When should sliding‑scale insulin be initiated and discontinued in an inpatient with hyperglycemia, and what dosing regimen should be used?

When to Initiate and Discontinue Sliding Scale Insulin in Hospitalized Patients with Hyperglycemia

Sliding scale insulin (SSI) alone should be strongly avoided as the sole regimen for hospitalized patients with established diabetes, and basal-bolus insulin regimens are the preferred standard of care for achieving glycemic control and reducing hospital complications. 1, 2

When SSI Should NOT Be Used

The use of SSI as monotherapy is strongly discouraged and condemned in clinical guidelines for the following patients: 1, 2

• Patients with Type 1 diabetes – SSI alone should never be used in this population, as these patients require basal insulin at all times 1, 2
• Patients with Type 2 diabetes on insulin at home – These patients have established insulin requirements and need scheduled basal insulin, not reactive correction only 1, 2
• Patients with moderate to severe hyperglycemia (blood glucose >200 mg/dL) – SSI alone results in poor glycemic control and is associated with increased hospital complications compared to basal-bolus regimens 1, 3, 4

Evidence demonstrates that SSI alone is associated with a 3-fold higher risk of hyperglycemic episodes compared to no pharmacologic treatment, and provides no therapeutic benefit when used as monotherapy. 4

Limited Appropriate Uses of SSI

SSI may be acceptable ONLY in these specific, narrow scenarios: 1, 2

• Patients without diabetes who have mild stress hyperglycemia – These patients may respond adequately to correction insulin alone 1, 2
• Diet-controlled Type 2 diabetes patients with mild hyperglycemia (blood glucose <200 mg/dL) – May start with SSI alone, but basal insulin should be added if glucose levels consistently exceed 180 mg/dL 1, 3, 2

Recommended Insulin Regimens Instead of SSI

For Patients with Good Oral Intake

A basal-bolus-correction regimen is the preferred treatment: 1, 3

• Starting dose: 0.3 units/kg/day total daily dose (TDD) for insulin-naive patients 1, 3
• Basal insulin: 50% of TDD given once daily (glargine, detemir, or degludec preferred over NPH) 1, 3
• Prandial insulin: 50% of TDD divided before three meals using rapid-acting analogs (lispro, aspart, or glulisine) 1, 3
• Correction insulin: Rapid-acting insulin for hyperglycemia as needed 1, 3

This basal-bolus approach reduces postoperative complications including wound infection, pneumonia, bacteremia, and acute renal and respiratory failure compared to SSI alone. 1

For Patients with Poor or No Oral Intake (NPO)

A basal-plus regimen is preferred to minimize hypoglycemia risk: 1, 3

• Starting dose: 0.1-0.25 units/kg/day given mainly as basal insulin 1, 3
• Correction insulin: Rapid-acting insulin before meals or every 6 hours if NPO, for glucose >180 mg/dL 1, 3
• No prandial insulin until oral intake resumes 1, 3

Dose Adjustments for High-Risk Patients

Reduce starting doses to 0.15 units/kg/day or lower for: 1, 3

• Elderly patients (>65 years) 1
• Patients with renal failure 1, 3
• Frail patients with poor oral intake 1, 3

Stratified Approach by Hyperglycemia Severity

The starting regimen should be tailored based on admission blood glucose levels: 3

• Mild hyperglycemia (<200 mg/dL): Start low-dose basal insulin (0.1 units/kg/day) plus correction doses 3
• Moderate hyperglycemia (201-300 mg/dL): Start basal insulin at 0.2-0.3 units/kg/day plus correction doses 3
• Severe hyperglycemia (>300 mg/dL): Initiate full basal-bolus regimen at 0.3 units/kg/day TDD 3

When to Discontinue SSI

SSI should be discontinued and replaced with a basal-bolus regimen as soon as possible, typically within 24-48 hours of admission. 1, 2

If SSI is being used temporarily during insulin dose adjustments, it should be stopped once the patient is stabilized on an appropriate scheduled insulin regimen. 1, 2

For older adults on complex insulin regimens, a simplified correction scale may be used temporarily (e.g., 2 units for glucose >250 mg/dL, 4 units for glucose >350 mg/dL) while adjusting prandial insulin, but should be stopped when not needed daily. 1

Glycemic Targets

Target blood glucose ranges for non-critically ill hospitalized patients: 1, 3

• Premeal glucose: <140 mg/dL 1, 3
• Random glucose: <180 mg/dL 1, 3
• More stringent targets (110-140 mg/dL) may be appropriate for stable patients with previous tight control, but only if achievable without significant hypoglycemia 1, 3

Critical Pitfalls to Avoid

Common errors that lead to poor outcomes: 1, 2

• Using SSI as the sole regimen – This is the most common and dangerous error, resulting in poor glycemic control and increased complications 1, 4
• Withholding basal insulin when blood glucose is elevated – This leads to worsening hyperglycemia 5
• Using premixed insulin formulations (70/30,75/25) – These cause a 3-fold higher rate of hypoglycemia compared to basal-bolus regimens and are not recommended in the hospital 1
• Failing to transition from SSI to scheduled insulin – Prolonged use of SSI alone is associated with poor outcomes 1, 2
• Using NPH insulin in patients with poor oral intake – NPH has a peak action at 8-12 hours, increasing hypoglycemia risk 1

Hypoglycemia Prevention

The risk of hypoglycemia with basal-bolus regimens is 4-6 times higher than with SSI, but this is acceptable given the superior glycemic control and reduced complications. 1

To minimize hypoglycemia risk: 1

• Use lower starting doses (0.1-0.15 units/kg/day) in high-risk patients 1, 3
• Implement a standardized hypoglycemia management protocol 1
• Monitor glucose before meals and at bedtime 1
• Document and track all hypoglycemic episodes 1