What should the Lantus (insulin glargine) dose, carb coverage ratio, and correction scale be for a patient with an A1C of 13.1%, on a D5 IV, receiving insulin drip, with ketones of 0.28 mmol/L, and mild impaired renal function?

Insulin Management for Severe Hyperglycemia with Ketosis

This patient requires immediate intensification of insulin therapy with a basal-bolus regimen given the severe hyperglycemia (A1C 13.1%, glucose 125 mg/dL on D5 infusion), mild ketosis (0.28 mmol/L), and ongoing insulin drip requirement. 1

Immediate Assessment and Context

This 59-year-old male presents with:

• Severe uncontrolled diabetes: A1C 13.1% indicates chronic severe hyperglycemia 1
• Mild ketosis without acidosis: Ketones 0.28 mmol/L with bicarbonate 18 and normal anion gap 11 2
• Current insulin requirements: On insulin drip at 4 units/hour, already received 25 units Lantus
• Significant insulin resistance: BMI 38, weight 103 kg suggests substantial insulin requirements 2

The mild ketosis with preserved bicarbonate indicates this is not DKA, but rather stress ketosis or starvation ketosis in the setting of severe hyperglycemia. 2

Recommended Lantus Dose

Start with 40-50 units of Lantus once daily (0.4-0.5 units/kg/day). 1

Rationale for dosing:

• For severe hyperglycemia (A1C >9%, glucose persistently elevated), guidelines recommend starting doses of 0.3-0.5 units/kg/day 1
• At 103 kg: 0.4 units/kg = 41 units; 0.5 units/kg = 52 units 1
• The patient is already on insulin infusion requiring 4 units/hour (96 units/24 hours), suggesting high insulin requirements 2
• Start with 45 units Lantus once daily as a reasonable middle ground 1

Titration algorithm:

• Increase by 4 units every 3 days if fasting glucose ≥180 mg/dL 1
• Increase by 2 units every 3 days if fasting glucose 140-179 mg/dL 1
• Target fasting glucose: 80-130 mg/dL 1
• If hypoglycemia occurs, reduce dose by 10-20% 1

Carbohydrate Coverage Ratio

Start with 1:8 carb ratio (1 unit per 8 grams of carbohydrate) for all meals. 2, 1

Initial prandial insulin dosing:

• The current 1:8 ratio is appropriate as a starting point 2
• Alternative approach: Start with 4 units of rapid-acting insulin before each meal 2, 1
• For this patient with severe hyperglycemia and high insulin requirements, the 1:8 ratio (more aggressive than 4 units flat) is more appropriate 1

Titration of carb ratio:

• Adjust by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 1
• If postprandial glucose remains >180 mg/dL, tighten ratio to 1:6 or 1:7 1
• Monitor for hypoglycemia and liberalize ratio if needed 1

Correction Scale (Insulin Sensitivity Factor)

Use a correction factor of 1 unit per 30-40 mg/dL above target glucose of 120 mg/dL. 2, 1

Specific correction scale:

• Glucose 121-160 mg/dL: Add 1 unit
• Glucose 161-200 mg/dL: Add 2 units
• Glucose 201-240 mg/dL: Add 3 units
• Glucose 241-280 mg/dL: Add 4 units
• Glucose 281-320 mg/dL: Add 5 units
• Glucose >320 mg/dL: Add 6 units and contact provider 1

This assumes an insulin sensitivity factor of approximately 1:35 (1 unit lowers glucose by 35 mg/dL), which is appropriate for someone with significant insulin resistance (BMI 38). 2

Adjustment of correction scale:

• If glucose remains elevated despite corrections, tighten to 1 unit per 25-30 mg/dL 1
• If frequent hypoglycemia occurs, liberalize to 1 unit per 40-50 mg/dL 1

Critical Management Considerations

Transition from insulin drip:

• Continue insulin drip for 2-4 hours after first Lantus dose to ensure overlap 2
• The 25 units of Lantus already given is insufficient for this patient's needs 1
• Administer the full 45 units of Lantus, not an additional 45 units on top of the 25 already given 1

Foundation therapy:

• Ensure patient is on metformin unless contraindicated (creatinine 0.8 is normal, so no contraindication) 1, 3
• Metformin should be continued even with intensive insulin therapy 1, 3

Monitoring requirements:

• Check fasting glucose daily during titration phase 1
• Check pre-meal and 2-hour postprandial glucose to guide prandial insulin adjustments 1
• Reassess A1C in 3 months 2
• Daily monitoring for hypoglycemia, especially during first 1-2 weeks 1

Common pitfalls to avoid:

• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day (52-103 units for this patient) without adequate prandial coverage—this leads to overbasalization with increased hypoglycemia risk 1, 3
• Do not rely solely on correction insulin—scheduled basal-bolus regimen is essential 1
• Do not delay intensification—with A1C 13.1%, aggressive treatment is needed immediately 1
• Do not wait longer than 3 days between dose adjustments in stable patients 1

Signs of overbasalization to monitor:

• Basal dose >0.5 units/kg/day with persistent hyperglycemia 1
• Bedtime-to-morning glucose differential ≥50 mg/dL 1
• Hypoglycemia episodes 1
• High glucose variability 1

If these occur, add or increase prandial insulin rather than continuing to escalate basal insulin. 1, 3

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

Expected Outcomes

With this regimen (45 units Lantus, 1:8 carb ratio, 1:35 correction factor), expect:

• Fasting glucose to reach 80-130 mg/dL within 1-2 weeks with appropriate titration 1
• A1C reduction of 2-3% over 3 months 1
• Resolution of ketosis within 24-48 hours 2

Reassess in 3-6 months: If A1C remains >7% despite optimized basal-bolus insulin, consider adding GLP-1 receptor agonist to reduce insulin requirements and improve glycemic control. 1, 3