Can patients with type 1 diabetes use scheduled meal time insulin with a sliding scale?

Scheduled Mealtime Insulin with Sliding Scale in Type 1 Diabetes

Sliding scale insulin alone should NOT be used as the primary insulin regimen for patients with type 1 diabetes; instead, a basal-bolus regimen with scheduled mealtime insulin plus correction doses (not traditional sliding scale) is the recommended approach. 1

Why Sliding Scale Alone Fails in Type 1 Diabetes

Prolonged use of sliding scale insulin regimens as the sole treatment is strongly discouraged because it treats hyperglycemia reactively rather than proactively, leading to poor glycemic control and increased complications. 1

• Sliding scale insulin causes rapid blood glucose fluctuations that worsen both hyperglycemia and hypoglycemia 2
• This reactive approach fails to provide the basal insulin that patients with type 1 diabetes absolutely require to prevent ketoacidosis 1
• Randomized controlled trials demonstrate that basal-bolus treatment improves glycemic control and reduces hospital complications compared to sliding scale regimens 1

The Correct Approach: Basal-Bolus with Correction Doses

For type 1 diabetes, use a scheduled basal-bolus insulin regimen where mealtime insulin is matched to carbohydrate intake, supplemented by correction doses for hyperglycemia. 1, 2

Outpatient/Ambulatory Setting

• Patients should learn carbohydrate counting or another meal planning approach to match mealtime insulin to carbohydrates consumed 1
• On multiple daily injection plans or insulin pumps: take mealtime insulin 15-20 minutes before eating, with meals consumed at flexible times 1, 3
• Rapid-acting insulin analogues administered 15-20 minutes pre-meal reduce post-meal glucose levels by approximately 30% compared to immediate pre-meal dosing 3
• If on premixed insulin: doses must be taken at consistent times daily, meals consumed at similar times, and meals should not be skipped to reduce hypoglycemia risk 1

Inpatient/Hospital Setting

An insulin regimen with basal, prandial, and correction components is the preferred treatment for hospitalized type 1 diabetes patients with good nutritional intake. 1

• For patients eating meals: insulin injections should align with meals, with point-of-care glucose testing performed immediately before meals 1
• If oral intake is poor: administer prandial insulin immediately after the patient eats, with dose adjusted for the amount ingested 1
• Basal insulin must be continued even if feedings are discontinued to prevent ketoacidosis in type 1 diabetes 1

When Correction Doses (Modified Sliding Scale) Are Appropriate

Correction doses of rapid- or short-acting insulin should be used to address hyperglycemia, but only as a supplement to scheduled basal and prandial insulin—never as monotherapy. 1, 2

• Subcutaneous rapid- or short-acting insulin before meals, or every 4-6 hours if not eating, is indicated to correct hyperglycemia 1
• If correction doses are frequently required, increase the scheduled insulin doses accordingly rather than continuing to rely on corrections 2
• For patients with renal impairment, use a modified correction scale with lower doses due to 4-6 times higher hypoglycemia risk 4

Calculating Initial Insulin Doses

Start with total daily insulin dose of 0.3-0.5 units/kg, divided 50% as basal insulin and 50% as prandial insulin distributed across meals. 2

• Use lower doses (0.1-0.25 units/kg/day) for patients at higher hypoglycemia risk: elderly, renal failure, poor oral intake 2, 4
• For patients already on high home insulin doses (≥0.6 units/kg/day), reduce total daily dose by 20% during hospitalization to prevent hypoglycemia 2

Critical Pitfalls to Avoid

• Never use sliding scale insulin as monotherapy in type 1 diabetes—these patients require continuous basal insulin to prevent diabetic ketoacidosis 1
• Avoid premixed insulin formulations in the hospital setting due to unacceptably high hypoglycemia rates (despite comparable glycemic control) 1, 2
• Do not continue sliding scale regimens throughout hospital stays without modification when control remains poor 2
• Coordinate meal delivery with nutritional insulin coverage, as variability creates hyperglycemic and hypoglycemic events 1