Can a correction factor be used to adjust the insulin dose for a patient with diabetes who is taking Mixtard (Novomix, intermediate-acting and short-acting insulin)?

Can Correction Factor Be Used with Mixtard?

Yes, correction factor (supplemental insulin) can and should be used with Mixtard, but scheduled basal-bolus regimens are strongly preferred over sliding-scale-only approaches for optimal glycemic control. 1, 2

Understanding Correction Factor Insulin

Correction factor insulin is designed to address acute hyperglycemic excursions and should be used as part of a comprehensive insulin regimen, not as monotherapy. 1, 2

• The correction factor (insulin sensitivity factor) defines how much one unit of insulin will lower blood glucose, typically calculated as 1500 ÷ Total Daily Dose (TDD) of insulin 3
• For example, if your TDD is 50 units, your correction factor would be 1500 ÷ 50 = 30 mg/dL per unit of insulin 3

Critical Distinction: Scheduled vs. Sliding-Scale Insulin

Sliding-scale insulin alone (correction insulin without scheduled basal/prandial coverage) produces inferior outcomes and should be discouraged. 1

• Basal insulin with preprandial correction doses in hospitalized patients with type 2 diabetes produced better glycemic control and fewer treatment failures than sliding-scale insulin alone 1
• Scheduled basal-bolus regimens are superior to sliding scale monotherapy 3
• Correction insulin is a reactive therapy that does not maintain euglycemia when used alone 2

Practical Application with Mixtard

When using Mixtard (premixed insulin containing both intermediate-acting NPH and short-acting insulin), correction doses can be added to address breakthrough hyperglycemia between scheduled doses. 1

• Use rapid-acting or short-acting insulin for correction doses, administered separately from Mixtard 1
• Calculate correction dose: (Current glucose - Target glucose) ÷ Insulin Sensitivity Factor 3
• Avoid "stacking" correction doses—ensure previous correction insulin has completed its action before administering another dose 3

Titration Algorithm for Mixtard with Correction Factor

The primary focus should be optimizing the scheduled Mixtard doses based on glucose patterns, using correction insulin as supplemental coverage only. 1

• Adjust Mixtard components based on individualized needs and glucose patterns 1
• If hypoglycemia occurs without clear reason, lower the corresponding Mixtard dose by 10-20% 1
• Titrate correction factor doses separately: if corrections consistently fail to bring glucose into target range, adjust the insulin sensitivity factor, not the basal dose 3

Important Considerations for Mixtard Therapy

Premixed insulins like Mixtard have significant limitations compared to basal-bolus regimens, particularly regarding flexibility and hypoglycemia risk. 1, 3

• Premixed insulin should not be used in hospital settings due to unacceptably high rates of iatrogenic hypoglycemia 3
• Consider transitioning to basal-bolus therapy (separate basal and prandial insulin) for better glycemic control with reduced complications 3
• When converting from premixed to basal-bolus, use approximately 50% of total daily dose as basal insulin and 50% as prandial insulin 3

Monitoring Requirements

Daily self-monitoring of blood glucose at multiple time points is essential when using correction factor insulin. 3, 4

• Monitor fasting, pre-meal, and 2-hour postprandial glucose readings 1, 3
• Reassess insulin adequacy at every clinical visit, looking for patterns requiring dose adjustment 1, 3
• Recalculate insulin sensitivity factor periodically (every few weeks to months), especially with changes in weight, illness, or physical activity 3

Common Pitfalls to Avoid

Do not rely solely on correction insulin without addressing inadequate scheduled insulin coverage. 1, 2

• Continuing to use sliding-scale-only approaches when scheduled insulin is needed leads to poor glycemic control 1
• Failure to recognize that correction factor should be adjusted (not basal insulin) when corrections consistently fail to achieve target glucose 3
• Not teaching patients proper insulin injection technique, site rotation, and hypoglycemia recognition when initiating correction insulin 3