Is inpatient sliding scale insulin therapy necessary for a patient with diet-controlled type 2 diabetes (DM 2) who is not taking medications?

Sliding Scale Insulin for Diet-Controlled Type 2 Diabetes Inpatients

For patients with diet-controlled type 2 diabetes who are not taking medications at home, sliding scale insulin alone is appropriate for inpatient management, with basal insulin added only if glucose levels remain persistently above 180 mg/dL despite correctional insulin. 1, 2

Assessment of Inpatient Insulin Requirements

• Patients with diet-controlled diabetes who manage their condition without medications at home typically have adequate beta-cell function and do not require scheduled basal insulin during hospitalization 1
• The use of sliding scale insulin alone may be appropriate for patients with mild stress hyperglycemia or those with good metabolic control treated with diet alone at home 1
• Current guidelines strongly discourage the sole use of sliding scale insulin for patients with established insulin requirements, but this recommendation does not necessarily apply to diet-controlled patients 1

Recommended Approach

• For diet-controlled type 2 diabetes patients:

  • Begin with sliding scale insulin (correctional insulin) alone to treat hyperglycemia after it occurs 1, 2
  • Monitor blood glucose before meals and at bedtime (or every 4-6 hours if NPO) 1
  • Add basal insulin only if blood glucose levels consistently remain above 180 mg/dL despite correctional insulin 1, 2

• If basal insulin becomes necessary:

  • Start with a low dose (0.1-0.25 U/kg per day) along with correctional insulin 1
  • This "basal-plus" approach is preferred over full basal-bolus regimens for patients with mild hyperglycemia 1

Evidence Supporting This Approach

• Guidelines recognize that sliding scale insulin alone may be appropriate for patients without diabetes or those with mild stress hyperglycemia 1
• For patients with good metabolic control treated with diet alone at home, sliding scale insulin alone is recommended as the initial approach 1, 2
• The risk of hypoglycemia with basal-bolus insulin is 4-6 times higher than with sliding scale insulin therapy alone, making the latter safer for patients who don't require insulin at home 1

Common Pitfalls to Avoid

• Automatically placing all diabetic patients on basal-bolus insulin regimens regardless of their outpatient regimen can lead to unnecessary hypoglycemia 1
• Continuing the same sliding scale regimen throughout hospitalization without modification despite poor control 1, 2
• Using premixed insulin therapy (70/30) in the hospital setting, which has been associated with unacceptably high rates of hypoglycemia 1
• Failing to monitor glucose levels appropriately - for patients who are eating, glucose monitoring should be performed before meals; for those not eating, every 4-6 hours 1

Special Considerations

• If the patient develops persistent hyperglycemia (>180 mg/dL) despite sliding scale insulin:
  • Add a low dose of basal insulin (0.1-0.25 U/kg/day) 1
  • Continue to monitor and adjust as needed 1
• For patients with renal impairment, use lower doses of insulin due to increased risk of hypoglycemia 3
• If the patient has significant stress (surgery, infection, steroids), they may temporarily require more intensive insulin therapy despite being diet-controlled at home 1

Transition to Discharge

• For diet-controlled patients who required only sliding scale insulin during hospitalization with good glycemic control, they can typically return to diet management alone upon discharge 1
• If basal insulin was required during hospitalization but the patient was previously diet-controlled, reassess the need for continued medication before discharge 1