What is the recommended approach for managing hyperglycemia in hospitalized patients using a sliding scale of insulin?

Sliding Scale Insulin for Hospitalized Patients

Primary Recommendation

The sole use of sliding scale insulin (SSI) in hospitalized patients is strongly discouraged and should not be used as the primary approach for managing hyperglycemia. 1 Instead, a basal-bolus insulin regimen or basal-plus approach is the preferred treatment for most hospitalized patients with diabetes. 1, 2

Why Sliding Scale Insulin Alone Fails

• SSI treats hyperglycemia reactively rather than proactively, leading to rapid blood glucose fluctuations that worsen both hyperglycemia and hypoglycemia. 2, 3
• SSI regimens are often continued throughout hospitalization without modification, even when glycemic control remains poor. 2, 3
• Randomized trials consistently demonstrate superior outcomes with basal-bolus approaches: glycemic control (mean blood glucose <140 mg/dL) was achieved in 68% of patients receiving basal-bolus insulin versus only 38% receiving SSI alone. 2, 3
• SSI is ineffective and potentially dangerous, with studies showing it does not reduce hyperglycemia, hypoglycemia, or length of hospitalization compared to routine diabetes medications. 4, 5

Recommended Insulin Regimens by Clinical Scenario

For Non-Critically Ill Patients with Good Nutritional Intake

• Use a basal-bolus insulin regimen consisting of basal insulin plus nutritional (prandial) and correction components. 1, 3
• For insulin-naive patients or those on low insulin doses at home: start with total daily insulin dose of 0.3-0.5 units/kg, with half allocated to basal insulin (given once or twice daily) and half to rapid-acting insulin (divided three times daily before meals). 1, 2
• For patients on higher insulin doses at home (≥0.6 U/kg/day): reduce the total daily insulin dose by 20% during hospitalization to prevent hypoglycemia in patients with poor oral intake. 1, 2

For Non-Critically Ill Patients with Poor Oral Intake or NPO Status

• Use a basal-plus correction insulin regimen as the preferred treatment. 1, 3
• Administer basal insulin at 0.1-0.25 U/kg/day along with correctional doses of rapid-acting insulin for elevated glucose before meals or every 6 hours if NPO. 1, 3
• This approach is preferred for patients with mild hyperglycemia, decreased oral intake, or those undergoing surgery. 1, 3

For Critically Ill Patients

• Use continuous intravenous insulin infusion with a protocol that has demonstrated efficacy and safety. 1, 3
• Initiate insulin therapy at a threshold of no greater than 180 mg/dL (10 mmol/L), with a target glucose range of 140-180 mg/dL for the majority of critically ill patients. 1, 3

Limited Exceptions Where SSI Alone May Be Appropriate

SSI alone may be considered only in highly specific circumstances:

• Patients with mild stress hyperglycemia without a prior diagnosis of diabetes. 1, 6
• Diet-controlled type 2 diabetes patients who manage their condition without medications at home and have adequate beta-cell function. 6
• Patients with good metabolic control treated with diet alone at home, who can start with SSI alone and add basal insulin only if blood glucose consistently remains above 180 mg/dL. 1, 6

Dosing Adjustments for High-Risk Patients

Lower insulin doses should be used for patients at higher risk of hypoglycemia:

• Older patients (>65 years). 1, 2
• Patients with renal failure. 1, 2
• Patients with poor oral intake. 1, 2

Target Blood Glucose Ranges

• For non-critically ill patients: premeal blood glucose targets of <140 mg/dL with random blood glucose <180 mg/dL are reasonable, provided these targets can be safely achieved. 1
• For critically ill patients: target glucose range of 140-180 mg/dL is recommended for the majority. 1, 3

Critical Safety Considerations

• The risk of hypoglycemia with basal-bolus insulin is 4-6 times higher than with SSI alone (for blood glucose ≤70 mg/dL, risk ratio 5.75; for blood glucose ≤60 mg/dL, risk ratio 4.21). 1
• The incidence of mild iatrogenic hypoglycemia with basal-bolus approach is 12-30% in controlled settings, though this is acceptable given the superior glycemic control achieved. 1, 2
• Each hospital should adopt and implement a hypoglycemia management protocol, with a plan for preventing and treating hypoglycemia established for each patient. 1
• Premixed insulin therapy (70/30) is not recommended in the hospital due to unacceptably high rates of hypoglycemia. 1, 3

Common Pitfalls to Avoid

• Never use SSI alone for patients with type 1 diabetes—this is dangerous and should never be done. 2, 3
• Do not automatically place all diabetic patients on basal-bolus insulin regardless of their outpatient regimen, as this can lead to unnecessary hypoglycemia in diet-controlled patients. 6
• Avoid continuing the same sliding scale regimen throughout hospitalization without modification despite poor glycemic control. 2, 3
• Do not fail to adjust insulin doses when transitioning from critical to non-critical care settings. 3

Monitoring and Adjustment Strategy

• If correction doses are frequently required, increase the scheduled insulin doses accordingly. 2
• Monitor blood glucose before meals and at bedtime (or every 4-6 hours if NPO). 6
• During changes to a patient's insulin regimen, increase the frequency of blood glucose monitoring. 7