What should be the starting dose of Lantus (insulin glargine) and the insulin-to-carbohydrate ratio (ICR) and insulin sensitivity factor (ISF) for a male patient with a hemoglobin A1C (HbA1C) level of 11.9%, who weighs 71.4 kg and has a body mass index (BMI) of 23, and has previously been on insulin therapy?

Insulin Regimen for Patient with A1C 11.9%, Weight 71.4 kg, BMI 23

For a male patient with A1C 11.9%, weight 71.4 kg, BMI 23, who previously discontinued insulin therapy, the recommended starting Lantus dose is 14-18 units (0.2-0.25 units/kg) once daily, with an initial insulin-to-carbohydrate ratio (ICR) of 1:10 and insulin sensitivity factor (ISF) of 30-40.

Initial Basal Insulin (Lantus) Dosing

• Given the severely elevated A1C of 11.9%, insulin therapy should be initiated promptly as the patient likely requires the potency of injectable therapy for glucose control 1
• The recommended starting dose for Lantus (insulin glargine) is 0.1-0.2 units/kg/day, which would be approximately 7-14 units for this 71.4 kg patient 1
• However, considering the very high A1C level (>10%), a slightly higher starting dose of 0.2-0.25 units/kg/day (14-18 units) would be more appropriate 1
• The Lantus dose should be administered once daily, preferably at the same time each day 1

Titration Algorithm for Basal Insulin

• After initiating Lantus, implement a structured titration algorithm to reach target fasting blood glucose 1, 2:
  • Increase dose by 2 units every 3 days until fasting blood glucose reaches target (typically 80-130 mg/dL)
  • If any hypoglycemia occurs, reduce the dose by 10-20% 1
• Patient self-titration has shown better outcomes than clinic-based titration in multiple studies 2

Insulin-to-Carbohydrate Ratio (ICR)

• For a patient with this A1C level who previously used insulin, start with an ICR of 1:10 (1 unit of insulin for every 10 grams of carbohydrate) 1
• This ratio is appropriate for initiating prandial insulin coverage in someone with significant hyperglycemia 1
• The ICR may need adjustment based on pre- and post-meal glucose monitoring 1

Insulin Sensitivity Factor (ISF)

• Start with an ISF of 30-40 (1 unit of insulin will lower blood glucose by 30-40 mg/dL) 1
• The ISF can be estimated using the "1800 rule" for regular insulin or the "1700 rule" for rapid-acting insulin: 1700 ÷ Total Daily Dose (TDD) 1
• Since the initial TDD will be approximately 40-50 units (basal plus prandial), the ISF would be approximately 34-42 mg/dL per unit 1

Comprehensive Insulin Management Plan

• Given the high A1C of 11.9%, a basal-bolus regimen is likely necessary rather than basal insulin alone 1
• Start with basal insulin (Lantus) plus prandial insulin with meals 1
• Initial prandial insulin dose should be 4 units per meal or 10% of the basal insulin dose per meal 1
• Monitor blood glucose before meals and at bedtime to guide dose adjustments 1

Monitoring and Adjustment

• Titrate the basal insulin dose based on fasting blood glucose levels 1, 2
• Adjust the ICR based on 2-hour post-meal glucose readings 1
• Adjust the ISF based on correction dose effectiveness 1
• Consider reducing the basal insulin dose by 10% when adding prandial insulin to avoid hypoglycemia 1
• Reassess the regimen every 3-6 months or sooner if glycemic targets are not being met 1

Common Pitfalls to Avoid

• Avoid delaying insulin therapy in patients with A1C >10%, as this can lead to continued hyperglycemia and metabolic decompensation 1, 3
• Do not rely solely on sliding scale insulin without basal coverage, as this approach is ineffective for sustained glycemic control 3
• Be aware that insulin requirements may have changed since the patient was previously on insulin therapy 1
• Recognize that insulin glargine (Lantus) has a lower risk of nocturnal hypoglycemia compared to NPH insulin, which is an important consideration when titrating doses 4, 5