What is the best management approach for an adult patient with type 2 diabetes (T2D) on prednisone (corticosteroid) 30 mg, receiving 34 units of NPH (Neutral Protamine Hagedorn) insulin and requiring 20 units of short-acting insulin, with elevated blood glucose (hyperglycemia) readings of 267 and 391?

Management of Steroid-Induced Hyperglycemia in Type 2 Diabetes

Immediate Insulin Dose Adjustment

Increase your NPH insulin immediately to approximately 50-60 units once daily in the morning (matching the timing of prednisone administration), and add 10-15 units of short-acting insulin before lunch and dinner. 1

Your current regimen of 34 units NPH with 20 units of short-acting insulin is insufficient for blood glucose readings of 267 and 391 mg/dL while on prednisone 30 mg daily. The American Diabetes Association guidelines specifically address this scenario: intermediate-acting glucocorticoids like prednisone cause disproportionate daytime hyperglycemia, and NPH insulin administered concomitantly with morning steroids is the standard approach because NPH peaks at 4-6 hours, matching prednisone's peak plasma levels. 1

Understanding Steroid-Induced Hyperglycemia Patterns

• Prednisone reaches peak plasma levels in 4-6 hours but has pharmacologic actions lasting through the day, causing predominantly daytime hyperglycemia with near-normal overnight glucose levels. 1

• For higher doses of glucocorticoids like your 30 mg prednisone, increasing doses of prandial and correctional insulin by 40-60% or more are often needed in addition to basal insulin. 1

• Glucocorticoids induce hyperglycemia in 56-86% of hospitalized patients with and without preexisting diabetes, and untreated hyperglycemia increases mortality and morbidity risk including infections and cardiovascular events. 1

Specific Dosing Algorithm for Your Situation

Morning dose (with prednisone):

• Increase NPH to 50-60 units (approximately 1.5-1.8 times your current 34 units). 1
• This matches the timing of intermediate-acting steroid administration as recommended. 1

Mealtime coverage:

• Add 10-15 units of short-acting insulin before lunch (when steroid effect peaks). 1
• Add 10-15 units of short-acting insulin before dinner. 1
• Continue correctional insulin every 4-6 hours as needed for blood glucose >180 mg/dL. 1

Target blood glucose:

• Fasting: 80-130 mg/dL 1
• Pre-meal and bedtime: 80-180 mg/dL 1

Critical Monitoring and Adjustment Requirements

• Check blood glucose before each meal and at bedtime daily during steroid therapy. 1

• Make daily adjustments based on glycemia levels and anticipated changes in steroid doses—this is critical to reducing rates of hypoglycemia and hyperglycemia. 1

• If blood glucose remains >180 mg/dL despite these adjustments, increase NPH by 4 units every 3 days and increase prandial insulin by 2-4 units before the meal with highest postprandial readings. 1, 2

Evidence Supporting NPH Over Long-Acting Insulin for Steroids

A retrospective study comparing NPH versus glargine in prednisone-treated hospitalized patients found that NPH required lower total daily insulin doses (0.27 units/kg vs 0.34 units/kg for basal insulin) while achieving similar glycemic control, suggesting NPH's pharmacokinetic profile better matches prednisone's daytime hyperglycemic effect. 3

Common Pitfalls to Avoid

• Do not rely solely on correctional (sliding scale) insulin—scheduled basal-bolus regimens are superior to sliding scale monotherapy and explicitly recommended over reactive correction-only approaches. 1, 2

• Do not wait for glucose to normalize before adjusting doses—daily adjustments are essential during glucocorticoid therapy because steroid doses and effects change rapidly. 1

• Do not reduce insulin doses prematurely—if prednisone is tapered or discontinued, reduce insulin doses by 25-50% immediately to prevent hypoglycemia, but monitor closely as hyperglycemia may persist for 24-48 hours after steroid discontinuation. 1

• Do not forget overnight monitoring initially—while prednisone typically causes daytime hyperglycemia, check overnight glucose (2-3 AM) for the first few nights to ensure NPH isn't causing nocturnal hypoglycemia. 1

Foundation Therapy Considerations

• Continue metformin unless contraindicated, as it provides complementary glucose-lowering effects and reduces total insulin requirements. 2, 4

• Consider adding a GLP-1 receptor agonist if not already prescribed, as combination basal insulin plus GLP-1 RA provides potent glucose-lowering with less hypoglycemia and weight gain than intensified insulin regimens. 2

When to Reassess the Regimen

• If basal insulin exceeds 0.5 units/kg/day (approximately 40-50 units for an average adult) and glucose remains elevated, this signals the need for more aggressive prandial coverage rather than further basal insulin escalation. 1, 2

• After prednisone is discontinued, expect insulin requirements to decrease by 50-75% within 24-48 hours—proactively reduce doses to prevent hypoglycemia. 1