Insulin Therapy for Type 1 Diabetes

Introduction to Insulin Therapy

• 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/insulin pump) therapy to optimize glycemic control and reduce mortality risk 1

Basal Insulin Therapy

• Basal insulin should account for 50% of total daily insulin requirement, with long-acting insulin analogs (glargine, degludec) preferred over NPH due to lower hypoglycemia risk 2, 3
• Basal insulin is typically administered once or twice daily 2

Prandial Insulin Therapy

• Prandial insulin should account for 50% of total daily insulin requirement, with rapid-acting insulin analogs (aspart, lispro) preferred over regular human insulin 1, 3
• Prandial insulin should be administered before meals (0-15 minutes prior) 1

Initial Insulin Dosing

• Initial total daily insulin dose should be 0.4-1.0 units/kg/day 2, 3
• Typical starting dose for metabolically stable patients is 0.5 units/kg/day 3
• Higher doses may be required during puberty, pregnancy, or medical illness 2

Insulin Dose Adjustment

• Prandial insulin doses should be matched to carbohydrate intake, pre-meal blood glucose levels, and anticipated physical activity 1, 3
• Patients who have mastered carbohydrate counting can further improve control with education on fat and protein gram estimation 3

Continuous Subcutaneous Insulin Infusion (CSII)

• CSII should be considered for patients with frequent hypoglycemia on MDI, those with pronounced dawn phenomenon, or patients with nocturnal hypoglycemia (sensor-augmented pump with threshold suspend feature) 3

Reducing Hypoglycemia Risk

• Rapid-acting insulin analogs can reduce hypoglycemia risk 1
• Sensor-augmented insulin pump therapy with threshold suspend feature can be considered for patients with nocturnal hypoglycemia 3, 4
• Newer longer-acting basal analogs (U-300 glargine or degludec) may confer lower hypoglycemia risk compared to U-100 glargine 2

Insulin Injection Technique

• Insulin should be injected into subcutaneous tissue, not intramuscularly 2
• Recommended injection sites include the abdomen, thigh, buttock, and upper arm 2

Monitoring and Evaluation

• Continuous glucose monitoring (CGM) is strongly recommended for all patients with type 1 diabetes 5
• Insulin treatment plan should be evaluated every 3-6 months 5

Avoiding Common Pitfalls

• Sole use of sliding scale insulin is strongly discouraged 6
• Abrupt discontinuation of insulin therapy can lead to diabetic ketoacidosis
• Intramuscular injections can cause unpredictable absorption and hypoglycemia 2
• Inadequate education on carbohydrate counting and dose adjustment can lead to poor control
• Failure to adjust insulin for physical activity can lead to hypoglycemia 5