What is the recommended approach for managing blood glucose levels using a sliding scale insulin regimen?

Sliding Scale Insulin Should Be Avoided as Monotherapy in Hospitalized Patients

The sole use of sliding scale insulin (SSI) in the inpatient hospital setting is strongly discouraged and should be replaced with scheduled basal insulin regimens, as SSI alone is associated with poor glycemic control, increased hyperglycemic episodes, and no reduction in complications. 1

Why Sliding Scale Insulin Fails

Sliding scale insulin operates reactively rather than proactively, treating hyperglycemia after it has already occurred rather than preventing it. 1 This approach leads to:

• Poor glycemic control: SSI alone achieved target glucose control in only 38% of patients compared to 68% with basal-bolus insulin 2
• Increased hyperglycemic episodes: Meta-analysis shows significantly higher mean blood glucose levels (14.8 mg/dL higher) and more hyperglycemic events with SSI 3, 4
• No clinical benefit: When used alone, SSI provides no advantage over no pharmacologic treatment and is associated with a 3-fold higher risk of hyperglycemic episodes 5
• Persistent poor control: 51-68% of patients on SSI remain poorly controlled throughout hospitalization, with regimens rarely adjusted despite ongoing hyperglycemia 6

Recommended Approach: Basal-Bolus or Basal-Plus Regimens

For Non-Critically Ill Patients with Good Oral Intake

Use a basal-bolus insulin regimen consisting of: 1, 2

• Total daily dose: 0.3-0.5 units/kg for insulin-naive patients or those on low doses 1
• Distribution: 50% as basal insulin (once or twice daily) + 50% as rapid-acting prandial insulin (divided before three meals) 1, 2
• Plus correction doses: Add rapid-acting insulin for pre-meal hyperglycemia 2

Lower doses (0.1-0.25 units/kg) should be used for high-risk patients: 1

• Older adults (>65 years)
• Renal failure
• Poor oral intake

For patients on high home insulin doses (≥0.6 units/kg/day): Reduce total daily dose by 20% during hospitalization to prevent hypoglycemia 1

For Non-Critically Ill Patients with Poor Oral Intake or NPO

Use a basal-plus approach consisting of: 1, 2

• Basal insulin: 0.1-0.25 units/kg/day as a single daily dose 1
• Plus correction doses: Rapid-acting insulin for elevated glucose before meals or every 6 hours if NPO 1

This approach is preferred for: 1

• Patients with mild hyperglycemia (blood glucose <200 mg/dL)
• Those with decreased oral intake
• Patients undergoing surgery
• Fasting patients

For Critically Ill Patients

Use continuous intravenous insulin infusion with: 1, 7

• Target range: 140-180 mg/dL for most patients 1
• Initiation threshold: Start insulin therapy at blood glucose >180 mg/dL 1

Limited Acceptable Uses of Sliding Scale Insulin Alone

SSI alone may be appropriate ONLY in these specific circumstances: 1, 2

• Patients without diabetes who have mild stress hyperglycemia 1
• Well-controlled diabetes (HbA1c <7%) on minimal home therapy with only mild hyperglycemia during hospitalization 2
• NPO patients with no nutritional replacement and only mild hyperglycemia 2
• Steroid-related hyperglycemia in patients new to steroids or tapering steroids 2

Critical exception: SSI alone should NEVER be used in patients with type 1 diabetes 1

Evidence Supporting These Recommendations

Randomized controlled trials consistently demonstrate: 1, 2

• Superior glycemic control: Basal-bolus regimens achieve better glucose control than SSI alone in type 2 diabetes 1
• Reduced complications: Basal-bolus approach reduces postoperative wound infections, pneumonia, bacteremia, and acute renal/respiratory failure 1
• Better outcomes despite hypoglycemia risk: Although basal-bolus insulin carries 4-6 times higher risk of hypoglycemia than SSI, the overall clinical outcomes favor scheduled insulin regimens 1

Critical Pitfalls to Avoid

• Never use SSI as monotherapy in type 1 diabetes: These patients require basal insulin to prevent diabetic ketoacidosis 1
• Don't continue ineffective SSI regimens: If glucose remains elevated on SSI, transition to scheduled basal insulin rather than continuing the same failing approach 6, 5
• Avoid premixed insulin (70/30): This formulation has unacceptably high hypoglycemia rates in hospitalized patients 1
• Don't forget to reduce insulin doses: Patients with poor oral intake or transitioning from home require dose reductions to prevent hypoglycemia 1

Hypoglycemia Risk Management

While basal-bolus regimens carry higher hypoglycemia risk (12-30% incidence of mild hypoglycemia in controlled settings), this must be balanced against: 1

• The proven reduction in complications and better glycemic control 1
• The fact that severe hypoglycemia remains low in controlled settings 1
• The ability to mitigate risk through appropriate dose selection and monitoring 1

Every hospital should implement a hypoglycemia management protocol with clear treatment plans for each patient 1