What are the steps for initiating insulin therapy in patients with diabetes?

Step-by-Step Guide to Initiating Insulin Therapy

The most effective approach to initiating insulin therapy involves starting with basal insulin at 10 units daily or 0.1-0.2 units/kg/day for type 2 diabetes, with subsequent dose titration based on blood glucose monitoring, while providing comprehensive patient education on injection technique, hypoglycemia management, and self-monitoring. 1

Initial Assessment and Decision-Making

• Determine the appropriate timing for insulin initiation based on glycemic control: consider starting insulin when HbA1c ≥9% or blood glucose levels ≥300-350 mg/dL, and especially when HbA1c is 10-12% with symptomatic hyperglycemia 1
• Identify the type of diabetes (type 1 or type 2) as this determines the initial insulin regimen 2, 1
• For patients with type 1 diabetes, multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII) should be initiated at diagnosis 2
• For patients with type 2 diabetes, basal insulin alone is typically the most convenient initial regimen 2, 1

Selecting the Initial Insulin Regimen

For Type 1 Diabetes:

• Start with multiple daily injections consisting of basal insulin plus prandial insulin 2
• The recommended starting dosage is approximately one-third of the total daily insulin requirements as basal insulin, with the remainder as prandial insulin 3
• Consider insulin analogs to reduce hypoglycemia risk 2

For Type 2 Diabetes:

• Begin with basal insulin at 10 units per day or 0.1-0.2 units/kg/day, depending on the degree of hyperglycemia 1, 3
• Continue metformin and possibly one additional non-insulin agent when initiating insulin 2, 1
• For severe hyperglycemia with symptoms, consider basal insulin plus mealtime insulin as the initial regimen 1

Insulin Administration Instructions

• Administer basal insulin subcutaneously once daily at any time of day, but at the same time every day 3
• Inject into the abdominal area, thigh, or deltoid, and rotate injection sites within the same region to reduce lipodystrophy risk 3
• Visually inspect insulin for particulate matter and discoloration prior to administration 3
• Do not dilute or mix insulin glargine with any other insulin or solution 3
• Use the shortest needles available (4-mm pen or 6-mm syringe needles) for less painful injections 4

Dose Titration Protocol

• Equip patients with a self-titration algorithm based on fasting blood glucose monitoring 2, 1
• Increase the basal insulin dose by 10-15% or 2-4 units once or twice weekly until the fasting blood glucose target is met 2
• During dose adjustments, increase the frequency of blood glucose monitoring 3
• Use fasting plasma glucose values to titrate basal insulin, and both fasting and postprandial glucose values to titrate mealtime insulin when applicable 4

Patient Education Components

• Provide comprehensive education on blood glucose monitoring, nutrition, and hypoglycemia recognition and treatment 2, 5
• Teach patients with type 1 diabetes how to match prandial insulin dose to carbohydrate intake, premeal blood glucose, and anticipated activity 2
• Address common concerns about insulin therapy including fear of injections, hypoglycemia, and weight gain 6
• Explain the progressive nature of type 2 diabetes and the role of insulin therapy to avoid using insulin as a threat or describing it as a sign of personal failure 2

When to Intensify Insulin Therapy

• If basal insulin has been titrated to an acceptable fasting blood glucose level but HbA1c remains above target, consider advancing to combination injectable therapy 2, 1
• Options for intensification include:
  • Adding a GLP-1 receptor agonist 2, 1
  • Adding mealtime insulin with a starting dose of 4 units, 0.1 units/kg, or 10% of the basal dose per meal 1
  • Using premixed insulin products for patients who may benefit from simpler dosing 2

Special Considerations and Common Pitfalls

• Watch for signs of overbasalization: basal dose >0.5 units/kg, high bedtime-morning glucose differential, hypoglycemia, or high variability 2
• When switching from other insulin therapies to insulin glargine, adjust dosages to lower hypoglycemia risk:
  • From once-daily NPH: use same dosage 3
  • From twice-daily NPH: use 80% of the total NPH dosage 3
• Consider discontinuing sulfonylureas, DPP-4 inhibitors, and GLP-1 receptor agonists when using more complex insulin regimens beyond basal insulin 2, 1
• Avoid delaying insulin therapy in patients not achieving glycemic goals 1, 7

By following this systematic approach to insulin initiation, healthcare providers can help patients achieve optimal glycemic control while minimizing the risk of adverse events such as hypoglycemia.