Next Step in Decreasing A1C in Type 1 Diabetes on Lantus
Add prandial (mealtime) insulin coverage with rapid-acting insulin analogs before meals, as basal insulin alone is insufficient for optimal glycemic control in type 1 diabetes. 1
Why Basal-Only Therapy is Inadequate for Type 1 Diabetes
Type 1 diabetes requires both basal and prandial insulin components to achieve glycemic targets. 1 The landmark DCCT demonstrated that intensive insulin therapy with multiple daily injections (3-4 injections per day of basal and prandial insulin) reduced A1C and led to 50% reductions in microvascular complications. 1
Your patient on Lantus alone is missing the critical prandial component needed to control postprandial glucose excursions. 1
Recommended Insulin Regimen Structure
Calculate Total Daily Insulin Dose
- Start with 0.5 units/kg/day as total daily insulin dose for metabolically stable type 1 diabetes patients 1
- Divide this 50% as basal insulin (Lantus) and 50% as prandial insulin split among three meals 1
- Higher doses (0.4-1.0 units/kg/day) may be needed during puberty, pregnancy, or illness 1
Add Rapid-Acting Insulin Analogs
- Use rapid-acting insulin analogs (lispro, aspart, or glulisine) before each meal 1
- These analogs have quicker onset and peak with shorter duration than regular human insulin 1
- In type 1 diabetes, analog insulins are associated with less hypoglycemia and weight gain compared to human insulins 1
Insulin-to-Carbohydrate Ratio
- Educate the patient to match prandial insulin dose to carbohydrate intake, premeal blood glucose, and anticipated activity 1
- Calculate carbohydrate-to-insulin ratio (CIR) using the formula: 450 ÷ Total Daily Dose 1
- A typical starting ratio is 1 unit per 10-15 grams of carbohydrate 1
Correction Factor
- Calculate insulin sensitivity factor (ISF) using: 1500 ÷ Total Daily Dose 1
- This determines how much 1 unit of insulin will lower blood glucose 1
Advanced Therapy Options to Consider
Continuous Glucose Monitoring (CGM)
- CGM is now considered standard of care for most people with type 1 diabetes 1
- CGM use reduces nocturnal hypoglycemia and improves overall glycemic control 1
Insulin Pump Therapy (CSII)
- A systematic review concluded that CSII has modest advantages for lowering A1C (0.30% reduction) and reducing severe hypoglycemia rates 1
- Consider pump therapy if multiple daily injections fail to achieve targets 1
Hybrid Closed-Loop Systems
- FDA-approved automated insulin delivery systems are superior to sensor-augmented pump therapy for glycemic control 1
- These systems reduce hypoglycemia over 3 months compared to standard pump therapy 1
Critical Pitfalls to Avoid
Never continue basal insulin alone in type 1 diabetes expecting adequate A1C reduction. 1 Type 1 diabetes is characterized by absolute insulin deficiency requiring both basal and prandial coverage from the outset. 1
Do not delay adding prandial insulin. The DCCT showed that intensive therapy (basal plus prandial) was associated with 50% reductions in microvascular complications, though it did increase severe hypoglycemia risk (62 vs 19 episodes per 100 patient-years). 1
Avoid using sliding scale insulin as monotherapy. Scheduled insulin regimens with basal, prandial, and correction components are superior to reactive correction-only approaches. 1
Monitoring Requirements
- Daily self-monitoring of blood glucose before meals and snacks, occasionally postprandially, at bedtime, prior to exercise, and when suspecting low blood glucose 1
- Check A1C at least quarterly when therapy has changed or goals are not being met 1
- Reassess and modify therapy every 3-6 months to avoid therapeutic inertia 1