Risk factors for hypoglycaemia in neurocritical care patients

To identify risk factors for hypoglycaemia in neurocritical care patients receiving intensive insulin therapy (IIT). We performed a nested case-control study. All first episodes of hypoglycaemia (glucose < 80 mg/dL, < 4.4 mmol/L) in neurocritical care patients between 1 March 2006 and 31 December 2007 were identified. Patients were treated according to the local IIT protocol, with target blood glucose levels between 4.5 and 6.0 mmol/L (81.0-108.0 mg/dL). The first hypoglycaemic event of every patient (index moment) was used to match to a control patient. Possible risk factors preceding the index moment were scored using hospital records and analysed with conditional logistic regression. Of 786 neurocritical care patients, 449 developed hypoglycaemia (57.1 %). Independent risk factors for hypoglycaemia were lowering nutrition 6 h before the index moment without insulin dose reduction (odds ratio (OR) 5.25, 95 % confidence interval (95 % CI) 1.32-20.88), mechanical ventilation (OR 2.59, 95 % CI 1.56-4.29), lowering the dosage of norepinephrine 3 h before the index moment (OR 2.44, 95 % CI 1.07-5.55), a hyperglycaemic event (> 10 mmol/L, > 180.0 mg/dL) in the 24 h preceding the index moment (OR 2.40, 95 % CI 1.26-4.58), gastric residual in the 6 h preceding the index moment without insulin dose reduction (OR 1.76, 95 % CI 1.05-2.96) and dosage of insulin at the index moment (OR 0.83, 95 % CI 0.76-0.90). Hypoglycaemia occurs in a considerable proportion of neurocritical care patients. We recommend the identification of these risk factors in these patients to avoid the occurrence of hypoglycaemia.