Hypoglycemia and Risk of Death in Critically Ill Patients
What is the impact of hypoglycemia on mortality in critically ill patients?
The investigators examined the associations between moderate and severe hypoglycemia (blood glucose, 41-70 mg/dl [2.3-3.9 mmol/L] and ≤40 mg/dl [2.2 mmol/L], respectively) and death among 6,026 critically ill patients in intensive care units (ICUs). Patients were randomly assigned to intensive or conventional glucose control. They used Cox regression analysis with adjustment for treatment assignment and for baseline and post-randomization covariates.
Follow-up data were available for 6,026 patients: 2,714 (45.0%) had moderate hypoglycemia, 2,237 (82.4%) of whom were in the intensive-control group (i.e., 74.2% of the 3,013 patients in the group), and 223 patients (3.7%) had severe hypoglycemia, 208 (93.3%) of whom were in the intensive-control group (i.e., 6.9% of the patients in this group). Of the 3,089 patients who did not have hypoglycemia, 726 (23.5%) died, as compared with 774 of the 2,714 with moderate hypoglycemia (28.5%) and 79 of the 223 with severe hypoglycemia (35.4%). The adjusted hazard ratios for death among patients with moderate or severe hypoglycemia, as compared with those without hypoglycemia, were 1.41 (95% confidence interval [CI], 1.21-1.62; p < 0.001) and 2.10 (95% CI, 1.59-2.77; p < 0.001), respectively. The association with death was increased among patients who had moderate hypoglycemia on more than 1 day (>1 day vs. 1 day, p = 0.01), those who died from distributive (vasodilated) shock (p < 0.001), and those who had severe hypoglycemia in the absence of insulin treatment (hazard ratio, 3.84; 95% CI, 2.37-6.23; p < 0.001).
The authors concluded that in critically ill patients, intensive glucose control leads to moderate and severe hypoglycemia, both of which are associated with an increased risk of death.
This study reports that among critically ill patients, moderate and severe hypoglycemia are both strongly associated with an increased risk of death, and that the risk is greater among patients who have severe hypoglycemia. It seems prudent to ensure that strategies for managing the blood glucose concentration in critically ill patients focus not only on the control of hyperglycemia, but also on avoidance of both moderate and severe hypoglycemia. The current recommendation of the American Diabetes Association suggests a target blood glucose concentration of 144-180 mg/dl, and will help reduce the risk of hypoglycemia in critically ill patients.
Keywords: Incidence, Risk, Insulin, Follow-Up Studies, Blood Glucose, Cardiology, Cardiovascular Diseases, Critical Illness, Hypoglycemia, Diabetes Mellitus, United States
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