Is my current insulin regimen of 28 International Units (IU) of Xsulin (human insulin 30/70) in the morning and 18 IU at night at risk of causing over-basalisation?

Is Your Current Insulin 30/70 Regimen at Risk of Over-Basalisation?

Your regimen of 28 IU morning and 18 IU evening of premixed insulin 30/70 (total 46 IU/day) is NOT technically over-basalisation, but premixed insulins carry inherent risks that make them suboptimal for long-term glycemic control.

Understanding Your Current Regimen

Your insulin 30/70 is a premixed formulation containing:

• 30% rapid/short-acting insulin (for meal coverage)
• 70% intermediate-acting insulin (NPH, for basal coverage)

This means your actual basal insulin component is approximately 32 IU/day (70% of 46 IU), not the full 46 IU 1.

Why This Isn't Classic Over-Basalisation

Over-basalisation specifically refers to excessive pure basal insulin (like glargine or detemir) exceeding 0.5 units/kg/day while neglecting prandial coverage 1. Your premixed insulin already contains both components, so the traditional definition doesn't directly apply 2.

However, premixed insulins have significant limitations:

Critical Problems with Premixed Insulin Regimens

• Randomized trials demonstrate that premixed insulins cause significantly increased hypoglycemia rates compared to basal-bolus regimens 2
• Premixed insulins provide inferior glycemic control with more hospital complications than properly dosed basal-bolus therapy 2
• The fixed ratio (30/70) cannot be adjusted independently—you cannot increase meal coverage without also increasing basal insulin, or vice versa 2
• Major diabetes guidelines explicitly recommend against premixed insulin use in hospital settings due to unacceptably high iatrogenic hypoglycemia rates 2

Signs You May Need Regimen Optimization

Watch for these warning patterns that indicate your current regimen may be inadequate 1:

• Bedtime-to-morning glucose differential ≥50 mg/dL (≥2.8 mmol/L)—suggests the basal component is too high
• Hypoglycemia between meals or overnight—indicates excessive insulin at those times
• High postprandial glucose excursions despite controlled fasting glucose—suggests inadequate prandial coverage
• A1C remaining above goal despite reasonable fasting glucose (80-130 mg/dL)—indicates the fixed ratio isn't meeting your needs
• Wide glucose fluctuations throughout the day—characteristic of premixed insulin's inflexible dosing

The Superior Alternative: Basal-Bolus Therapy

If you're experiencing any of the above patterns, transitioning to separate basal and prandial insulins provides better control with less hypoglycemia 2, 3:

Conversion Strategy

To convert your current regimen 2:

1. Calculate your total daily dose: 46 IU
2. Split 50:50 between basal and prandial components
3. Give 23 IU of basal insulin (glargine or detemir) once daily
4. Divide remaining 23 IU as rapid-acting insulin across three meals (approximately 8 IU per meal, adjusted based on meal size)

Why This Approach Works Better

• Basal-bolus therapy provides better glycemic control with reduced hospital complications compared to premixed insulin 2
• You can independently adjust basal vs. prandial doses based on glucose patterns 3
• Rapid-acting insulin analogues provide more physiologic meal coverage with lower hypoglycemia risk 3
• Scheduled basal-bolus regimens are superior to premixed insulin approaches 2

Monitoring Your Current Regimen

If continuing premixed insulin for now, monitor for these critical thresholds 1:

• Check fasting glucose daily—target 80-130 mg/dL
• Check 2-hour postprandial glucose after largest meal—target <180 mg/dL
• Monitor for hypoglycemia, especially overnight and between meals
• Measure bedtime and morning glucose to calculate the differential
• Check A1C every 3 months

When to Definitely Transition

Consider transitioning from premixed to basal-bolus therapy when 2:

• Your total daily dose exceeds 0.5 units/kg/day without achieving A1C goals
• Fasting glucose is controlled but A1C remains above target after 3-6 months
• You experience recurrent hypoglycemia
• You need more flexible dosing for varying meal sizes or timing

Common Pitfalls to Avoid

• Never continue premixed insulin in situations requiring precise glucose control (hospitalization, surgery, acute illness) 2
• Don't assume higher doses of premixed insulin will solve persistent hyperglycemia—the fixed ratio may be the problem 1
• Avoid treating hypoglycemia by reducing both components when only one needs adjustment 3
• Don't delay transition to basal-bolus therapy if glucose patterns indicate the fixed ratio isn't working 2