From April 2009 the quality and outcomes framework (QOF) - the system that rewards UK general practices for delivering quality care - will require general practitioners to lower blood glucose levels in half of their patients with type 2 diabetes to below 7% to earn the same amount that they are currently paid for achieving a target of 7.5%.
The average practice that achieves this level of performance will be paid around £3000 (€3375; $4250), write Richard Lehman, a general practitioner in Oxfordshire, and Harlan Krumholz, Professor of Medicine at Yale University School of Medicine.
As a result, tens of thousands of patients will need to be given additional oral treatment or will be treated with insulin, they warn.
Treatment with insulin brings with it an increased risk of hypoglycaemia (when blood glucose levels drop below normal and brain function is affected) and the additional costs of daily blood glucose monitoring and the insulin itself, they explain. It may also result in people who drive for a living losing their job if the new target leads them to be treated with insulin.
This new target was agreed on by NHS employers and the general practitioners' committee of the British Medical Association (BMA) in October 2008, ironically just when evidence was gathering that tight glucose control in established type 2 diabetes has little benefit and can even be harmful.
For example, three important trials published during the past year show that intensive blood glucose control in patients with long standing type 2 diabetes does not provide substantial benefit and may increase the risk of adverse outcomes.
The idea that tight glycaemic control for everyone would improve outcomes was a hypothesis that needed to be tested 30 years ago, say the authors, but in the wake of the three recent studies, it is certainly "time to challenge conventional wisdom."
"We need better evidence to evaluate the balance of risk and benefit for individual patients, and we need to move away from the simplistic idea that the value of a particular drug or strategy can be predicted by its glycaemic lowering effects," they write.
The QOF in the UK has been a successful driver of evidence based improvement in the care of diabetes, particularly tight control of blood pressure and the prescription of cholesterol lowering drugs (statins). But by encouraging tighter glycaemic control in all patients with type 2 diabetes, regardless of disease duration and the drugs used to achieve control, the new QOF target encourages an outdated strategy and one that may not provide a net benefit to patients, they argue.
They believe the change of target from 7.5% to 7% should be withdrawn before it wastes resources and possibly harms patients.
"Editorial: Tight control of blood glucose in long standing type 2 diabetes."
BMJ online
BMJ online