Should insulin be initiated in a patient with hyperglycemia (elevated blood sugar levels) who is currently on steroid therapy?

Management of Steroid-Induced Hyperglycemia with Insulin

Yes, you should initiate insulin therapy for a patient with hyperglycemia on steroids, as insulin is the preferred and most effective treatment for steroid-induced hyperglycemia. 1, 2

Why Insulin is Essential

Oral antidiabetic agents alone are insufficient for managing hyperglycemia in patients on high-dose steroid therapy. 2 The hyperglycemic effect of steroids is too pronounced to be adequately controlled with oral medications, particularly when patients are on supraphysiological doses. 3

Understanding the Hyperglycemic Pattern

Before initiating therapy, recognize that steroid-induced hyperglycemia follows a predictable pattern:

• Peak hyperglycemia occurs 6-9 hours after morning steroid administration, typically in the afternoon and evening 1, 2
• Glucose levels often normalize overnight even without treatment 2
• The degree of hyperglycemia directly correlates with steroid dose—higher doses cause more significant elevations 2
• Do not rely on fasting glucose alone, as this will miss the peak hyperglycemic effect occurring in the afternoon 1, 2

Insulin Selection and Dosing

For Moderate Hyperglycemia (Glucose <400 mg/dL)

NPH insulin is the preferred agent because its 4-6 hour peak action aligns perfectly with the 6-9 hour peak hyperglycemic effect of morning glucocorticoid doses. 1, 2 This is superior to long-acting basal insulins like glargine, which lack the appropriate peak to match steroid-induced hyperglycemia patterns. 4

Starting dose:

• 0.3-0.5 units/kg/day given as a single morning dose (or 3 hours after steroid administration) 1, 2
• For higher steroid doses (prednisone ≥50 mg), consider starting at 0.5 units/kg/day 1
• For patients with higher baseline HbA1c or pre-existing diabetes, may need 40-60% increase above baseline 2

Alternative option:

• Mixtard (premixed insulin 30/70) can be used at 0.3-0.5 units/kg/day given in the morning 1
• However, this lacks flexibility to independently adjust basal and prandial components 5

For Severe Hyperglycemia (Glucose >400-500 mg/dL)

Continuous intravenous insulin infusion is the preferred regimen for severe steroid-induced hyperglycemia. 6, 5 This represents Grade 4 toxicity requiring:

• Hospital admission for IV insulin therapy 5
• Volume resuscitation 5
• Evaluation for diabetic ketoacidosis or hyperosmolar hyperglycemic state 5
• Target glucose 140-180 mg/dL (7.8-10.0 mmol/L) 6, 5

Once stable, transition to basal-bolus subcutaneous insulin:

• NPH insulin 0.3-0.5 units/kg given in the morning PLUS rapid-acting insulin before meals 1
• This provides superior control compared to NPH alone for severe cases 1

Monitoring Protocol

Implement four-times-daily glucose monitoring: fasting and 2 hours after each meal. 1, 2 This is critical because:

• Fasting glucose alone misses the peak hyperglycemic effect 1, 2
• Afternoon/evening readings are most important for dose adjustments 2
• Target range: 100-180 mg/dL (5.6-10.0 mmol/L) 1

Dose Adjustment Strategy

As steroids are tapered, insulin doses must be proportionally decreased by the same percentage as the steroid dose reduction to prevent hypoglycemia. 1, 2, 5 This is a critical and commonly missed step.

• Increase NPH by 10-20% (3-5 units) every 2-3 days if afternoon glucose remains elevated 1
• Insulin requirements can decline rapidly after steroid discontinuation 5
• Adjust based on afternoon/evening glucose patterns, not fasting values 2

Critical Pitfalls to Avoid

Common errors that lead to poor outcomes:

1. Holding steroids instead of treating hyperglycemia—this denies patients necessary anti-inflammatory therapy for a treatable complication 5
2. Using only sliding-scale correction insulin without scheduled insulin—this leads to poor glycemic control 5
3. Failing to reduce insulin when steroids are tapered—this causes hypoglycemia 1, 2, 5
4. Relying on fasting glucose for monitoring—this misses the peak effect 1, 2

Special Considerations

For nighttime steroid dosing:

• Switch from morning NPH to long-acting basal insulin (glargine) given at bedtime 1

For elderly or renally impaired patients:

• Start with lower doses (0.2-0.3 units/kg/day) 1

Adjunctive therapy:

• Metformin can be added in patients with preserved renal and hepatic function, with some evidence it alleviates metabolic effects of steroids 6, 2
• However, metformin alone is insufficient as primary therapy 2

Emergency Warning Signs

Warn patients that hyperosmolar hyperglycemic state can develop in very severe cases. 6, 2 Patients should present to the hospital immediately if:

• Capillary blood glucose persistently above 20 mmol/L (360 mg/dL) despite treatment 6, 2
• Glucose meter reading "HI" 6

Patient Education Requirements

Provide comprehensive education on: 6, 2

• Glucose monitoring technique and frequency (four times daily)
• Symptoms of severe hyperglycemia and emergency thresholds
• Symptoms of hypoglycemia as insulin is initiated
• Emphasize that adjustments to steroids necessitate review of insulin doses 6