Screening for hyperglycaemia in patients taking glucocorticoids

Patients at high risk of developing diabetes should ideally be screened for diabetes before starting a glucocorticoid, and have their blood glucose concentration checked soon after starting the glucocorticoid. For information on high-risk patients and the AUSDRISK screening tool, see Screening for type 2 diabetes in asymptomatic adults.

When screening for hyperglycaemia in a patient taking high-dose glucocorticoids, measure either postprandial blood glucose concentrations (2 hours after lunch or the evening meal) or a random afternoon blood glucose concentration. When an oral glucocorticoid is taken in the morning, blood glucose concentrations rise progressively during the day and then fall slowly overnight. Therefore, do not use a fasting blood glucose concentration to screen for glucocorticoid-induced hyperglycaemia; glucocorticoids are more likely to cause postprandial hyperglycaemia. A glycated haemoglobin (HbA1c) test is not suitable to detect short-term glucocorticoid-induced hyperglycaemia.

Glucocorticoid-induced hyperglycaemia is diagnosed if the postprandial blood glucose concentration is 11.1 mmol/L or more on two separate occasions.

When screening for hyperglycaemia in a patient taking a long-term course of low-dose glucocorticoid, consider performing an oral glucose tolerance test or HbA1c test as fasting blood glucose concentration may not be elevated (see Management of patients taking long-term low-dose glucocorticoids). However, an HbA1c will only reflect hyperglycaemia if blood glucose concentrations have been elevated for at least 2 to 3 months.

After the glucocorticoid is stopped, patients with glucocorticoid-induced hyperglycaemia should have definitive testing for diabetes. Even if the patient’s blood glucose concentrations have reduced to normal, they are at greater risk for developing diabetes.