From the Guidelines
For an A1C greater than 13, aggressive treatment is necessary to reduce blood glucose levels and prevent complications, and the most recent guidelines from 2020 suggest starting with a combination therapy approach, typically including both metformin and insulin therapy 1.
Treatment Approach
The treatment approach should include:
- Metformin, starting at 500mg twice daily, gradually increasing to 1000mg twice daily as tolerated
- Basal insulin, such as insulin glargine or detemir, initiated at 0.2-0.3 units/kg/day
- Mealtime rapid-acting insulin, such as insulin lispro, aspart, or glulisine, dosed at 0.1-0.15 units/kg per meal
Monitoring and Adjustments
Frequent blood glucose monitoring is essential, checking levels before meals and at bedtime, with insulin doses adjusted every 2-3 days based on patterns 1.
Lifestyle Modifications
Lifestyle modifications are crucial, including:
- A consistent carbohydrate diet
- Regular physical activity
- Adequate hydration
Evaluation for Complications
Patients should be evaluated for diabetic ketoacidosis, especially if type 1 diabetes is suspected 1.
Rationale
This aggressive approach is necessary because an A1C above 13 indicates severe hyperglycemia (average blood glucose >325 mg/dL), which significantly increases the risk of acute complications like hyperosmolar hyperglycemic state and long-term complications affecting the eyes, kidneys, nerves, and cardiovascular system 1.
From the FDA Drug Label
The Insulin Glargine group had a smaller mean reduction from baseline in HbA1c compared to the NPH insulin group, which may be explained by the lower daily basal insulin doses in the Insulin Glargine group (Table 11).
The treatment for HbA1c greater than 13 is not directly addressed in the provided drug labels. However, the labels do provide information on the effectiveness of Insulin Glargine in reducing HbA1c levels in patients with type 1 and type 2 diabetes.
- In Study E, Insulin Glargine administered once daily at bedtime was as effective as NPH insulin administered once daily at bedtime in reducing HbA1c and fasting glucose.
- In Study F, Insulin Glargine had similar effectiveness as either once- or twice-daily NPH insulin in reducing HbA1c and fasting glucose.
- In Study G, the Insulin Glargine group had a smaller mean reduction from baseline in HbA1c compared to the NPH insulin group.
Based on the available data, it can be inferred that Insulin Glargine may be effective in reducing HbA1c levels, but the optimal treatment strategy for HbA1c greater than 13 is not explicitly stated in the drug labels 2 2.
From the Research
Treatment for A1C Greater Than 13
- The American Association of Clinical Endocrinologists and the American Diabetes Association recommend considering insulin administration for people with type 2 diabetes with HbA1c levels exceeding 9.0% and 10%, respectively 3.
- However, studies have shown that metformin-based dual-agent oral treatment approaches can be effective in reducing HbA1c levels, even in patients with baseline HbA1c >11% 3.
- GLP-1 receptor agonists, such as exenatide and liraglutide, have been shown to be superior to insulin glargine in reducing HbA1c levels in patients with type 2 diabetes 3.
- The combination of a GLP-1RA with a thiazolidinedione, such as pioglitazone, may be an effective treatment option for patients with type 2 diabetes and high HbA1c levels 3.
- SGLT-2 inhibitors, such as canagliflozin and dapagliflozin, have been shown to be effective in reducing HbA1c levels and may be associated with a lower risk of hyperkalemia compared to DPP-4 inhibitors 4.
Alternative Treatment Options
- Metformin, alpha-glucosidase inhibitors, pioglitazone, GLP-1 agonists, DPP-IV inhibitors, and SGLT-2 inhibitors may be used as alternative agents in addition to insulin therapy for patients with type 1 diabetes 5.
- These medications can help reduce insulin resistance and prevent or deter weight gain, and may be associated with a lower risk of hypoglycemia 5.
Considerations for Treatment
- The choice of treatment should be individualized based on the patient's specific needs and circumstances 3, 6.
- Patients with high HbA1c levels (>13) may require more intensive treatment, such as insulin therapy or combination therapy with oral medications 3.
- The risk of hyperkalemia should be considered when selecting treatment options, particularly for patients with kidney disease or those taking certain medications 4.