What is the management approach for a patient with hyperglycemia (elevated blood glucose level) over 130 mg/dL using an insulin sliding scale of 1:15 (one unit of regular insulin to 15 mg/dL of glucose)?

Sliding Scale Insulin Alone Should Not Be Used for Glucose Over 130 mg/dL

Sliding scale insulin (SSI) as a sole therapy is strongly discouraged for hospitalized patients and should be replaced with a scheduled basal-bolus insulin regimen, which provides superior glycemic control and reduces complications. 1, 2

Why Sliding Scale Insulin Fails

Sliding scale insulin is a reactive approach that treats hyperglycemia after it occurs, leading to:

• Rapid blood glucose fluctuations that worsen both hyperglycemia and hypoglycemia 2
• Poor glycemic control, with only 38% of patients achieving mean blood glucose <140 mg/dL compared to 68% with basal-bolus regimens 2
• Ineffective outcomes, with 84% of SSI injections failing to bring glucose into target range (90-130 mg/dL) 3
• Persistent hyperglycemia without corresponding adjustments in insulin dosing in 81% of patients 3

The Recommended Approach: Basal-Bolus Insulin

For patients with glucose consistently >130 mg/dL, implement a scheduled basal-bolus regimen rather than relying on SSI alone:

Initial Dosing Strategy

For insulin-naive patients or those on low insulin doses:

• Start with 0.3-0.5 units/kg total daily dose (TDD) 1, 2
• Allocate 50% to basal insulin (given once or twice daily) 1
• Allocate 50% to rapid-acting insulin (divided before three meals) 1
• Use lower doses (0.1-0.25 units/kg) for high-risk patients: elderly (>65 years), renal failure, poor oral intake 1

For patients already on insulin at home:

• If using ≥0.6 units/kg/day, reduce home TDD by 20% during hospitalization to prevent hypoglycemia 1, 2

When SSI May Be Acceptable (Limited Circumstances)

SSI alone can be considered only in highly specific situations 1:

• Patients without diabetes who have mild stress hyperglycemia 2
• Patients with good baseline control (HbA1c <7%) on diet or low-dose oral agents 1
• Patients who are NPO with no nutritional replacement 1

However, even in these cases, if glucose cannot be maintained <180 mg/dL, basal insulin must be added. 1

Evidence for Superiority of Basal-Bolus Regimens

Randomized trials consistently demonstrate 1, 2:

• Better glycemic control with basal-bolus versus SSI alone in type 2 diabetes
• Reduced complications including postoperative wound infections, pneumonia, bacteremia, and acute renal/respiratory failure 1
• More predictable glucose patterns by providing proactive rather than reactive insulin coverage

Critical Pitfall to Avoid

Never use SSI alone in patients with type 1 diabetes - this population requires continuous insulin coverage and SSI monotherapy can lead to diabetic ketoacidosis 1

Hypoglycemia Risk Considerations

While basal-bolus regimens carry 4-6 times higher hypoglycemia risk than SSI (12-30% incidence in controlled settings), this reflects more aggressive glucose control rather than inappropriate therapy 1. The key is proper dosing and monitoring:

• Reassess the regimen if glucose falls <100 mg/dL 1
• Modify the regimen when glucose is <70 mg/dL 1
• Consider a basal-plus approach (basal insulin + correction doses only) for patients with mild hyperglycemia (<200 mg/dL), decreased oral intake, or surgical patients 1

Practical Implementation

For a patient with glucose >130 mg/dL on a 1:15 sliding scale:

1. Calculate TDD: For a 70 kg patient = 0.4 units/kg × 70 kg = 28 units total daily
2. Divide dosing: 14 units basal (e.g., glargine once daily) + 14 units rapid-acting (approximately 5 units before each meal)
3. Add correction doses using the 1:15 ratio for glucose >130 mg/dL as supplemental coverage 2
4. Adjust based on response: If correction doses are frequently needed, increase scheduled insulin accordingly 2