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

Why SSI Fails: The Evidence

SSI treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations that exacerbate both hyper- and hypoglycemia. 1, 2 The approach is fundamentally flawed because:

• SSI achieved glycemic control (mean blood glucose <140 mg/dL) in only 38% of patients versus 68% with basal-bolus insulin 3
• Insulin effects were subtherapeutic after 84% of SSI injections, with glucose levels remaining persistently elevated 4
• Only 6% of patients on SSI attained good glycemic control through 5 days of therapy 4
• SSI regimens were never adjusted in 81% of patients despite persistently elevated glucose levels 4

The Recommended Alternative: Basal-Bolus Insulin

For Patients Eating Regular Meals

Start with a total daily dose of 0.3-0.5 units/kg/day, divided as 50% basal insulin (once daily) and 50% prandial insulin (split before meals). 1, 2

For example, a 70 kg patient would receive:

• Total daily dose: 21-35 units
• Basal insulin (glargine or detemir): 10-17 units once daily
• Prandial insulin (aspart or lispro): 3-6 units before each of three meals 2

For Patients with Poor Oral Intake or NPO

Use a basal-plus approach: 0.1-0.25 units/kg/day of basal insulin plus correction doses of rapid-acting insulin for hyperglycemia. 1, 2, 5

This provides continuous background insulin coverage while allowing flexibility for variable nutritional intake. 2

Titration Protocol

• Adjust basal insulin every 3 days based on fasting glucose patterns, targeting 80-130 mg/dL 3
• Adjust prandial insulin by 1-2 units every 3 days based on 2-hour postprandial glucose, targeting <180 mg/dL 3
• Check point-of-care glucose before each meal and at bedtime for patients eating regular meals 3
• For patients with poor oral intake, check glucose every 4-6 hours 3

When SSI Might Be Acceptable (Very Limited Circumstances)

SSI as monotherapy may be appropriate ONLY for: 2, 5

1. Patients without pre-existing diabetes who develop mild stress hyperglycemia during hospitalization 2, 5
2. Well-controlled type 2 diabetes patients (HbA1c <7%) on diet alone or minimal oral therapy at home who have mild hyperglycemia 2, 5
3. Patients who are NPO with no nutritional replacement and only mild hyperglycemia 2
4. Patients who are new to steroids or tapering steroids 2

Critical Safety Considerations

Hypoglycemia Risk

Basal-bolus regimens carry a 4-6 times higher risk of hypoglycemia compared to SSI alone (RR 5.75 for blood glucose ≤70 mg/dL). 5 However, this increased risk is acceptable given the superior glycemic control and reduced complications. 2

For high-risk patients (elderly >65 years, renal failure, poor oral intake), reduce the starting dose to 0.1-0.25 units/kg/day. 1, 3, 2

Dose Reduction for Patients on High Home Insulin

For patients on high-dose insulin at home (≥0.6 units/kg/day), reduce the total daily dose by 20% during hospitalization to prevent hypoglycemia. 3, 2, 5

Common Pitfalls to Avoid

• Never use SSI as monotherapy for patients with type 1 diabetes—this is associated with clinically significant hyperglycemia 2
• Never give rapid-acting insulin at bedtime—this significantly increases nocturnal hypoglycemia risk 3, 6
• Never continue premixed insulin (70/30) in hospitals—randomized trials show unacceptably high hypoglycemia rates 3, 2
• Never abruptly discontinue oral medications when starting insulin—this risks rebound hyperglycemia 7
• If correction doses are frequently required, increase the scheduled insulin doses accordingly rather than continuing SSI alone 2

Target Glucose Ranges

Target a conventional glucose range of 140-180 mg/dL for most non-critically ill hospitalized patients. 1, 2 More stringent targets (110-140 mg/dL) may be appropriate for cardiac surgery patients if achievable without significant hypoglycemia. 1

Monitoring Requirements

Self-monitoring of blood glucose plays an essential role in the prevention and management of hypoglycemia; increased frequency of blood glucose monitoring is recommended in patients at higher risk for hypoglycemia. 6