What is the sliding scale for insulin dosing starting at a blood glucose level of 120 mg/dL?

Sliding Scale Insulin Starting at 120 mg/dL Should Not Be Used as Monotherapy

Sliding scale insulin alone is strongly discouraged for hospitalized patients because it treats hyperglycemia reactively, leading to poor glycemic control and rapid glucose fluctuations that worsen both hyper- and hypoglycemia. 1, 2 Instead, use a basal-bolus regimen or basal-plus approach with correction doses.

Why Sliding Scale Alone Fails

• Sliding scale insulin is associated with clinically significant hyperglycemia and achieves glycemic control in only 38% of patients compared to 68% with basal-bolus regimens 1, 2
• This reactive approach creates rapid blood glucose fluctuations rather than preventing hyperglycemia 1
• The American Diabetes Association strongly discourages sole use of sliding scale insulin in hospitalized patients due to its ineffectiveness 2

Recommended Approach Instead

Start with a basal-bolus regimen: 0.3-0.5 units/kg total daily dose, divided 50% as basal insulin (once daily) and 50% as prandial insulin (before meals), plus correction doses for hyperglycemia. 1

For Patients with Good Oral Intake:

• Calculate total daily dose: 0.3-0.5 units/kg 1
• Give 50% as long-acting basal insulin (glargine, detemir, or degludec) once daily 2
• Give 50% divided as rapid-acting insulin (lispro, aspart, or glulisine) before each meal 2
• Add correction doses using the scale below 1, 2

For Patients with Poor Oral Intake or NPO:

• Use basal-plus approach: 0.1-0.25 units/kg/day of basal insulin only 1
• Add correction doses of rapid-acting insulin for hyperglycemia 1

Correction Dose Scale (As Adjunct Only)

For premeal glucose >250 mg/dL: give 2 units of rapid-acting insulin 2

For premeal glucose >350 mg/dL: give 4 units of rapid-acting insulin 2

• Never use rapid-acting insulin at bedtime due to nocturnal hypoglycemia risk 2
• Target premeal glucose of 90-150 mg/dL in most patients 2

When Sliding Scale Alone Might Be Acceptable

The following limited scenarios are the only situations where sliding scale insulin alone may be reasonable 2:

• Patients with HbA1c <7% on diet or minimal home therapy with only mild hyperglycemia 1, 2
• Patients who are NPO with no nutritional replacement and only mild hyperglycemia 1, 2
• Patients newly started on or tapering off corticosteroids 1, 2
• Patients with mild stress hyperglycemia without pre-existing diabetes 1, 2

Dose Adjustments for High-Risk Patients

• Use lower doses (0.1-0.25 units/kg) for patients at higher risk of hypoglycemia: older patients, those with renal failure (eGFR <30), or those with unpredictable oral intake 1, 3
• Reduce total daily dose by 20% during hospitalization for patients on high insulin doses at home (≥0.6 units/kg/day) 1
• Patients with renal failure have 4-6 times higher risk of hypoglycemia and require lower insulin doses 3

Critical Monitoring

• If correction doses are frequently required, increase the scheduled basal and prandial insulin doses rather than continuing to rely on sliding scale 2
• Monitor blood glucose before meals and at bedtime 3
• Target conventional glucose range of 140-180 mg/dL for most hospitalized patients 1
• Maintaining blood glucose <180 mg/dL minimizes symptoms without adversely affecting outcomes 4

Common Pitfalls to Avoid

• Never use premixed insulin (70/30) in hospitals due to unacceptably high hypoglycemia rates 1
• Do not abruptly discontinue oral medications when starting insulin due to risk of rebound hyperglycemia 5
• Basal-bolus approach carries 12-30% risk of hypoglycemia in controlled settings, so have a clear hypoglycemia treatment plan 1, 3