What is a suitable prescriber template for sliding scale insulin in a patient with diabetes?

Sliding Scale Insulin Should Not Be Used as Monotherapy in Hospitalized Patients

Sliding scale insulin (SSI) alone is strongly discouraged for hospitalized patients with diabetes and should be replaced with a basal-bolus or basal-plus regimen, except in very limited circumstances such as patients without pre-existing diabetes who develop mild stress hyperglycemia. 1, 2

Why Sliding Scale Insulin Fails

Traditional SSI regimens are ineffective and potentially harmful because they:

• Treat hyperglycemia reactively after it has already occurred, rather than preventing it 1
• Lead to rapid blood glucose fluctuations that exacerbate both hyperglycemia and hypoglycemia 1, 2
• Are typically prescribed on admission and continued without modification throughout hospitalization, even when control remains poor 1, 2
• Result in only 38% of patients achieving glycemic control (mean blood glucose <140 mg/dL) compared to 68% with basal-bolus therapy 1, 3

Recommended Alternative: Basal-Bolus or Basal-Plus Regimen

For Insulin-Naive Patients or Those on Low Doses:

Starting dose: 0.3-0.5 units/kg/day total daily dose 1, 2

Distribution:

• 50% as basal insulin (glargine or detemir) given once daily 1, 2
• 50% as rapid-acting insulin (lispro, aspart, or glulisine) divided before three meals 1, 2

Example for a 70 kg patient:

• Total daily dose: 21-35 units
• Basal insulin: 10-18 units once daily
• Rapid-acting insulin: 3-6 units before each meal 2

For High-Risk Patients (Elderly, Renal Failure, Poor Oral Intake):

Use lower doses: 0.1-0.25 units/kg/day 1, 2

For Patients Already on High-Dose Insulin at Home (≥0.6 units/kg/day):

Reduce total daily dose by 20% during hospitalization to prevent hypoglycemia 1, 2

Correction Dose Template (Supplemental to Scheduled Insulin)

Add correction doses of rapid-acting insulin before meals or every 4-6 hours if NPO: 1, 2

• Blood glucose 151-200 mg/dL: 2 units
• Blood glucose 201-250 mg/dL: 4 units
• Blood glucose 251-300 mg/dL: 6 units
• Blood glucose 301-350 mg/dL: 8 units
• Blood glucose >350 mg/dL: 10 units and notify physician 2

Critical point: If correction doses are frequently required, increase the scheduled basal or prandial insulin doses accordingly rather than continuing to rely on corrections 1, 2

Very Limited Acceptable Uses of SSI Alone

SSI as monotherapy may be appropriate only for: 2, 4

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

Evidence Supporting This Approach

The RABBIT 2 trial demonstrated that basal-bolus therapy achieved target blood glucose <140 mg/dL in 66% of patients versus only 38% with SSI, with an overall blood glucose difference of 27 mg/dL (P<0.01) 3. The basal-bolus approach was also associated with reduced complications including postoperative wound infection, pneumonia, bacteraemia, and acute renal failure 1.

Critical Pitfalls to Avoid

• Never use SSI alone in patients with type 1 diabetes - this can lead to diabetic ketoacidosis 2, 5
• Avoid premixed insulin (70/30) in hospitals due to unacceptably high hypoglycemia rates 2, 4
• Do not abruptly discontinue oral medications when starting insulin due to risk of rebound hyperglycemia 6
• Monitor for hypoglycemia: Basal-bolus regimens carry a 4-6 times higher risk of hypoglycemia (blood glucose ≤70 mg/dL) compared to SSI, though severe hypoglycemia rates are similar 4, 7

Target Glucose Range

Aim for 140-180 mg/dL for most hospitalized patients 1