Doctors should be cautious about prescribing intensive glucose lowering treatment for patients with type 2 diabetes as a way of reducing heart complications, concludes a new study published on bmj.com today.
French researchers found that intensive glucose lowering treatment, which is widely used for people with type 2 diabetes to reduce their heightened risk of cardiovascular disease, showed no benefit on all-cause or cardiovascular mortality.
Globally, there were an estimated 150 million adults with diabetes in 2000 and this is expected to rise to 366 million by 2030. People with type 2 diabetes are twice as likely to have cardiovascular disease than non-diabetics and are also more at risk of microvascular complications (damage to small blood vessels).
Glycaemic lowering therapies are commonly used to treat people with type 2 diabetes to prevent long term cardiovascular complications and renal and visual impairment, but previous studies have not shown clear and universal benefits of the treatment.
So a team, led by Catherine Cornu at the Louis Pradel Hospital in Bron, France, reviewed studies that looked at microvascular complications and cardiovascular events related to the intensity of glycaemic control and the quality of trials.
They analysed 13 studies involving 34,533 patients of whom 18,315 were given intensive glucose lowering treatment and 16,218 given standard treatment.
They found that intensive glucose treatment did not significantly affect all-cause mortality or cardiovascular death.
There was, however, a 15% reduction in the risk of non-fatal heart attacks, following intensive treatment and a 10% reduction in microalbuminuria - an indication of kidney problems and heart disease - but a more than two-fold increase in the risk of severe hypoglycaemia (dangerously low blood glucose levels).
The researchers calculated that over a five-year treatment period, 117 to 150 patients would need to be treated to avoid one heart attack, 32 to 142 to avoid one case of microalbuminuria, and 15 to 52 to avoid one severe hypoglycaemic event.
They conclude: "Intensive glucose lowering treatment of type 2 diabetes should be considered with caution and therapeutic escalation should be limited."
In an accompanying editorial, UK experts state that clinicians should consider the absolute risks and benefits of more intensive therapy carefully on an individual patient basis to determine the most sensible treatment strategy.