Evaluation of short-term consequences of hypoglycemia in an intensive care unit

Introduction of strict glycemic control has increased the risk for hypoglycemia in the intensive care unit. Little is known about the consequences of hypoglycemia in this setting. We examined short-term consequences (seizures, coma, and death) of hypoglycemia in the intensive care unit.

All occurrences of hypoglycemia (glucose of <45 mg/dL) in our intensive care unit between September 1, 2002, and September 1, 2004, were identified. Patients with hypoglycemia (n = 156) were matched for time to hypoglycemia with control patients drawn from the at-risk population (nested case control method). Seizures observed within 8 hrs after hypoglycemia were scored. Discharge summaries for cases and controls were reviewed for occurrence of possible hypoglycemia-associated coma and death. A hazard ratio for in-hospital death was calculated with Cox regression analysis.

The hazard ratio for in-hospital death was 1.03 (95% confidence interval, 0.68-1.56; p = .88) in patients with a first occurrence of hypoglycemia relative to the controls without hypoglycemia, corrected for duration of intensive care unit admittance before hypoglycemia, age, sex, and Acute Physiology and Chronic Health Evaluation II score at admission. No cases of hypoglycemia-associated death were reported. Hypoglycemic coma was reported in two patients. Seizures after hypoglycemia were observed in one patient.

In this study, no association between incidental hypoglycemia and mortality was found. However, this data set is too small to definitely exclude the possibility that hypoglycemia is associated with intensive care unit mortality. In three patients with possible hypoglycemia-associated coma or seizures, a causal role for hypoglycemia seemed likely but could not fully be established.