What is the recommended approach to initiate insulin therapy?

Initiating Insulin Therapy in Diabetes

The recommended approach to initiate insulin therapy is to start with basal insulin at 10 units per day or 0.1-0.2 units/kg/day, depending on the degree of hyperglycemia, while maintaining metformin and possibly one additional non-insulin agent. 1, 2

Initial Assessment for Insulin Therapy

• Consider insulin therapy when A1C ≥9% or blood glucose levels ≥300-350 mg/dL, and especially when A1C is 10-12% with symptomatic hyperglycemia 2, 3
• For severe hyperglycemia with symptoms, consider basal insulin plus mealtime insulin as the initial regimen 2
• Identify the type of diabetes as this determines the initial insulin regimen approach 3

Basal Insulin Initiation

• Start with basal insulin at 10 units per day or 0.1-0.2 units/kg/day, depending on the degree of hyperglycemia 1
• Preferred basal insulin options include long-acting analogs such as glargine, detemir, or degludec 2
• Continue metformin when initiating insulin therapy 1, 2
• Long-acting basal analogs (glargine or detemir) can be used instead of NPH insulin to reduce hypoglycemia risk 1, 4

Titration Protocol

• Set a fasting plasma glucose (FPG) target 1
• Use an evidence-based titration algorithm: increase dose by 2 units every 3 days until FPG target is reached without hypoglycemia 1, 2
• If hypoglycemia occurs, determine the cause; if no clear reason, lower the dose by 10-20% 1
• Equip patients with a self-titration algorithm based on self-monitoring of blood glucose to improve glycemic control 2, 5

When to Intensify Beyond Basal Insulin

• Assess adequacy of basal insulin dose; watch for signs of overbasalization (basal dose >0.5 units/kg/day, high bedtime-morning glucose differential, hypoglycemia) 1
• If A1C remains above target despite optimized basal insulin, consider advancing to combination injectable therapy 1
• Options for intensification include:
  • Adding a GLP-1 receptor agonist (preferred option due to less weight gain and hypoglycemia) 1
  • Adding prandial insulin, starting with one dose at the largest meal 1, 6

Adding Prandial Insulin

• Start with one dose with the largest meal or meal with greatest postprandial glucose excursion 1
• Initial prandial insulin dose: 4 units per day or 10% of basal dose 1
• When adding prandial insulin, consider reducing basal insulin by 4 units or 10% of the basal dose 1
• Titrate prandial dose by 1-2 units or 10-15% twice weekly 1

Further Intensification if Needed

• If A1C remains above target, add stepwise additional injections of prandial insulin (progressing from one to three meals) 1
• For full basal-bolus regimen, add 4 units of rapid-acting insulin to each meal or 10% of the basal dose 1, 6

Medication Management with Insulin

• Continue metformin when initiating insulin therapy 1
• Consider discontinuing sulfonylureas, DPP-4 inhibitors, and GLP-1 receptor agonists when using more complex insulin regimens beyond basal insulin 1
• Thiazolidinediones or SGLT2 inhibitors may be continued to improve glucose control and reduce total insulin requirements 1

Patient Education

• Provide comprehensive education on self-monitoring of blood glucose, diet, and exercise 1, 2
• Teach recognition, prevention, and treatment of hypoglycemia 1, 2
• Educate patients on the progressive nature of type 2 diabetes and the role of insulin therapy 2

Common Pitfalls to Avoid

• Delaying insulin therapy in patients not achieving glycemic goals 2
• Using insulin as a threat or describing it as a sign of personal failure 2
• Inadequate dose titration leading to persistent hyperglycemia 2, 5
• Overbasalization without addressing postprandial hyperglycemia 1