What are the guidelines for type 1 insulin titration?

Type 1 Diabetes Insulin Titration Guidelines

Initial Insulin Dosing

Start with a total daily dose (TDD) of 0.5 units/kg/day for metabolically stable adults with type 1 diabetes, dividing this approximately 50% as basal insulin and 50% as prandial insulin. 1, 2

• The acceptable range for TDD is 0.4-1.0 units/kg/day, but 0.5 units/kg/day serves as the standard starting point 3, 1, 2
• For patients presenting with diabetic ketoacidosis, use higher weight-based dosing than the standard 0.5 units/kg/day 1, 2
• Young children and those in the "honeymoon period" with residual endogenous insulin production require lower doses of 0.2-0.6 units/kg/day 1, 2

Basal-Prandial Distribution

Administer 30-50% of TDD as basal insulin (typically given as once-daily long-acting insulin like glargine), with the remaining 50-70% divided as prandial insulin before meals. 1, 2

• Most patients with type 1 diabetes should use multiple daily injections (MDI) of prandial and basal insulin or continuous subcutaneous insulin infusion (CSII) 3, 2
• Rapid-acting insulin analogs (aspart, lispro, glulisine) are preferred over regular human insulin for prandial coverage to reduce hypoglycemia risk 3, 2, 4

Basal Insulin Titration

Titrate basal insulin based on fasting blood glucose values, adjusting the dose to achieve fasting glucose of 80-130 mg/dL (4.4-7.2 mmol/L). 5, 6

• For insulin glargine specifically, the titration goal is premeal blood glucose of 4.4-6.7 mmol/l (approximately 80-120 mg/dL) 6
• If fasting glucose remains elevated, increase basal insulin by 2-4 units every 3 days until target is reached 5
• If hypoglycemia occurs, immediately reduce the basal dose by 10-20% 5
• Critical threshold: When basal insulin exceeds 0.5 units/kg/day, reassess the regimen rather than continuing to escalate, as this may indicate inadequate prandial coverage rather than insufficient basal insulin 5

Prandial Insulin Titration

Educate patients to match prandial insulin doses to carbohydrate intake, premeal blood glucose levels, and anticipated physical activity. 3, 2

• Use the insulin-to-carbohydrate ratio (ICR) formula: ICR = 300 / TDD 7
• Use the correction factor (CF) formula: CF = 1500 / TDD 7
• The relationship between dosing factors can be represented as: 100 / total basal dose = ICR = CF / 4.5 7
• Adjust prandial insulin by 1-2 units or 10-15% every 3 days based on postprandial glucose readings 5
• Consider adjusting for protein and fat intake in addition to carbohydrates 2

Special Populations Requiring Higher Doses

Increase insulin doses during puberty, pregnancy, medical illness (infections, inflammation), and menses, as requirements may approach or exceed 1.0 units/kg/day. 3, 1, 2

• Adolescents during puberty often require doses approaching the upper limit of 1.0 units/kg/day or higher 1, 2
• Pregnant women with type 1 diabetes require progressive dose increases throughout pregnancy 1, 2
• Acute illness increases insulin resistance and necessitates temporary dose escalation 1, 2

Continuous Glucose Monitoring Integration

Use continuous glucose monitoring (CGM) to guide insulin titration, targeting time-in-range (TIR) of 70-180 mg/dL greater than 70% while minimizing time below 70 mg/dL to less than 4%. 4, 8

• CGM improves glycemic control irrespective of whether patients use MDI or insulin pump therapy 4
• Perform insulin adjustments based on CGM patterns every 3-7 days during active titration 7
• Look for patterns of hyperglycemia or hypoglycemia at specific times of day to guide basal versus prandial adjustments 7

Critical Pitfalls to Avoid

Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this leads to "overbasalization" with increased hypoglycemia risk and suboptimal control. 5

• Overbasalization manifests as bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability 5
• When basal insulin exceeds 0.5 units/kg/day and A1C remains elevated despite controlled fasting glucose, add or optimize prandial insulin rather than further increasing basal insulin 5
• Ensure patients inject rapid-acting insulin immediately before meals (0-15 minutes), not after eating, to effectively manage postprandial glucose 1
• Never mix insulin glargine with other insulins due to its low pH formulation 5

Insulin Delivery Modality Selection

Consider continuous subcutaneous insulin infusion (insulin pump) for patients not meeting glycemic targets on MDI, those with frequent or severe hypoglycemia, or those with pronounced dawn phenomenon. 4

• Pump therapy provides modest advantages for lowering A1C (approximately -0.30%) and reducing severe hypoglycemia rates compared to MDI 3
• Automated insulin delivery (AID) systems are preferred when feasible and should be considered for patients capable of using the device safely 2
• Patients successfully using CSII should have continued access after age 65 3

Hypoglycemia Management

All patients with type 1 diabetes must be prescribed glucagon, and both patients and close contacts should receive education on its administration. 2

• If severe hypoglycemia occurs, reduce insulin doses by 10-20% immediately and investigate the cause 5
• Target fewer than 4% of time below 70 mg/dL and minimize time below 54 mg/dL 8