What is the initial dosing approach for insulin in type 1 diabetes?

Initial Insulin Dosing for Type 1 Diabetes

The recommended starting insulin dose for type 1 diabetes is 0.5 units/kg/day for metabolically stable adults, with approximately half as basal insulin and half as prandial insulin. 1

Initial Dosing Approach

• Total daily insulin requirements typically range from 0.4 to 1.0 units/kg/day for patients with type 1 diabetes 1
• For metabolically stable adults, 0.5 units/kg/day is the typical starting dose 1, 2
• Higher doses may be required during puberty, menses, and medical illness 1
• Lower doses (0.2-0.6 units/kg) may be appropriate for young children and those with continued endogenous insulin production (during the "honeymoon period") 1
• Patients presenting with ketoacidosis may require higher initial doses 1

Insulin Distribution

• Generally, 30-50% of the total daily insulin should be administered as basal insulin, with the remainder as prandial insulin 1
• For a typical starting regimen, approximately half is given as basal insulin and half as prandial insulin 1, 2
• This proportion may vary based on individual factors including carbohydrate consumption, age, pregnancy status, and puberty stage 1

Treatment Regimens

• Most people with type 1 diabetes should be treated with either:
  • Multiple daily injections (MDI) of prandial and basal insulin 1
  • Continuous subcutaneous insulin infusion (CSII) via insulin pump 1
• Rapid-acting insulin analogs are recommended for prandial insulin to reduce hypoglycemia risk 1
• For MDI regimens, a typical approach combines:
  • Long-acting basal insulin (once or twice daily) to regulate overnight and fasting glucose 1
  • Rapid-acting prandial insulin before meals to manage postprandial glucose excursions 1

Dose Adjustment and Titration

• Education on matching prandial insulin to carbohydrate intake, premeal glucose levels, and anticipated physical activity is essential 1
• Prandial insulin should ideally be administered before meals, with timing based on:
  • The insulin formulation (regular, rapid-acting, or inhaled)
  • Premeal blood glucose level
  • Carbohydrate content of the meal 1
• Basal insulin should be titrated to regulate overnight and fasting glucose 1
• Consider adjusting prandial insulin doses for protein and fat intake, in addition to carbohydrates 1

Special Considerations

• Automated insulin delivery (AID) systems are preferred when feasible and should be considered for patients capable of using the device safely 1
• Continuous glucose monitoring (CGM) can improve glycemic control regardless of insulin delivery method 3
• All patients with type 1 diabetes should be prescribed glucagon due to the risk of hypoglycemia 1
• Patients and their close contacts should be educated on glucagon administration 1

Common Pitfalls to Avoid

• Using NPH insulin as basal insulin in type 1 diabetes can lead to suboptimal control due to its peak, short duration, and high variability 4
• Failing to adjust insulin doses based on self-monitoring of blood glucose can result in poor glycemic control 2
• Not recognizing that insulin requirements may change with weight changes, illness, or changes in physical activity 2
• Overbasalization (using higher than necessary basal insulin doses) can mask insufficient mealtime insulin coverage 2

By following these evidence-based guidelines for initial insulin dosing in type 1 diabetes, clinicians can establish an effective foundation for glycemic management while minimizing the risk of hypoglycemia and optimizing patient outcomes.