What are the initial insulin therapy guidelines for diabetic patients?

Initial Insulin Therapy Guidelines for Diabetic Patients

For patients with type 2 diabetes, initial insulin therapy should start with basal insulin at 0.1-0.2 units/kg/day or 10 units once daily when oral agents have failed to achieve glycemic targets. 1

Type 1 Diabetes Insulin Initiation

For patients with type 1 diabetes, insulin therapy is the mainstay of treatment and should be initiated immediately at diagnosis:

• Starting dose: 0.4-1.0 units/kg/day of total insulin 1
• Typical starting dose for metabolically stable patients: 0.5 units/kg/day 1
• Regimen: Multiple daily injections (MDI) with:
  • Rapid-acting insulin analogs before meals
  • One or more daily injections of basal insulin 1

Type 2 Diabetes Insulin Initiation

The decision to start insulin in type 2 diabetes depends on several factors:

When to Initiate Insulin

• When HbA1c ≥ 7.5% despite optimized oral agents 2
• Essential when HbA1c ≥ 10% 2
• When blood glucose ≥ 300-350 mg/dL and/or HbA1c 10-12%, especially with symptoms 1
• During acute illness, surgery, pregnancy, or when oral medications are contraindicated 2

Initial Insulin Regimen Options

1. Basal Insulin (First-Line):

   • Starting dose: 0.1-0.2 units/kg/day or 10 units once daily 1, 3
   • Options include glargine, detemir, degludec, or NPH 1
   • Typically used with metformin and possibly one additional non-insulin agent 1
   • Administer at the same time each day 3

2. For Severe Hyperglycemia (HbA1c ≥ 10% or glucose ≥ 300 mg/dL with symptoms):

   • Basal insulin plus mealtime insulin is the preferred initial regimen 1
   • Consider starting with basal-bolus regimen if patient has catabolic features 1

Insulin Titration

Basal Insulin Titration

• Adjust dose every 3 days based on fasting blood glucose 4
• Titration algorithm:
  • FBG ≥ 180 mg/dL: Increase by 6-8 units
  • FBG 140-179 mg/dL: Increase by 4 units
  • FBG 120-139 mg/dL: Increase by 2 units
  • FBG 100-119 mg/dL: Maintain or increase by 0-2 units
  • FBG < 100 mg/dL: Decrease by 2-4 units
  • Any hypoglycemia (< 70 mg/dL): Decrease by 10-20% 4

When to Intensify Beyond Basal Insulin

• If HbA1c remains above target despite optimized basal insulin with appropriate fasting glucose levels 1
• Options for intensification:
  1. Add a GLP-1 receptor agonist 1
  2. Add prandial insulin (1-3 injections of rapid-acting insulin before meals) 1
  3. Switch to twice-daily premixed insulin 1
  4. Move to basal-bolus regimen (multiple daily injections) 1

Special Considerations

Youth with Type 2 Diabetes

• For metabolically stable youth (A1C < 8.5% and asymptomatic): Start with metformin 1
• For youth with marked hyperglycemia (blood glucose ≥ 250 mg/dL, A1C ≥ 8.5%) with symptoms: Start with basal insulin while initiating metformin 1
• For youth with ketosis/ketoacidosis: Start with insulin to correct metabolic derangement, then add metformin once acidosis resolves 1

Practical Administration Tips

• Administer subcutaneously into abdomen, thigh, or deltoid 3
• Rotate injection sites to reduce risk of lipodystrophy 3
• Do not administer intravenously or via insulin pump unless specifically prescribed 3
• Do not dilute or mix with other insulins or solutions 3

Common Pitfalls to Avoid

1. Delayed insulin initiation: Don't hesitate to start insulin when indicated, as delayed therapy can worsen outcomes 1

2. Inadequate dose titration: Timely dose adjustment is crucial for achieving glycemic targets 1

3. Failure to monitor: Increase frequency of blood glucose monitoring when changing insulin regimens 3

4. Inappropriate discontinuation of oral agents: Don't abruptly stop oral medications when starting insulin due to risk of rebound hyperglycemia 2

5. Ignoring hypoglycemia risk: Be vigilant about hypoglycemia, especially when using intensive insulin regimens or in patients with renal impairment 4

6. Neglecting patient education: Ensure patients understand insulin administration, glucose monitoring, and hypoglycemia management 4