What are examples of insulin regimens for patients with type 1 and type 2 diabetes?

Insulin Regimens for Type 1 and Type 2 Diabetes

For optimal morbidity, mortality, and quality of life outcomes, multiple daily injections with long-acting insulin analogs plus rapid-acting insulin analogs represent the most effective insulin regimen for type 1 diabetes, while type 2 diabetes patients should start with basal insulin and progress to more complex regimens as needed. 1

Type 1 Diabetes Insulin Regimens

Preferred Regimens (Highest to Lowest)

1. Hybrid Closed-Loop Technology

   • Provides the highest flexibility and lowest risk of hypoglycemia
   • Uses continuous glucose monitoring with automated insulin delivery
   • Significantly reduces hypoglycemia risk and improves time in target range 1

2. Insulin Pump with Threshold/Predictive Low-Glucose Suspend

   • Automatically suspends insulin delivery when glucose levels drop or are predicted to drop
   • Offers excellent flexibility and reduced hypoglycemia risk 1

3. Multiple Daily Injections (MDI) with Long-Acting Analog + Rapid-Acting Analog

   • Basal: Long-acting insulin analog (glargine, detemir, degludec) once or twice daily
   • Bolus: Rapid-acting insulin analog (lispro, aspart, glulisine) before meals
   • Generally 50% of total daily dose as basal insulin 1, 2
   • Provides good flexibility and lower hypoglycemia risk compared to older regimens

Alternative Regimens (Less Preferred)

• MDI with NPH + Rapid-Acting Analog: More variable glucose control
• MDI with NPH + Regular Insulin: Less physiologic coverage
• Twice-daily premixed insulin: Least flexible option 1, 3

Type 2 Diabetes Insulin Regimens

Progressive Approach to Insulin Therapy

1. Initial Insulin Therapy (When oral agents fail to achieve target HbA1c)

   • Basal insulin only: Start with long-acting insulin once daily
     • Initial dose: 10 units or 0.1-0.2 units/kg/day
     • Titrate by 2-4 units every 3 days until fasting glucose target reached (80-130 mg/dL) 1
     • Continue metformin; consider discontinuing sulfonylureas and DPP-4 inhibitors 1

2. Intensification (If HbA1c remains above target after basal optimization)

   • Option A: Add GLP-1 receptor agonist to basal insulin

     • Less weight gain and hypoglycemia than adding prandial insulin 1

   • Option B: Progress to basal-bolus regimen

     • Add one prandial insulin dose before largest meal
     • Start with 4 units or 10% of basal dose 1, 4
     • Further intensify to multiple prandial doses if needed

   • Option C: Switch to twice-daily premixed insulin

     • Simpler but less flexible than basal-bolus 1

Insulin Selection and Administration

Types of Insulin

• Rapid-acting analogs (lispro, aspart, glulisine): Onset 5-15 min, peak 1-2 hrs, duration 4-6 hrs
• Short-acting (regular): Onset 30-60 min, peak 2-3 hrs, duration 6-8 hrs
• Intermediate-acting (NPH): Onset 2-4 hrs, peak 4-10 hrs, duration 12-18 hrs
• Long-acting analogs (glargine, detemir, degludec): Onset 1-2 hrs, minimal peak, duration 20-24+ hrs 1, 5

Proper Administration

• Use short needles (4-mm pen needles) to avoid intramuscular injection 1, 6
• Inject into subcutaneous tissue of abdomen, thigh, buttock, or upper arm 1
• Rotate injection sites within the same area to reduce lipohypertrophy 1
• Do not inject into areas of lipohypertrophy as it distorts insulin absorption 6

Special Considerations

Resource-Limited Settings

• Human insulin (NPH and regular) is recommended as first-line due to cost considerations 1
• Consider long-acting insulin analogs only for patients with frequent severe hypoglycemia on human insulin 1

Dosing Adjustments

• Basal insulin: Adjust based on fasting glucose patterns

  • If FBG ≥180 mg/dL: Increase by 6-8 units
  • If FBG 140-179 mg/dL: Increase by 4 units
  • If FBG 120-139 mg/dL: Increase by 2 units
  • If hypoglycemia occurs: Decrease by 10-20% 4

• Prandial insulin: Adjust based on postprandial glucose

  • If PPG >200 mg/dL: Increase by 2-4 units
  • If PPG 150-200 mg/dL: Increase by 1-2 units
  • If hypoglycemia occurs: Decrease by 10-20% 4

Common Pitfalls to Avoid

1. Intramuscular injection: Can lead to unpredictable absorption and hypoglycemia 1
2. Overbasalization: Using excessive basal insulin instead of adding prandial coverage 4
3. Abrupt discontinuation of oral agents: Can cause rebound hyperglycemia when starting insulin 6
4. Inappropriate injection technique: Can lead to variable insulin absorption 1
5. Ignoring patient's lifestyle: Failing to match insulin regimen to meal and activity patterns 1

By following these evidence-based approaches to insulin therapy, clinicians can optimize glycemic control while minimizing the risks of hypoglycemia and other adverse outcomes, ultimately improving morbidity, mortality, and quality of life for patients with diabetes.