Higher insulin infusion rate but not 24-h insulin consumption is associated with hypoglycemia in critically ill patients.

Aims: To assess the association between insulin infusion rates, and 24-h insulin consumption on hypoglycemia in the intensive care unit (ICU).

Methods: This was a retrospective case-control study, conducted at an academic institution in the United States. Adult patients admitted to the ICU receiving intravenous insulin infusions for blood glucose control were included. Hypoglycemic (blood glucose <70 mg/dL) patients were matched 1:1 with non-hypoglycemic controls based on age, gender, and body mass index. Multivariable conditional logistic regression analyses were conducted to determine the effect of: (1) weight-adjusted insulin infusion rate (units/kg/h), (2) non-weight-adjusted insulin infusion rate (units/h), or (3) 24-h insulin consumption (units/day) on hypoglycemia.

Results: A total of 122 patients were included in the study (61 cases, 61 controls). Compared to those patients who received <0.05 units/kg/h, the odds of hypoglycemia was higher in those who received was ≥0.1 units/kg/h (OR 4.57, 95% CI 1.45-14.41, p=0.010). Compared to those patients who received <4 units/h, the odds of hypoglycemia was higher in those who received was ≥8 units/h (4.17, 95% CI 1.18-14.75, p=0.027). The risk of hypoglycemia did not increase with higher 24-h insulin consumption.

Conclusions: Higher insulin infusion rates rather than 24-h insulin consumption may be associated with hypoglycemia in critically ill patients in the ICU.