In 2001 Van den Berghe et al reported the results of a randomised controlled trial comparing the mortality of critically ill surgical patients receiving insulin infusions to achieve “tight glycaemic control” (target blood glucose 4.4-6.1 mmol/l) with that of patients receiving conventional treatment, where insulin was infused only if the blood glucose exceeded 11.9 mmol/l and was adjusted to maintain values of 10-11.1 mmol/l.1 The trial was stopped after 1548 patients had been enrolled because the mortality in the tight control group was 4.6% compared with 8% in the control group (32% corrected relative reduction; P = 0.04). Ever since, tight glycaemic control has been standard practice, but there are now good reasons to question it.

It always seemed surprising that a simple change in blood glucose management reduced mortality more than other far more costly and complex interventions tested through randomised trials in the critically ill. The only corroborating evidence came from studies of …