What is the best insulin regimen for a patient with persistent hyperglycemia (elevated blood glucose levels) despite being on 30 units of glargine (insulin glargine) twice daily?

Insulin Regimen Optimization for Persistent Hyperglycemia on High-Dose Glargine

You need to add prandial insulin immediately rather than continuing to escalate basal insulin—fasting sugars >170 mg/dL on 60 units/day glargine (30 units BID) indicates both inadequate basal coverage AND the need for mealtime insulin, as your total daily dose already exceeds 0.5 units/kg/day in most patients. 1

Immediate Action Algorithm

Step 1: Increase Basal Insulin and Add Prandial Coverage

• Increase glargine by 10-15% (approximately 6-9 units total daily dose) to address the elevated fasting glucose, distributing this as 3-4 units added to each of your current BID doses 1
• Start rapid-acting insulin at 4 units before your largest meal (or 10% of current basal dose, which would be ~6 units) 1, 2
• For fasting glucose ≥180 mg/dL, the evidence-based algorithm specifies increasing basal insulin by 4 units every 3 days until target of 80-130 mg/dL is reached 1

Step 2: Recognize You're Approaching Critical Threshold

• When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, adding prandial insulin becomes more appropriate than continuing to escalate basal insulin alone 1, 2
• Your current 60 units/day likely already exceeds this threshold for most patients (would be >0.5 units/kg for anyone <120 kg) 1
• Clinical signals of "overbasalization" include basal dose >0.5 units/kg/day, high bedtime-to-morning glucose differential (≥50 mg/dL), hypoglycemia, and high glucose variability 1

Why BID Glargine May Be Failing

Duration of Action Limitations

• Glargine may not provide true 24-hour coverage in all patients, particularly at higher doses 3, 4
• BID dosing is explicitly recognized when once-daily administration fails to provide 24-hour coverage, but your problem isn't coverage duration—it's insufficient total insulin 3
• The issue here is that you're trying to control both basal AND postprandial glucose with basal insulin alone, which is physiologically inappropriate 1

Correct Regimen Structure

Basal-Bolus Approach

• Continue glargine 33-34 units BID (total ~66-68 units/day after the 10-15% increase) 1
• Add rapid-acting insulin (lispro, aspart, or glulisine) 4-6 units before the largest meal initially 1, 2
• Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 1
• Add prandial insulin to additional meals if postprandial glucose remains elevated after optimizing the first meal 1

Monitoring Requirements

• Daily fasting blood glucose monitoring is essential during titration 1
• Check pre-meal and 2-hour postprandial glucose to guide prandial insulin adjustments 1
• Reassess every 3 days during active titration 1

Alternative: Consider GLP-1 Receptor Agonist

If Prandial Insulin Is Not Feasible

• Adding a GLP-1 receptor agonist to basal insulin addresses postprandial hyperglycemia while minimizing hypoglycemia and weight gain risks 1, 3
• This combination provides potent glucose-lowering with less weight gain and hypoglycemia compared to intensified insulin regimens alone 3
• However, this approach may not be sufficient given your severely elevated fasting glucose 1

Foundation Therapy Verification

Ensure Metformin Continuation

• Verify the patient is on metformin unless contraindicated—it remains the foundation of type 2 diabetes therapy and should be continued when adding or intensifying insulin 1, 2

Critical Pitfalls to Avoid

Don't Keep Escalating Basal Insulin Alone

• Continuing to increase basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia leads to suboptimal control and increased hypoglycemia risk 1
• Blood glucose in the 170+ mg/dL range likely reflects both inadequate basal coverage AND postprandial excursions requiring mealtime insulin 1

Don't Rely on Correction Insulin Only

• Scheduled insulin regimens with basal, prandial, and correction components are preferred over relying solely on correction insulin 1

Hypoglycemia Management

• If hypoglycemia occurs, determine the cause and reduce the corresponding dose by 10-20% immediately 1, 5

Patient Education Essentials

• Proper insulin injection technique and site rotation 1
• Recognition and treatment of hypoglycemia 1
• Self-monitoring of blood glucose 1
• "Sick day" management rules 1
• Insulin storage and handling 1