Last Modified: 1:28pm 16/04/2021

What is Hyperglycaemia?

Patients with newly discovered hyperglycaemia have significantly higher in-hospital mortality than patients with a known history of diabetes or normoglycaemic patients.

Increasing evidence indicates that the development of hyperglycaemia during acute medical or surgical illness is not a physiological or benign condition, but is a marker of poor clinical outcome and mortality.

Both hyperglycaemia and hypoglycaemia are associated with higher mortality, independent of known history of diabetes.

BMJ Best Practice 2021

Hyperglycemia means there is too much sugar in a patients bloodstream.

It has been defined by the World Health Organisation as:

  • Blood glucose levels greater than 7.0 mmol/L (126 mg/dl) when fasting
  • Blood glucose levels greater than 11.0 mmol/L (200 mg/dl) 2 hours after meals

Although blood sugar levels exceeding 7 mmol/L for extended periods of time can start to cause damage to internal organs, symptoms may not develop until blood glucose levels exceed 11 mmol/L.

Hyperglycemia should not be confused with hypoglycaemia which is when blood sugar levels go too low.

Aetiology of inpatient hyperglycaemia.

Multi-factorial and involves increases in circulating concentrations of stress hormones, along with possible deleterious effects on vascular, haemodynamic, and immune systems.

Concomitant treatments often exacerbate the problem. Corticosteroid therapy that induces insulin resistance is a good example. In addition, parenteral nutrition with a high fat load leads to increased free fatty acids, which in turn affect glucose metabolism.

Hyperglycaemia has multiple consequences, which may affect clinical outcomes. These include altered white blood cell function, blood flow and reactivity, and oxidative stress. Thus, correction of hyperglycaemia is theoretically appealing.

BMJ Best Practice 2021