Metabolic inefficacy of a short-term low-dose insulin regimen in critically ill patients: a randomized, placebo-controlled trial.

OBJECTIVE

Hyperglycemia and protein catabolism frequently occur in critically ill patients and both are associated with increased complication rates. These metabolic alterations can be improved by insulin administered exogenously. Since a wide range of insulin dosages have been used, this randomized, placebo-controlled, investigator-blinded, clinical study tests the hypothesis that a low-dose insulin regimen improves hyperglycemia and protein catabolism in critically ill medical patients.

PATIENTS AND METHODS

The day after their admission to a medical intensive care unit, forty consecutive, critically ill medical patients were randomized for receiving either a low-dose insulin regimen (i.e. 1 IU/h) (treatment group, n = 20) or placebo (control group, n = 20) continuously over 24 hours. The primary endpoint was the efficacy of the low-dose insulin regimen to decrease serum glucose concentrations; the secondary endpoint was its influence on protein catabolism. Serum glucose concentrations and protein catabolism, which was assessed by the urea nitrogen appearance rate, were determined at baseline and at 8 and 24 hours thereafter. Serum insulin concentrations were measured at baseline and after 24 hours.

RESULTS

After 24 hours the low-dose insulin regimen increased serum insulin concentrations compared with baseline (16.8+/-13.3 microU/ml and 11.5+/-16.9 microU/ml, respectively; p<0.05). Hyperglycemia and the urea nitrogen appearance rate did not change within the two groups of patients and there was no difference between the groups at the different time points.

CONCLUSIONS

Administration of the low-dose insulin regimen was safe. However, the short-term low-dose insulin regimen was inefficient in influencing mild hyperglycemia and protein catabolism in critically ill medical patients.