What is the recommended approach for correction dosing of short-acting insulin (Regular insulin)?

Correction Dosing for Short-Acting Insulin (Regular Insulin)

For correction dosing of short-acting insulin, use a simplified sliding scale approach: give 2 units for premeal glucose >250 mg/dL (>13.9 mmol/L) and 4 units for premeal glucose >350 mg/dL (>19.4 mmol/L), but discontinue this sliding scale when not needed daily. 1

Key Principles for Correction Dosing

Simplified Sliding Scale Approach

The American Diabetes Association recommends a straightforward correction strategy while adjusting prandial insulin regimens 1:

• For premeal glucose >250 mg/dL (>13.9 mmol/L): Administer 2 units of short- or rapid-acting insulin 1
• For premeal glucose >350 mg/dL (>19.4 mmol/L): Administer 4 units of short- or rapid-acting insulin 1
• Critical caveat: Stop the sliding scale when it is not needed daily, as this indicates better baseline control has been achieved 1

Important Timing Restrictions

Do not use rapid- or short-acting insulin at bedtime for routine correction dosing 1. This is a common pitfall that increases nocturnal hypoglycemia risk.

Evidence on Bedtime Correction Dosing

A 2015 randomized controlled trial specifically examined bedtime supplemental insulin for correction of hyperglycemia in hospitalized patients 2. The study found that:

• Routine bedtime insulin supplementation for blood glucose >7.8 mmol/L (140 mg/dL) did not improve fasting glucose control 2
• There was no difference in mean fasting blood glucose between groups receiving bedtime supplements versus no supplements (8.8 vs 8.6 mmol/L, P = 0.76) 2
• Hypoglycemia rates were similar between groups 2

This high-quality evidence demonstrates that routine bedtime correction dosing is not indicated and should be avoided 2.

Alternative Formula-Based Approaches

Correction Factor Calculation

For more individualized correction dosing, the correction factor (CF) can be calculated using total daily dose (TDD) 3, 4:

• CF = 1500 / TDD (where TDD is the total daily insulin dose in units) 3
• Alternative formula: CF = 1960 / TDD 4

This correction factor represents how many mg/dL one unit of insulin will lower blood glucose 3, 4.

Practical Application

Once the correction factor is determined, the correction dose equals: (Current glucose - Target glucose) / Correction Factor 3, 4

Integration with Prandial Insulin Regimens

When initiating prandial insulin therapy, the American Diabetes Association recommends 1:

• Start with 4 units per day or 10% of basal insulin dose for the first prandial dose 1
• Increase by 1-2 units or 10-15% of the dose for titration 1
• For hypoglycemia without clear cause, lower the corresponding dose by 10-20% 1

Critical Safety Considerations

Hypoglycemia Management

When hypoglycemia occurs 1:

• Determine the cause first
• If no clear reason is identified, reduce the insulin dose by 10-20% 1
• Consider prescribing glucagon for emergent hypoglycemia 1

Target Glucose Goals

For older adults or those requiring simplified regimens 1:

• Premeal goal: 90-150 mg/dL (5.0-8.3 mmol/L) 1
• Adjust goals based on overall health status and goals of care 1

Common Pitfalls to Avoid

1. Avoid bedtime correction dosing with short- or rapid-acting insulin as routine practice 1, 2
2. Do not continue sliding scale indefinitely - discontinue when not needed daily 1
3. Do not use correction-only insulin without basal coverage in hospitalized patients, as this leads to worse outcomes 1
4. Avoid mixing short-acting insulin with lente insulins unless the patient is already well-controlled on such a mixture 1