Is a blood glucose level of hyperglycemia at bedtime a concern for a patient already on a sliding scale of insulin (Regular Insulin) therapy?

Bedtime Blood Glucose of 12.3 mmol/L (221 mg/dL) on Sliding Scale Insulin

Yes, a bedtime glucose of 12.3 mmol/L (221 mg/dL) is concerning and indicates your current sliding scale insulin regimen is inadequate—you need to transition immediately to a scheduled basal-bolus insulin regimen rather than relying on reactive sliding scale coverage alone. 1, 2

Why This Glucose Level Matters

Your bedtime glucose of 221 mg/dL significantly exceeds the recommended target of <180 mg/dL for hospitalized patients 1. This level of persistent hyperglycemia is associated with:

• Increased infection risk through impaired immune function, including decreased white blood cell mobilization and phagocytic activity 3
• Higher in-hospital mortality and complications, even in patients without pre-existing diabetes 4, 5
• Poor overall glycemic control that sliding scale insulin alone cannot adequately address 1, 2

The Critical Problem: Sliding Scale Insulin Alone is Inadequate

The American Diabetes Association explicitly states that sliding scale insulin (SSI) as the sole method of treatment is strongly discouraged in hospitalized patients. 1, 2 Here's why your current approach is failing:

• SSI treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations 2
• SSI provides no basal insulin coverage between meals or overnight, allowing glucose to rise unchecked 2
• Randomized trials demonstrate that basal-bolus regimens provide superior glycemic control and reduce hospital complications compared to SSI alone 2

What You Need Instead: Basal-Bolus Insulin Regimen

For a patient already requiring insulin with glucose levels in the 220s mg/dL, you need scheduled basal insulin (like Lantus/glargine) plus correction insulin (like Lispro), not SSI alone. 2

Recommended Starting Regimen:

Basal Insulin Component:

• Start with 10 units of long-acting basal insulin (Lantus/glargine) once daily at the same time each day 2, 6
• Alternatively, use 0.1-0.2 units/kg body weight as your starting dose 2, 6
• This provides essential 24-hour background insulin coverage 2

Correction Insulin Component:

• Continue short-acting insulin (Lispro) before meals only as correction doses 2
• Use a simplified scale: 2 units for glucose >250 mg/dL, 4 units for glucose >350 mg/dL 2
• Never use rapid-acting insulin at bedtime due to nocturnal hypoglycemia risk 2

Titration Protocol:

Increase basal insulin aggressively based on fasting glucose patterns 2, 6:

• If fasting glucose ≥180 mg/dL: increase by 4 units every 3 days 2
• If fasting glucose 140-179 mg/dL: increase by 2 units every 3 days 2
• Target fasting glucose: 80-130 mg/dL (4.4-7.2 mmol/L) 2

Monitoring Requirements

• Check fasting glucose daily during titration to guide basal insulin adjustments 2
• Monitor for hypoglycemia, especially overnight between midnight and 6:00 AM when risk peaks 1
• If glucose falls <100 mg/dL (5.6 mmol/L), reassess the regimen 1
• If glucose <70 mg/dL (3.9 mmol/L), reduce insulin dose by 10-20% immediately 1, 2

Critical Threshold to Watch

When your basal insulin dose exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, you'll need to add mealtime (prandial) insulin rather than continuing to escalate basal insulin alone. 2 Signs you've reached this threshold include:

• Bedtime-to-morning glucose differential ≥50 mg/dL 2
• Hypoglycemia episodes 2
• High glucose variability 2

Common Pitfalls to Avoid

• Don't continue SSI as your only treatment—this unnecessarily prolongs hyperglycemia exposure and increases complication risk 1, 2
• Don't withhold basal insulin when glucose is elevated—this is a common error that worsens hyperglycemia 2
• Don't delay insulin adjustments—basal insulin can be adjusted every 3 days even while receiving correction insulin 2
• Don't ignore persistent hyperglycemia—glucose levels consistently >180 mg/dL require immediate regimen changes 1

Special Considerations

If you have poor oral intake or are NPO (nothing by mouth), a basal-plus-correction regimen is still preferred over SSI alone, with correction doses given every 4-6 hours 1, 2. For patients on high-dose home insulin (≥0.6 units/kg/day), reduce the total daily dose by 20% during hospitalization to prevent hypoglycemia 7.