Current Guidelines on Sliding Scale Insulin in Hospitalized Patients
The sole use of sliding scale insulin (also called correction or supplemental insulin without basal insulin) in hospitalized patients is strongly discouraged and should be discontinued. 1
Why Sliding Scale Insulin Alone Fails
The evidence against sliding scale insulin as monotherapy is overwhelming and consistent across multiple guideline iterations:
Sliding scale insulin (SSI) alone results in significantly worse glycemic control, with meta-analysis showing a mean blood glucose difference of 27.33 mg/dL higher compared to basal-bolus regimens, along with increased hyperglycemic events. 2
SSI is a reactive rather than proactive approach that doses insulin based solely on current glucose levels without accounting for basal insulin requirements, caloric intake, or insulin resistance—leading to both hyperglycemia and hypoglycemia. 1
Real-world effectiveness is dismal: Studies show only 6-12% of patients achieve good glycemic control with SSI, with 51-68% remaining poorly controlled throughout hospitalization. 3
The Correct Approach: Basal-Bolus-Correction Regimens
For Noncritically Ill Patients Eating Meals
Use a three-component insulin regimen consisting of basal, prandial (bolus), and correction insulin. 1, 4
Basal insulin (glargine, detemir, or degludec) provides 24-hour background coverage, typically dosed once daily at 0.1-0.25 units/kg/day for insulin-naive patients. 4, 5
Prandial insulin (rapid-acting analogs: lispro, aspart, or glulisine) is given before each meal to cover nutritional intake. 4, 6
Correction insulin (same rapid-acting analog) is added to prandial doses to correct elevated pre-meal glucose levels. 4, 5
For Noncritically Ill Patients NPO or With Poor Oral Intake
Use basal insulin plus correction insulin only (no prandial component). 1, 4
Administer basal insulin at a reduced dose (typically 60-80% of usual dose or 0.1-0.25 units/kg/day). 7, 4
Add correction doses of rapid-acting insulin every 4-6 hours based on glucose monitoring. 7, 4
Critical pitfall to avoid: Never use correction insulin alone without basal insulin in NPO patients—this is the sliding scale approach that guidelines explicitly discourage. 1, 7
For Critically Ill Patients
Continuous intravenous insulin infusion is the preferred method, with target glucose range of 140-180 mg/dL for most patients. 1
Use validated written or computerized protocols that allow predefined adjustments based on glycemic fluctuations. 1
More aggressive targets (110-140 mg/dL) may be appropriate for select stable patients, but targets below 110 mg/dL increase mortality and should be avoided. 1, 5
Monitoring Requirements
For patients on IV insulin: Monitor every 30 minutes to 2 hours. 5
Transitioning from IV to Subcutaneous Insulin
Administer subcutaneous basal insulin 2-4 hours before discontinuing IV insulin to prevent rebound hyperglycemia. 1, 4
Calculate the subcutaneous basal dose at 60-80% of the 24-hour IV insulin requirement based on the last 6-8 hours of stable infusion. 1, 4
This transition protocol reduces morbidity and hospital costs compared to abrupt discontinuation. 4
Special Considerations for Type 1 Diabetes
Patients with type 1 diabetes must never have basal insulin discontinued, even when NPO, as this risks diabetic ketoacidosis. 1, 4
- Dosing insulin based solely on premeal glucose (the sliding scale approach) is particularly dangerous in type 1 diabetes, as it ignores absolute basal insulin requirements. 1
Common Pitfalls to Avoid
Never use sliding scale insulin as the sole regimen—this has been explicitly discouraged in every ADA guideline since 2015. 1
Don't confuse correction insulin with sliding scale insulin: Correction insulin is appropriate as part of a comprehensive regimen, but not as monotherapy. 1
Avoid premixed insulin formulations (70/30,75/25) in the hospital, as they significantly increase hypoglycemia risk compared to basal-bolus regimens. 1, 4
Document and track all hypoglycemic episodes (glucose <70 mg/dL), as 84% of patients with severe hypoglycemia had a prior episode during the same admission. 4, 5
The Bottom Line
The 2024 American Diabetes Association guidelines represent the culmination of decades of evidence showing that sliding scale insulin alone is ineffective and potentially harmful. 1 The practice has been used for over 80 years without evidence supporting it as standard of care, and meta-analyses confirm it provides no benefits while increasing hyperglycemic events. 2, 8 Modern insulin management requires a proactive, physiologic approach using basal insulin as the foundation, with prandial and correction components added based on nutritional intake.