What is the appropriate use of sliding scale insulin (SSI) in hospitalized patients with hyperglycemia?

Sliding Scale Insulin in Hospitalized Patients

The sole use of sliding scale insulin (SSI) in hospitalized patients is strongly discouraged and should not be used as monotherapy for patients with established diabetes. 1

When SSI Should NOT Be Used

SSI alone is inappropriate for:

• Patients with Type 1 diabetes - SSI alone should never be used in this population 1
• Patients with Type 2 diabetes on insulin at home - These patients require scheduled basal insulin, not reactive correction only 1
• Patients with established insulin requirements - SSI is associated with clinically significant hyperglycemia and poor outcomes 1

The evidence is clear that SSI monotherapy results in inferior glycemic control compared to basal-bolus regimens, with one study showing a reduction in postoperative complications (wound infection, pneumonia, bacteremia, acute renal and respiratory failure) when using basal-bolus versus SSI alone. 1

Limited Appropriate Uses of SSI

SSI alone may be acceptable only in these specific scenarios:

• Patients without diabetes who have mild stress hyperglycemia - These patients may respond adequately to correction insulin alone 1
• Diet-controlled Type 2 diabetes patients - Those managing without medications at home typically have adequate beta-cell function and may start with SSI alone, adding basal insulin only if glucose consistently exceeds 180 mg/dL 2

This distinction is critical: patients with good metabolic control on diet alone at home represent a fundamentally different population than those requiring pharmacologic therapy. 2

Preferred Insulin Regimens

For Non-Critically Ill Patients with Good Oral Intake:

Use basal-bolus-correction regimen: 1

• Basal insulin: 50% of total daily dose given once or twice daily (long-acting analogs like glargine or detemir preferred) 1
• Prandial insulin: 50% of total daily dose divided before meals (rapid-acting analogs: aspart, lispro, glulisine) 1
• Correction insulin: Rapid-acting insulin for hyperglycemia as needed 1
• Starting dose: 0.3-0.5 U/kg/day for insulin-naive patients; lower doses (0.1-0.25 U/kg/day) for elderly, renal failure, or poor oral intake 1

For Patients with Poor or No Oral Intake (NPO):

Use basal-plus-correction regimen: 1

• Basal insulin: 0.1-0.25 U/kg/day 1
• Correction insulin: Rapid-acting insulin for elevated glucose 1
• No scheduled prandial insulin until nutritional intake stabilizes 1

For Critically Ill Patients:

Use continuous intravenous insulin infusion: 1

• Target range: 140-180 mg/dL for most patients 1
• Initiation threshold: Persistent hyperglycemia >180 mg/dL 1
• Protocol-driven: Use validated computerized algorithms to minimize hypoglycemia risk 1

Glycemic Targets

Recommended blood glucose ranges: 1

• Non-critically ill patients: Premeal <140 mg/dL, random <180 mg/dL 1
• Critically ill patients: 140-180 mg/dL 1
• 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

Why SSI Fails

The fundamental problem with SSI is that it treats hyperglycemia after it occurs rather than preventing it. 1 This reactive approach:

• Results in persistent hyperglycemia throughout most of the day 1
• Fails to address basal insulin requirements 1
• Has been associated with poor outcomes for over 80 years despite continued widespread use 3
• Is described in the literature as having "limited therapeutic success" and "deleterious effects" 3

Common Pitfalls to Avoid

Critical errors in inpatient glycemic management:

• Automatically placing all diabetic patients on SSI - This ignores their home regimen and physiologic insulin needs 2
• Continuing ineffective SSI without modification - If glucose remains >180 mg/dL on SSI, add basal insulin immediately 2
• Using premixed insulin (70/30) in hospital - Associated with unacceptably high hypoglycemia rates 2
• Overly aggressive targets (<140 mg/dL) - Increases hypoglycemia risk 4-6 times without additional benefit 2

Hypoglycemia Prevention

Every hospital must implement: 1

• A standardized hypoglycemia management protocol 1
• Documentation and tracking of all hypoglycemic episodes 1
• Individual prevention plans for each patient on insulin 1

The risk of iatrogenic hypoglycemia with basal-bolus regimens is 12-30% in controlled settings, making careful monitoring essential. 1

Discharge Planning

Before discharge: 1

• Resume oral medications 1-2 days before discharge if suspended during hospitalization 4
• Obtain HbA1c if not available from previous 3 months 1
• For patients with HbA1c >10%, discharge on basal-bolus regimen or previous oral agents plus 80% of hospital basal insulin dose 4
• Diet-controlled patients who required only SSI with good control can typically return to diet management alone 2