Beyond diabetes: saving lives with insulin in the ICU

Abstract

The risk of mortality or significant moridity is high among long-stay intensive care unit (ICU) patients. Sepsis, polyneuropathy and multiple organ failure are prominent causes of mortality and morbidity in the ICU. Many ICU patients are hyperglycaemic, presumably reflecting an adaptive development of insulin resistance. We hypothesized that this hyperglycaemia predisposes patients to many of the typical ICU complications, prolonged intensive care dependence and excess mortality. Insulin therapy directed at establishing normoglycaemia was investigated in a series of 1548 ICU patients. An intensive treatment group received insulin infusion tailored to control blood glucose levels in the range 4.4–6.1 mmol/l (80–110 mg/dl), whereas the conventional treatment group only received insulin when glucose levels exceeded 11.1 mmol/l (200 mg/dl) and in that event were maintained in a target range of 10.0–11.1 mmol/l (180–200 mg/dl). Intensive management of blood glucose levels was reflected in a 43% reduction in intensive care mortality risk (P=0.036 after correction for interim analyses) and a 34% reduction in hospital mortality (P=0.01). A reduced risk of infection was reflected in a 46% reduction in the risk of septicaemia (P=0.003) and a 35% reduction in the need for prolonged (>10 d) antibiotic therapy (P<0.001). Regression analysis suggests that control of glucose levels, rather than insulin administration itself, was responsible for the clinical benefits observed. Use of insulin infusion to control glucose levels in ICU patients, at least in populations similar to those in our study, can be expected to achieve clinically welcome improvements in outcome. An algorithm is proposed for implementing this. Further data are needed to establish the applicability of this strategy to other patient groups in the ICU and in general hospital care.