Intensive Insulin Therapy Increases the Risk of Hypoglycemia in Neurocritical Care Patients

Background: Intensive insulin therapy protocols are widely used in intensive care medicine. A disadvantage of these protocols may be the occurrence of hypoglycemic episodes. Neurocritical care patients are particularly vulnerable to the effects of hypoglycemia. We aimed to study the risk of hypoglycemia in neurocritical care patients in relation to intensive insulin therapy. Methods: To determine the effects of 2 different intensive insulin therapy protocols on glucose levels and hypoglycemia incidence, we collected data before and after implementation of the protocols in 2 university hospitals. The risk of hypoglycemia (blood glucose level below 3.0 mmol/L) was studied retrospectively with logistic regression analyses. Results: In hospital A, data were obtained on 152 patients before implementation of the protocol and on 649 patients after implementation of the protocol. In hospital B, data were obtained on 111 patients before implementation of the protocol and on 118 patients thereafter. Implementation of intensive insulin therapy protocols increased the time spent in the desired blood glucose range of 4.6 to 6.0 mmol/L in both hospitals, but increased the risk of hypoglycemia: the absolute risk of hypoglycemia during intensive care unit admission increased in hospital A from 14.5% to 20.3% (adjusted odds ratio = 1.3; 95% confidence interval: 0.8-2.3) and in hospital B from 3.6% to 29.7% (adjusted odds ratio = 28.6; 95% confidence interval: 5.9-138.9). Conclusions: Implementation of intensive insulin therapy protocols in neurocritical care patients not only seems to increase the time spent in the desired blood glucose range, but also seems to increase the risk of hypoglycemia. The risk of hypoglycemia strongly depends on characteristics of the intensive insulin therapy protocol.