How should I manage steroid‑induced hyperglycaemia in a patient receiving systemic glucocorticoids (prednisone ≥10 mg/day) with fasting glucose ≥126 mg/dL or 2‑hour post‑prandial glucose ≥200 mg/dL?

Management of Steroid-Induced Hyperglycemia

For patients on prednisone ≥10 mg/day with confirmed hyperglycemia (fasting glucose ≥126 mg/dL or 2-hour post-prandial ≥200 mg/dL), initiate NPH insulin at 0.3-0.5 units/kg/day given in the morning simultaneously with the steroid dose to match the pharmacokinetic profile of glucocorticoid-induced hyperglycemia. 1

Diagnostic Confirmation

• Confirm steroid-induced diabetes with two abnormal tests: random blood glucose ≥11.1 mmol/L (≥200 mg/dL) on different occasions and/or newly elevated HbA1c ≥6.5% in the context of corticosteroid use 2
• The diagnosis is straightforward when persistent hyperglycemia coincides with glucocorticoid therapy 2

Understanding the Hyperglycemic Pattern

• Prednisone administered in the morning produces peak hyperglycemia approximately 8 hours after dosing, corresponding to late morning and afternoon elevations 2, 1
• Blood glucose typically normalizes overnight even without treatment, creating a characteristic diurnal pattern 1
• The degree of hyperglycemia directly correlates with steroid dose—higher doses cause more significant elevations 2, 1, 3

Initial Insulin Therapy

Starting NPH Insulin:

• Begin NPH insulin at 0.3-0.5 units/kg/day administered in the morning with the steroid dose 1
• NPH peaks 4-6 hours after administration, aligning perfectly with the steroid's peak hyperglycemic effect 1
• For patients on high-dose steroids (prednisone >40 mg/day), increase the insulin dose by 40-60% above the initial dose 1
• For elderly or renally impaired patients, start at the lower end (0.2-0.3 units/kg/day) 1

When NPH Alone Is Insufficient:

• For very high steroid doses (>80 mg prednisone equivalent), add prandial rapid-acting insulin before meals, increasing doses by 40-60% or more above baseline 1
• Consider early endocrinology consultation for patients requiring "extraordinary amounts" of insulin 1

Monitoring Protocol

Critical Monitoring Points:

• Check blood glucose four times daily: fasting and 2 hours after each meal 1
• The most important reading is 2 hours after lunch (around 2-3 PM), which captures the peak steroid effect 1
• Target blood glucose range: 90-180 mg/dL (5-10 mmol/L) 1
• Monitor for overnight hypoglycemia, as steroids often cause glucose to normalize at night 1

Insulin Dose Adjustments

Titration Strategy:

• Increase NPH by 2 units every 3 days if target glucose not achieved 1
• Adjust insulin doses based on afternoon and evening glucose patterns, not fasting values alone 1
• As steroid doses are reduced, proportionally decrease insulin doses to prevent hypoglycemia 1
• Adjustments to steroid doses must trigger immediate review of the diabetes treatment regimen 2

Special Scenarios

Long-Acting Glucocorticoids (Dexamethasone):

• Combine long-acting basal insulin (glargine or detemir) with NPH insulin, as dexamethasone affects both fasting and post-prandial glucose 1
• Long-acting basal insulin alone lacks sufficient coverage for the peak hyperglycemic effect 1

Nighttime Prednisone Dosing:

• Switch from NPH to long-acting basal insulin (glargine or detemir) given at bedtime when prednisone is taken at night 1
• The hyperglycemic pattern shifts to overnight and the following day, requiring different insulin coverage 1

Multiple Daily Steroid Doses:

• Use long-acting basal insulin to control fasting glucose, as continuous steroid exposure eliminates the overnight normalization 1
• Multiple daily doses increase risk of severe hyperglycemia (>500 mg/dL) 1

Role of Oral Agents

• Metformin can be added as adjunctive therapy in patients with preserved renal and hepatic function, as it may alleviate some metabolic effects of steroids 2
• Sulfonylureas can be considered for isolated daytime hyperglycemia, though patients must be warned about hypoglycemia risk 2
• Oral agents alone are inadequate for high-dose steroid therapy and should not be relied upon as monotherapy 1

Patient Education Requirements

Essential Education Points:

• Teach glucose monitoring technique and interpretation 2
• Explain symptoms of severe hyperglycemia and safety thresholds for hospital presentation 2
• Warn that glucose levels >360 mg/dL (>20 mmol/L) or meter reading "HI" requires immediate hospital evaluation for hyperosmolar hyperglycemic state 1
• Emphasize that insulin doses will need frequent adjustment as steroid doses change 1
• For patients on hypoglycemia-inducing agents, provide hypoglycemia management education 2

Common Pitfalls to Avoid

Critical Errors:

• Relying on fasting glucose alone will miss the peak hyperglycemic effect and underestimate severity 1
• Failing to anticipate the diurnal pattern with peak effects in afternoon and evening 1
• Not reducing insulin doses when steroids are tapered, leading to dangerous hypoglycemia 1
• Using only sliding-scale correction insulin, which is associated with poor glycemic control 1
• Waiting for fasting hyperglycemia before treating leads to delayed intervention 1

Severe Hyperglycemia Management

• Patients with persistent glucose >360 mg/dL (>20 mmol/L) require hospital admission for continuous IV insulin infusion rather than subcutaneous insulin 1
• Monitor for hyperosmolar hyperglycemic state, a life-threatening complication 1

Steroid Tapering and Transition

• Glucovigilance is required during steroid taper, with insulin dosage reduced proportionally 4
• Frequent reassessment is necessary as steroid doses decrease to prevent hypoglycemia 1
• Some patients may be able to discontinue insulin entirely once steroids are stopped, depending on baseline glucose tolerance 5