inconvenience, cost and risk for largely speculative benefit” and added that several trials have assessed the ability of drugs to prevent diabetes, but none has shown that prevention with them improved outcomes important to patients.”

The BMJ article also notes that evidence is emerging of serious side effects from glitazone drugs and concluded “Clinical use of glitazones to prevent diabetes is, at present, impossible to justify because of unproved benefit on patient important outcomes or lasting effect on blood glucose levels, increased burden of disease labelling, serious adverse effects, increased economic burden, and availability of effective, less costly lifestyle measures.”

Simon O'Neill from Diabetes UK said: "Much more research needs to be done to justify the use of this drug in preventing type 2 diabetes. We strongly recommend that people at risk of developing type 2 diabetes should be incorporating increased levels of physical activity into their daily lives alongside making changes to their diet." By Michael Day