What is the standard insulin therapy regimen for type 1 diabetes management?

Standard Insulin Therapy for Type 1 Diabetes Management

Most people with type 1 diabetes should be treated with multiple daily injections (MDI) of prandial and basal insulin or continuous subcutaneous insulin infusion (CSII) using rapid-acting insulin analogs to reduce hypoglycemia risk. 1, 2

First-Line Insulin Regimens

Multiple Daily Injections (MDI)

• Consists of:
  • Basal insulin: Long-acting insulin analog (provides background insulin)
  • Prandial insulin: Rapid-acting insulin analog before meals (covers meal-related glucose excursions)
• Typical starting dose: 0.5 units/kg/day of total insulin for metabolically stable patients 1
  • Range: 0.4-1.0 units/kg/day
  • Higher doses may be required during puberty or following ketoacidosis
• Dosing distribution: Approximately 50% basal and 50% prandial insulin

Continuous Subcutaneous Insulin Infusion (CSII/Insulin Pump)

• Delivers continuous basal insulin with patient-activated boluses for meals
• Slight advantage over MDI in HbA1c reduction (-0.30% difference) 1
• Particularly beneficial for patients with:
  • Nocturnal hypoglycemia
  • Hypoglycemia unawareness
  • Wide glucose fluctuations

Insulin Types and Administration

Preferred Insulins

• Rapid-acting analogs (aspart, lispro, glulisine) for prandial coverage 1, 2, 3
  • Administer immediately before meals
  • Reduces hypoglycemia risk compared to regular human insulin
• Long-acting analogs (glargine, detemir, degludec) for basal coverage
  • Provides more stable background insulin levels

Insulin Dosing Considerations

• Prandial insulin doses should be matched to:
  • Carbohydrate intake (carbohydrate counting)
  • Pre-meal blood glucose levels
  • Anticipated physical activity 1, 2
• Advanced patients who have mastered carbohydrate counting should also learn fat and protein gram estimation 1, 2

Glucose Monitoring and Hypoglycemia Management

• Continuous glucose monitoring (CGM) is strongly recommended for improved glycemic outcomes 2
• For hypoglycemia treatment:
  • Use 15-20g of glucose (preferably glucose tablets)
  • Recheck blood glucose after 15-20 minutes
  • Repeat treatment if hypoglycemia persists 2
• Prescribe glucagon for all individuals taking insulin 2

Advanced Insulin Delivery Systems

• Sensor-augmented insulin pump therapy with threshold suspend feature reduces nocturnal hypoglycemia 1
• Hybrid closed-loop insulin pump systems can automatically adjust basal insulin rates based on glucose values 1, 2
• These systems should be encouraged in selected patients with active patient/family participation 1

Clinical Outcomes and Benefits

• Intensive insulin therapy (MDI or CSII) improves glucose control and results in better long-term outcomes 1
• Benefits include:
  • Reduced microvascular complications (retinopathy, nephropathy)
  • Reduced neuropathic complications
  • Reduced cardiovascular events
  • Modest reduction in all-cause mortality 1

Common Pitfalls and Caveats

• Avoid sliding-scale insulin as the sole treatment strategy 2
• Ensure patients carry carbohydrate sources to prevent hypoglycemia during physical activity 2
• Despite benefits of intensive therapy, there remains risk of hypoglycemia
• Insulin analogs are associated with less hypoglycemia than human insulins 1
• Use the shortest needles available (4-mm pen, 6-mm syringe) to avoid intramuscular injections 4
• Avoid injections into lipohypertrophy areas as they distort insulin absorption 4

Adjunctive Therapies

• GLP-1 receptor agonists and DPP-4 inhibitors are being studied in type 1 diabetes but are not currently FDA-approved for this indication 1, 2
• SGLT2 inhibitors provide insulin-independent glucose lowering but also lack FDA approval for type 1 diabetes 1

Insulin therapy remains the cornerstone of type 1 diabetes management, with the goal of achieving near-normoglycemia while minimizing hypoglycemia risk and improving quality of life.