How do you initiate sliding scale insulin (SSI) therapy in a typical adult patient with type 2 diabetes mellitus (T2DM)?

How to Start Sliding Scale Insulin

Do Not Use Sliding Scale Insulin (SSI) as Monotherapy

Sliding scale insulin alone should not be used as the initial or sole approach for managing hyperglycemia in hospitalized patients with diabetes. 1, 2 This practice is explicitly condemned by all major diabetes guidelines and has been shown to be ineffective. 3, 4

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Why SSI Alone Fails

• SSI treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations and poor glycemic control. 3, 1
• Randomized trials consistently demonstrate that basal-bolus insulin regimens achieve superior glycemic control (68% achieving mean blood glucose <140 mg/dL) compared to SSI alone (38%). 1
• SSI regimens are often continued throughout hospital stays without modification, even when control remains poor. 1
• The medical literature uniformly supports that SSI is an ineffective means to control blood glucose concentrations. 5, 4

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The Correct Approach: Scheduled Basal-Bolus Insulin

Initial Dosing for Hospitalized Patients

For insulin-naive patients or those on low-dose home insulin:

• Start with a total daily dose of 0.3-0.5 units/kg, divided as 50% basal insulin (once daily) and 50% prandial insulin (divided before meals). 1, 3
• For patients at higher risk of hypoglycemia (elderly >65 years, renal failure, poor oral intake), use lower doses of 0.1-0.25 units/kg/day. 1, 3

For patients already on high-dose home insulin (≥0.6 units/kg/day):

• Reduce the total daily dose by 20% upon hospitalization to prevent hypoglycemia. 1, 3

Specific Regimen Structure

• Basal insulin: Give 50% of total daily dose as long-acting insulin (glargine or detemir) once daily. 1, 3
• Prandial insulin: Divide the remaining 50% equally among three meals as rapid-acting insulin (lispro, aspart, or glulisine) given 0-15 minutes before meals. 1, 3
• Correction doses: Add supplemental rapid-acting insulin for premeal glucose >180 mg/dL using a simplified scale: 2 units for glucose >250 mg/dL, 4 units for glucose >350 mg/dL. 1, 6

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When SSI Might Be Acceptable (Rare Situations)

SSI as an adjunct (not monotherapy) may be appropriate only in these limited scenarios:

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

Even in these situations, correction insulin should be used as a supplement to scheduled basal insulin, not as the sole therapy. 1

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Monitoring and Titration

• Check point-of-care glucose before each meal and at bedtime for patients eating regular meals. 3
• Target glucose range: 140-180 mg/dL for most non-critically ill hospitalized patients. 1, 3
• If correction doses are frequently required, increase the scheduled insulin doses accordingly rather than continuing to rely on SSI. 1
• Titrate basal insulin every 3 days based on fasting glucose patterns, targeting 80-130 mg/dL. 3
• Adjust prandial insulin by 1-2 units every 3 days based on 2-hour postprandial glucose readings, targeting <180 mg/dL. 3

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Critical Pitfalls to Avoid

• Never use SSI as monotherapy—it leads to poor glycemic control and increased complications. 1, 2
• Never give rapid-acting insulin at bedtime to avoid nocturnal hypoglycemia. 3, 6
• Avoid premixed insulin (70/30) in hospitals due to unacceptably high hypoglycemia rates. 1, 3
• Do not continue SSI regimens without modification when control remains poor. 1
• Never abruptly discontinue oral medications (especially metformin) when starting insulin therapy. 7

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Evidence Supporting Basal-Bolus Over SSI

• Basal-bolus insulin reduces postoperative complications including wound infections and acute renal failure compared to SSI. 1
• Glycemic control is achieved in 68% of patients on basal-bolus versus only 38% on SSI alone. 1
• SSI is associated with clinically significant hyperglycemia and should not be used as the initial approach. 7, 2
• A 70/30 insulin algorithm achieves superior glycemic control compared to traditional SSI dosing (p=0.042). 5