Steroid Induced Hyperglycaemia

Steroid induced hyperglycaemia is a rise in glucose caused by glucocorticoids through insulin resistance, reduced insulin secretion and increased hepatic glucose output. With a single morning dose of prednisolone, glucose rises from late morning to evening and fasting glucose is often normal, so fasting checks miss it. It affects people with and without prior diabetes and settles as the dose falls.

Pattern by steroid. - Morning prednisolone, hydrocortisone or methylprednisolone: peak 4 to 8 hours after the dose. - Dexamethasone and divided or long-acting doses: persistent hyperglycaemia including fasting.

Risk factors. Prediabetes, older age, obesity, a prednisolone dose of 20 mg or more, family history of diabetes, and prior gestational diabetes.

Detection. Check capillary glucose before the evening meal and at bedtime from day 1 in high-risk patients, and in anyone on 20 mg or more of prednisolone. Treat when two readings are over 12 mmol/L, or one is over 14 mmol/L.

Morning prednisolone. Isophane insulin given with the steroid dose matches its profile.

Long-acting steroid or divided doses. Basal analogue plus mealtime insulin.

Oral options for mild disease. Gliclazide 40 to 80 mg orally with the morning steroid dose (watch for hypoglycaemia as the steroid wears off), metformin if eGFR allows, and pioglitazone for longer courses.

Avoid. SGLT2 inhibitors during acute illness because of ketoacidosis risk.

Isophane insulin with morning prednisolone. Give subcutaneously with the steroid dose: 0.1 units/kg for each 10 mg of prednisolone, up to 0.4 units/kg at 40 mg or more. Reduce the dose by 25% in older adults, kidney impairment or liver impairment.

Adjustment. Increase the dose by 10 to 20% every 1 to 2 days until pre-evening-meal glucose is 6 to 10 mmol/L.

Existing insulin users. Increase mealtime and correction insulin in the afternoon and evening, and add isophane insulin in the morning if needed.

Tapering the steroid. Reduce the insulin dose by the same percentage as each steroid reduction (about 10 to 20% for each step), and stop insulin when prednisolone is under 10 mg or 7.5 mg daily if glucose stays under 10 mmol/L.

Dexamethasone. Start basal insulin 0.1 to 0.2 units/kg plus mealtime insulin, reviewing daily.

Special groups. - Kidney impairment and liver disease: use the lowest doses and avoid sulphonylureas. - Pregnancy: antenatal steroids need insulin increases for 3 days. - Older adults: halve starting doses and monitor for hypoglycaemia at night. - Children: weight-based insulin with specialist care.

Monitoring. Capillary glucose before meals and at bedtime for as long as steroids are given, and for 48 hours after stopping. Glucose may remain high for days after high-dose pulses.

After steroids stop. Repeat HbA1c and fasting glucose at 3 months in anyone who needed treatment, because underlying diabetes may be unmasked.

Stopping. Stop the glucose lowering drug when the steroid has stopped and glucose is under target without treatment.

Referral and escalation. Refer for glucose over 20 mmol/L, ketones, osmolality signs of hyperosmolar state, or insulin needs over 1 unit/kg.