Correctional Insulin in Basal-Bolus Regimens with Pre-meal and Bedtime Monitoring
Correctional insulin is an essential component of a basal-bolus regimen that provides supplemental insulin doses to "correct" high blood glucose readings detected during pre-meal and bedtime monitoring, working alongside basal and prandial insulin to achieve optimal glycemic control.
Understanding the Basal-Bolus-Correction Framework
A comprehensive insulin regimen for glycemic control consists of three components:
- Basal insulin: Long-acting insulin administered once or twice daily to control blood glucose between meals and overnight
- Prandial (bolus) insulin: Rapid-acting insulin given before meals to cover carbohydrate intake
- Correctional insulin: Supplemental rapid-acting insulin given to correct high blood glucose readings
When to Check Blood Glucose and Apply Correctional Insulin
For patients on a basal-bolus regimen with pre-meal and bedtime monitoring:
- Check blood glucose before each meal and at bedtime 1
- Apply correctional insulin at these same times when blood glucose exceeds target levels
- Correctional insulin is typically administered using the same rapid-acting insulin used for meal coverage
Implementing Correctional Insulin in Practice
Step 1: Establish Target Blood Glucose Range
- Typical target range: 90-150 mg/dL before meals 2
Step 2: Create a Correctional Scale Based on Insulin Sensitivity
Correctional scales are typically categorized as:
- Low-dose scale: For insulin-sensitive patients (elderly, renal impairment)
- Moderate-dose scale: For most patients
- High-dose scale: For insulin-resistant patients
Example of correctional insulin scale 2:
| Blood Glucose (mg/dL) | Low-Dose Scale | Moderate-Dose Scale | High-Dose Scale |
|---|---|---|---|
| 140-180 | 1 unit | 2 units | 3 units |
| 181-220 | 2 units | 4 units | 6 units |
Step 3: Calculate Total Insulin Dose at Each Monitoring Point
When blood glucose is checked before a meal:
- Total insulin dose = Prandial insulin (for carbohydrate coverage) + Correctional insulin (if needed)
When blood glucose is checked at bedtime:
- Only correctional insulin is given (no prandial component)
- Use caution with bedtime correction to avoid overnight hypoglycemia
Example Calculation
For a patient with:
- Blood glucose of 250 mg/dL before a meal
- Meal containing 60g carbohydrates
- Insulin-to-carbohydrate ratio of 1:10
- Correction factor of 1:25 with target of 125 mg/dL
The calculation would be 1:
- Prandial insulin: 60g ÷ 10 = 6 units
- Correctional insulin: (250 - 125) ÷ 25 = 5 units
- Total insulin dose: 6 + 5 = 11 units
Adjusting the Regimen Based on Monitoring Patterns
Rather than adjusting insulin doses based on single readings, look for patterns:
- For persistent high fasting glucose: Increase basal insulin by 2 units if 50% of fasting values are above target 2
- For persistent pre-meal hyperglycemia: Adjust previous meal's prandial insulin or correction factor
- For hypoglycemia: Decrease the relevant insulin component (basal or prandial) by 2 units if blood glucose falls below 80 mg/dL more than twice weekly 2
Important Considerations and Pitfalls
Avoid These Common Mistakes:
Using sliding scale insulin alone: This reactive approach is strongly discouraged as it treats hyperglycemia after it occurs rather than preventing it 1, 2
Failing to adjust doses based on patterns: Correctional insulin should inform adjustments to the overall regimen, not just repeatedly correct the same problem
Ignoring nutritional status: For patients with poor oral intake, reduce total insulin dose to 0.1-0.15 units/kg/day, primarily as basal insulin 1
Overlooking hypoglycemia risk: Be cautious with bedtime correctional insulin, especially in elderly patients or those with renal impairment 1
Special Situations:
- NPO (nothing by mouth) status: Use basal insulin plus correctional insulin only (no prandial component) 2
- Variable meal timing: Administer prandial insulin immediately after meals rather than before, adjusting dose based on actual intake 1
Evidence-Based Recommendations
Research clearly demonstrates that basal-bolus-correction regimens are superior to sliding scale insulin alone:
- Randomized trials show better glycemic control and fewer complications with basal-bolus approaches compared to sliding scale insulin 1, 3
- The basal-plus-correction approach (basal insulin with correctional doses) is effective for patients with mild hyperglycemia or decreased oral intake 1, 3
By properly implementing correctional insulin within a basal-bolus framework and using pre-meal and bedtime glucose monitoring to guide adjustments, you can achieve optimal glycemic control while minimizing the risk of hypoglycemia.