What is the initial dose of regular insulin for a patient with an Hemoglobin A1C (HbA1C) level of 13.5?

Initial Insulin Therapy for Patient with A1C 13.5%

For a patient with an A1C of 13.5%, immediate initiation of basal insulin at 0.1-0.2 units/kg/day is recommended, along with concurrent metformin therapy if renal function is normal.

Initial Assessment and Treatment Approach

• Evaluate for symptoms of hyperglycemia (polyuria, polydipsia, weight loss) and assess for possible ketosis/ketoacidosis or hyperglycemic hyperosmolar state 1
• Check blood glucose levels; if ≥250 mg/dL with symptoms or ≥600 mg/dL regardless of symptoms, follow appropriate emergency protocols 1, 2
• Start basal insulin immediately while simultaneously initiating metformin (if renal function is normal) for marked hyperglycemia (A1C ≥8.5%) with symptoms 1
• Initial insulin dosing should start at 0.1-0.2 units/kg/day and be titrated based on blood glucose response 1

Insulin Regimen Selection

• For patients with A1C ≥8.5% (69 mmol/mol) who are symptomatic with polyuria, polydipsia, nocturia, and/or weight loss, basal insulin should be initiated while metformin is started and titrated 3
• If the patient has ketosis/ketoacidosis, treatment with subcutaneous or intravenous insulin should be initiated to rapidly correct the hyperglycemia and metabolic derangement 3
• If blood glucose remains poorly controlled on basal insulin up to 1.5 units/kg/day, transition to multiple daily injections with basal and premeal bolus insulins 3

Monitoring and Titration

• Monitor blood glucose frequently, with self-monitoring multiple times daily 1
• Assess glycemic status every 3 months with HbA1c testing 3, 1
• Titrate basal insulin dose to achieve fasting blood glucose targets of 80-130 mg/dL 1
• For patients initially treated with insulin and metformin who meet glucose targets, insulin can be tapered over 2–6 weeks by decreasing the insulin dose 10–30% every few days 3

Glycemic Targets

• Target A1C should be <7% for most patients 1
• More stringent targets (<6.5%) may be appropriate for patients with short duration of diabetes or lesser degrees of β-cell dysfunction 1
• Less stringent targets (7.5% or higher) may be appropriate with history of severe hypoglycemia, limited life expectancy, or advanced complications 1

Common Pitfalls to Avoid

• Using sliding scale insulin alone without basal insulin is ineffective and strongly discouraged 2
• Delaying insulin therapy for severe hyperglycemia increases risk of complications 2
• Verify diabetes type, considering possibility of type 1 diabetes, especially in younger, leaner patients 1
• Inadequate monitoring of blood glucose can lead to both persistent hyperglycemia and hypoglycemic events 2

Special Considerations

• For older adults, glycemic targets should be individualized based on health status, with less stringent targets for those with complex health issues or limited life expectancy 3
• For youth with marked hyperglycemia, initial treatment with basal insulin while metformin is initiated is recommended 3
• Recent evidence suggests that GLP-1 receptor agonists may be as effective as insulin for patients with high A1C levels, but insulin remains the standard initial therapy for severely elevated A1C 4