Risk factors for hypoglycaemia in neurocritical care patients

Purpose

To identify risk factors for hypoglycaemia in neurocritical care patients receiving intensive insulin therapy (IIT).

Methods

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.

Results

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).

Conclusion

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.