Is the primary purpose of switching patients from oral hypoglycemic agents (OHAs) to a sliding scale insulin regimen while inpatient to decrease hypoglycemia risk?

Switching from Oral Hypoglycemic Agents to Sliding Scale Insulin in Hospital: Not Primarily for Hypoglycemia Prevention

Switching patients from oral hypoglycemic agents (OHAs) to sliding scale insulin while inpatient is NOT primarily to decrease hypoglycemia risk. In fact, the sole use of sliding scale insulin in the inpatient hospital setting is strongly discouraged as it can lead to poor glycemic control and adverse outcomes. 1

Preferred Inpatient Insulin Regimens

• Basal insulin or a basal plus bolus correction insulin regimen is the preferred treatment for noncritically ill hospitalized patients with poor oral intake or those who are taking nothing by mouth (NPO) 1
• An insulin regimen with basal, prandial, and correction components is the preferred treatment for noncritically ill hospitalized patients with good nutritional intake 1
• Prolonged sole use of sliding scale insulin in the inpatient hospital setting is strongly discouraged due to poor glycemic control and increased risk of complications 1, 2

Problems with Sliding Scale Insulin

• Sliding scale insulin alone is reactive rather than preventive, responding to hyperglycemia after it occurs rather than preventing it 1, 3
• Studies have shown that sliding scale insulin regimens are often ineffectual and prone to deficiencies in monitoring, documentation, and prescribing soundness 2
• Only about 12% of sliding scale insulin injections successfully bring elevated blood glucose values to within target range 2

Hypoglycemia Risk with Different Regimens

• Basal-bolus insulin regimens are associated with better glycemic control but may have a higher risk of hypoglycemia compared to sliding scale insulin alone 4
• The estimated risk of hypoglycemia with basal-bolus insulin is about 4-6 times higher than with sliding scale insulin therapy 1
• Premixed insulin therapy (human insulin 70/30) has been associated with an unacceptably high rate of iatrogenic hypoglycemia and is not recommended in the hospital 1

Appropriate Inpatient Diabetes Management

• For most hospitalized patients with diabetes, oral antihyperglycemic medications should be held during hospitalization 1
• If oral medications are held in the hospital, there should be a protocol for resuming them 1–2 days before discharge 1
• In certain circumstances, it may be appropriate to continue home regimens including oral antihyperglycemic medications, particularly for patients with mild hyperglycemia and good metabolic control 1

Recommendations for Inpatient Glycemic Control

• Target blood glucose range of 140-180 mg/dL is recommended for most hospitalized patients 1, 5
• For patients with type 1 diabetes, an insulin regimen with basal and correction components is necessary, with the addition of prandial insulin if the patient is eating 1
• A hypoglycemia management protocol should be adopted and implemented by each hospital to prevent and treat hypoglycemia 1

Why OHAs are Often Discontinued in Hospital

• Risk of adverse effects in acute illness (e.g., metformin and risk of lactic acidosis in patients with renal impairment, hypoxia, or sepsis) 1
• Unpredictable absorption and effect during acute illness 1
• Potential drug interactions with other medications administered during hospitalization 1
• Need for more precise and rapid glycemic control during acute illness 6

In conclusion, the transition from OHAs to insulin in the hospital setting is primarily to achieve better glycemic control during acute illness, not specifically to reduce hypoglycemia risk. When insulin is required, a basal-bolus regimen is preferred over sliding scale insulin alone for most patients.