What is the recommended sliding scale for regular (insulin) in a patient with impaired glucose regulation?

Sliding Scale Insulin Should Not Be Used as Monotherapy

The use of sliding scale insulin (SSI) alone for managing hyperglycemia in hospitalized patients is strongly discouraged and should be replaced with a scheduled basal-bolus insulin regimen. 1

Why Sliding Scale Insulin Fails

Sliding scale insulin is fundamentally flawed because it treats hyperglycemia reactively after it occurs rather than preventing it. 1 This approach leads to:

• Poor glycemic control: Only 6% of patients achieve good control with SSI, with 51-68% remaining poorly controlled 2
• Increased hyperglycemic events: Meta-analysis shows significantly higher mean blood glucose (27.33 mg/dL higher) and more hyperglycemic episodes compared to scheduled insulin regimens 3
• Dangerous glucose variability: SSI creates wide fluctuations that increase complication risk 2, 3
• Treatment failure: 19% treatment failure rate with SSI versus 0-2% with basal-bolus regimens 1

The Correct Approach: Basal-Bolus Insulin Regimen

For Noncritically Ill Patients with Good Oral Intake

Use a scheduled basal-bolus regimen with three components: 1

1. Basal insulin (glargine, detemir, or degludec) once daily
2. Prandial insulin (lispro, aspart, or glulisine) before each meal
3. Correction insulin only as needed for glucose >180 mg/dL

Initial Dosing Algorithm

For insulin-naive or low-dose patients: 1, 4

• Start with 0.3-0.5 units/kg/day total daily dose
• Give 50% as basal insulin once daily
• Give 50% as prandial insulin divided equally before three meals

For high-risk patients (elderly >65 years, renal failure, poor oral intake): 1, 4

• Use lower doses of 0.1-0.25 units/kg/day

For Patients with Poor Oral Intake or NPO

Use basal-plus correction insulin: 1, 4

• Continue basal insulin at reduced dose
• Add correction insulin only when glucose >180 mg/dL
• Avoid prandial insulin if not eating

Glycemic Targets

For noncritically ill hospitalized patients: 1

• Premeal glucose: <140 mg/dL (7.8 mmol/L)
• Random glucose: <180 mg/dL (10.0 mmol/L)

For critically ill patients: 1

• Target range: 140-180 mg/dL (7.8-10.0 mmol/L)
• More stringent targets of 110-140 mg/dL may be appropriate for select patients (e.g., cardiac surgery) if achievable without hypoglycemia 1

If Correction Insulin Is Needed

When using correction doses as an adjunct to scheduled insulin: 5, 6

• For glucose 250-350 mg/dL: Add 2 units rapid-acting insulin
• For glucose >350 mg/dL: Add 4 units rapid-acting insulin

Never give rapid-acting insulin at bedtime due to nocturnal hypoglycemia risk. 1, 5

Evidence Supporting This Approach

Randomized controlled trials demonstrate that basal-bolus regimens compared to SSI result in: 1

• Better glycemic control: Mean glucose 161 mg/dL vs 175 mg/dL
• Fewer complications: 9% vs 24% complication rate in surgical patients
• Reduced treatment failure: 0-2% vs 19%

A quality improvement study converting from SSI to basal-bolus showed: 7

• 2,434 fewer hypoglycemic events
• 40,589 fewer hyperglycemic events
• 3.18 days shorter length of stay
• 47.4% fewer point-of-care glucose tests

Critical Pitfalls to Avoid

• Never use SSI as monotherapy – it is ineffective and increases complications 1, 2, 3
• Never withhold basal insulin when blood glucose is elevated – this worsens hyperglycemia 6
• Never give rapid-acting insulin at bedtime – this causes nocturnal hypoglycemia 1, 5
• Never delay transition from SSI to scheduled insulin – prolonged hyperglycemia increases complication risk 6

Monitoring Requirements

• Point-of-care glucose testing before each meal for patients eating 1
• Every 4-6 hours for patients with poor oral intake or NPO 4, 6
• Reassess regimen when glucose falls below 100 mg/dL 1, 4
• Modify regimen immediately when glucose <70 mg/dL unless easily explained 1