Recommended Insulin Protocol for Initiating Therapy in Diabetes
For patients with type 2 diabetes requiring insulin therapy, basal insulin should be initiated at 10 units per day or 0.1-0.2 units/kg/day, depending on the degree of hyperglycemia. 1, 2
Initial Insulin Selection and Dosing
Basal Insulin Initiation
- Basal insulin alone is the most convenient initial insulin regimen for most patients with type 2 diabetes 2, 1
- Start with 10 units per day or 0.1-0.2 units/kg/day of basal insulin, titrating over days to weeks as needed 2, 3
- Long-acting insulin analogs (glargine, detemir, degludec) are preferred over NPH insulin due to lower risk of hypoglycemia 2, 4
- Detemir has shown significantly lower risk of severe hypoglycemia compared to NPH insulin in real-world studies 4
- Continue metformin when initiating insulin therapy 2, 1
Special Circumstances for Immediate Insulin Initiation
- Consider immediate insulin therapy when 1, 2:
- HbA1c ≥10% (86 mmol/mol)
- Blood glucose ≥300 mg/dL (16.7 mmol/L)
- Symptoms of hyperglycemia are present
- Evidence of ongoing catabolism (weight loss, ketosis)
- Type 1 diabetes is suspected
Titration and Adjustment
Basal Insulin Titration
- Increase dose by 10-15% or 2-4 units once or twice weekly until fasting glucose target is achieved 2
- Empower patients with self-titration algorithms based on self-monitoring to improve glycemic control 2, 1
- Watch for clinical signs of overbasalization 2:
- Basal dose >0.5 units/kg
- High bedtime-to-morning glucose differential
- Hypoglycemia (aware or unaware)
- High glucose variability
When to Add Prandial Insulin
- If basal insulin has been optimally titrated (or dose >0.5 units/kg/day) and HbA1c remains above target, consider adding prandial insulin 2, 5
- Before adding prandial insulin, consider adding a GLP-1 receptor agonist if not already being used 2
- When initiating prandial insulin, start with 4 units, 0.1 units/kg, or 10% of the basal dose before the largest meal or meal with greatest postprandial excursion 5, 2
- When adding significant prandial insulin doses, consider decreasing basal insulin 2
Insulin Regimen Options
Basal-Bolus Regimen
- Preferred approach for patients with type 1 diabetes and some with type 2 diabetes 6
- Consists of basal insulin (once or twice daily) plus rapid-acting insulin before meals 2
- Rapid-acting insulin analogs (lispro, aspart, glulisine) are preferred for mealtime coverage due to quicker onset of action 5, 2
Premixed Insulin Options
- Consider premixed insulin products for patients who may benefit from simpler dosing 2
- Contains fixed proportions of basal and prandial insulin components 2
- Main disadvantage is requiring relatively fixed meal schedule and carbohydrate content 2
Medication Management with Insulin Initiation
Concomitant Medications
- Continue metformin when initiating insulin therapy 1, 2
- Consider discontinuing sulfonylureas, DPP-4 inhibitors, and GLP-1 receptor agonists when using complex insulin regimens beyond basal insulin 1, 2
- Thiazolidinediones or SGLT-2 inhibitors may improve control and reduce total daily insulin dose 2
Common Pitfalls to Avoid
- Delaying insulin therapy in patients not achieving glycemic goals 1
- Using insulin as a threat or describing it as a sign of personal failure 1, 2
- Overbasalization (continuing to increase basal insulin when prandial coverage is needed) 2
- Inadequate patient education on self-monitoring, diet, and hypoglycemia management 1, 2
- Using sliding-scale insulin alone without basal insulin 7
Patient Education
- Provide comprehensive education on self-monitoring of blood glucose, diet, and hypoglycemia recognition/treatment 1, 2
- Explain the progressive nature of type 2 diabetes and the role of insulin therapy 1
- Teach proper injection technique and site rotation to prevent lipohypertrophy 6
- Instruct on self-titration algorithms to improve glycemic control 2, 1