Aggressive Insulin Intensification Required for Severe Hyperglycemia
This patient with insulin resistance, A1C of 16%, and inadequate basal insulin coverage (Lantus 15 units BID = 30 units total daily) requires immediate transition to a proper basal-bolus regimen, not sliding scale insulin. Sliding scale insulin as monotherapy is explicitly condemned by all major diabetes guidelines and shown to be ineffective 1, 2.
Critical Problems with Current Regimen
The current approach is fundamentally flawed. For an A1C of 16%, guidelines recommend starting doses of 0.3-0.5 units/kg/day as total daily insulin 1. If this patient weighs approximately 70 kg, they need 21-35 units/day minimum as basal insulin alone, plus prandial coverage. The current 30 units total is grossly insufficient 1.
Sliding scale insulin treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations 1. With proper basal-bolus therapy at weight-based dosing, 68% of patients achieve mean blood glucose <140 mg/dL versus only 38% with sliding scale alone 1.
Recommended Insulin Regimen
Immediate Basal Insulin Adjustment
Consolidate to once-daily Lantus dosing as FDA-approved dosing for insulin glargine is once daily at the same time each day 1, 3. Start with 0.3-0.4 units/kg/day given the severe hyperglycemia 1.
- For a 70 kg patient: Start Lantus 21-28 units once daily at bedtime 1
- Increase by 4 units every 3 days until fasting glucose reaches 80-130 mg/dL 1
- Target fasting glucose: 80-130 mg/dL 1
Add Prandial Insulin Coverage
Prandial insulin is essential from the outset with A1C this elevated 1. Blood glucose in the 200s mg/dL reflects both inadequate basal coverage AND postprandial excursions requiring mealtime insulin 1.
- Start with 4 units of rapid-acting insulin (lispro, aspart, or glulisine) before each of the three largest meals 1
- Alternatively, use 10% of the basal dose per meal 1
- Administer 0-15 minutes before meals 1, 2
- Titrate by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 1
- Target postprandial glucose: <180 mg/dL 1
Correction Insulin Protocol
Use correction insulin as an adjunct only, not as monotherapy 1:
- Add 2 units of rapid-acting insulin for premeal glucose >250 mg/dL 1
- Add 4 units for premeal glucose >350 mg/dL 1
- Never give rapid-acting insulin at bedtime to avoid nocturnal hypoglycemia 1
Foundation Therapy: Metformin
Metformin must be continued or initiated unless contraindicated 1. The combination of metformin and insulin provides superior glycemic control with reduced insulin requirements and less weight gain compared to insulin alone 1, 2.
- Target dose: 1000 mg twice daily (2000 mg total), up to maximum 2500 mg/day 1
- Continue metformin even when intensifying insulin therapy 1
Monitoring Requirements
Daily fasting blood glucose monitoring is essential during titration 1:
- Check fasting glucose every morning 1
- Check pre-meal glucose before each meal to calculate correction doses 1
- Check 2-hour postprandial glucose to assess prandial insulin adequacy 1
- Reassess every 3 days during active titration 1
- Check A1C every 3 months 1
Expected Outcomes
With appropriate basal-bolus therapy at weight-based dosing, HbA1c reduction of 3-4% is achievable over 3-6 months with no increased hypoglycemia risk when properly implemented 1. This patient should expect A1C to decrease from 16% to approximately 12-13% within 3 months, with continued improvement thereafter 1.
Critical Threshold Monitoring
Watch for overbasalization when basal insulin exceeds 0.5 units/kg/day 1:
- Clinical signals include: basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, high glucose variability 1
- When basal insulin approaches 0.5-1.0 units/kg/day without achieving targets, intensify prandial insulin rather than continuing to escalate basal insulin alone 1
Common Pitfalls to Avoid
Never continue sliding scale as monotherapy, even temporarily 1. Scheduled basal-bolus insulin with correction doses as adjunct only is superior 1.
Never delay insulin intensification in patients not achieving glycemic goals 1. Many months of uncontrolled hyperglycemia should specifically be avoided to prevent long-term complications 1.
Never discontinue metformin when starting or intensifying insulin unless contraindicated, as this leads to higher insulin requirements and more weight gain 1.