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

Sliding Scale Insulin Should Be Abandoned in Hospitalized Patients

Sliding scale insulin (SSI) as monotherapy is strongly discouraged and should not be used as the primary treatment approach for hospitalized patients with diabetes. 1 This reactive approach treats hyperglycemia after it occurs rather than preventing it, leading to dangerous glucose fluctuations and poor outcomes. 2, 3

Why Sliding Scale Insulin Fails

Evidence of Ineffectiveness

• SSI achieves good glycemic control in only 2-10% of hospitalized patients, with the majority (51-68%) remaining poorly controlled throughout their hospital stay. 4
• Only 12% of SSI injections successfully reduced elevated glucose to target range (90-130 mg/dL), while 84% of injections were subtherapeutic with glucose remaining elevated. 4
• SSI regimens were never adjusted in 81% of patients despite persistently elevated glucose levels, demonstrating the inherent passivity of this approach. 4

Safety Concerns

• Approximately 30% of SSI administration points had missing documentation regarding execution, timing, glucose levels, or insulin dose—creating dangerous gaps in care. 4
• SSI is associated with hypoglycemic episodes without providing adequate glycemic control. 4

The Recommended Alternative: Basal-Bolus Insulin Regimen

For hospitalized patients requiring insulin, use a scheduled basal-bolus regimen rather than SSI alone. 1, 2

Initial Dosing Algorithm

For insulin-naive or low-dose patients:

• Calculate total daily dose (TDD) as 0.3-0.5 units/kg/day 1, 2
• Divide as 50% basal insulin (given once daily) and 50% prandial insulin (divided equally before three meals) 1, 2

For high-risk populations (elderly >65 years, renal failure, poor oral intake):

• Use lower doses of 0.1-0.25 units/kg/day to prevent hypoglycemia 1, 2

For patients on high-dose home insulin (≥0.6 units/kg/day):

• Reduce total daily dose by 20% upon hospitalization to prevent hypoglycemia 1, 2, 3

Evidence Supporting Basal-Bolus Over SSI

Randomized trials demonstrate clear superiority:

• 68% of patients on basal-bolus achieved mean glucose <140 mg/dL versus only 38% on SSI alone 2
• Basal-bolus regimens reduce postoperative complications including wound infections and acute renal failure 2
• Better overall glycemic control with reduced hospital complications 1, 2

Target Glucose Ranges

• Non-critically ill hospitalized patients: 140-180 mg/dL 1, 2
• Fasting glucose target: 80-130 mg/dL 1

When SSI Might Be Acceptable (Very Limited Circumstances)

SSI as monotherapy may only be appropriate for: 2, 3

• Patients without pre-existing diabetes who develop mild stress hyperglycemia 2, 3
• Patients with well-controlled type 2 diabetes (HbA1c <7%) on diet alone or minimal oral therapy at home who have mild hyperglycemia during hospitalization 3
• Patients who are NPO with no nutritional replacement and only mild hyperglycemia 2
• Patients who are new to steroids or tapering steroids 2

Practical Implementation: Basal-Plus Approach for Poor Oral Intake

For patients with poor oral intake or NPO status:

• Use basal insulin at 0.1-0.25 units/kg/day given once daily 2, 3
• Add correction doses of rapid-acting insulin before meals or every 6 hours if NPO for glucose >180 mg/dL 2, 3
• This "basal-plus" approach is superior to SSI alone 2, 3

Simplified Correction Dosing (as adjunct only, not monotherapy)

• 2 units of rapid-acting insulin for premeal glucose >250 mg/dL 1, 2
• 4 units of rapid-acting insulin for premeal glucose >350 mg/dL 1, 2

Critical Pitfalls to Avoid

Never use SSI as monotherapy for patients with established diabetes requiring insulin therapy. 1, 2 This approach:

• Treats hyperglycemia reactively rather than preventing it 2
• Leads to dangerous glucose fluctuations 2, 3
• Results in poor glycemic control in the majority of patients 4
• Is associated with inadequate monitoring and documentation 4

Avoid premixed insulin (70/30) in hospitalized patients due to unacceptably high hypoglycemia rates compared to basal-bolus regimens. 2

If correction doses are frequently required, increase the scheduled basal and prandial insulin doses accordingly rather than continuing to rely on reactive corrections. 2

Monitoring Requirements

• Point-of-care glucose testing before each meal and at bedtime for patients eating regular meals 1
• Every 4-6 hours for patients with poor oral intake 1
• Target conventional glucose range of 140-180 mg/dL for most hospitalized patients 2

Hypoglycemia Risk Considerations

Basal-bolus regimens provide superior glycemic control but carry increased hypoglycemia risk:

• 4-6 times higher risk of hypoglycemia compared to SSI alone (RR 5.75 for glucose ≤70 mg/dL) 3
• However, this risk is manageable with appropriate dosing adjustments for high-risk populations 1, 2
• The improved glycemic control and reduced complications outweigh this risk when properly implemented 2