How to Start a Sliding Scale for Lispro Insulin
Sliding scale insulin (SSI) as a sole method should be avoided for glycemic control in hospitalized patients with diabetes. Instead, use correction insulin as part of a scheduled insulin regimen that includes basal and/or prandial components 1.
Understanding the Terminology
The term "sliding scale" is outdated and refers to reactive insulin dosing without regard to meals or individual insulin sensitivity. Modern practice uses correction insulin (also called supplemental insulin) as an adjunct to scheduled insulin therapy, not as standalone treatment 1.
Recommended Approach: Correction Insulin Scale
For hospitalized patients, use the following correction insulin scale with rapid-acting insulin lispro 1:
Dosing Table
| Blood Glucose (mg/dL) | Insulin-Sensitive | Usual | Insulin-Resistant |
|---|---|---|---|
| 141-180 | 2 units | 4 units | 6 units |
| 181-220 | 4 units | 6 units | 8 units |
| 221-260 | 6 units | 8 units | 10 units |
| 261-300 | 8 units | 10 units | 12 units |
| 301-350 | 10 units | 12 units | 14 units |
| 351-400 | 12 units | 14 units | 16 units |
| ≥400 | 14 units | 16 units | 18 units |
Column Selection Guidelines 1:
- Insulin-sensitive column: Elderly patients, those not eating, patients with impaired renal function (GFR <60 mL/min)
- Usual column: Standard starting point for most patients who are eating
- Insulin-resistant column: Patients on corticosteroids, those previously requiring >80 units/day
Administration Timing 1:
- If eating: Give before each meal following the appropriate column
- If NPO (not eating): Give every 4-6 hours using the insulin-sensitive column
- At bedtime: Give half the supplemental insulin dose
Critical Implementation Points
This correction insulin must be combined with scheduled basal insulin 1. The recommended approach:
Basal Insulin Component:
- Start 0.2-0.3 units/kg/day for patients ≥70 years or GFR <60 mL/min
- Start 0.4 units/kg/day for blood glucose 140-200 mg/dL
- Start 0.5 units/kg/day for blood glucose 201-400 mg/dL
- Give 50% as basal insulin (glargine, detemir, or NPH)
- Give 50% as prandial insulin lispro divided before meals 1
For Older Adults Simplification 2, 3:
While adjusting prandial insulin, a simplified sliding scale may be used temporarily:
- Premeal glucose >250 mg/dL: give 2 units lispro
- Premeal glucose >350 mg/dL: give 4 units lispro
- Stop this simplified scale when not needed daily 2, 3
Common Pitfalls to Avoid
- Never use SSI as monotherapy - This approach results in unacceptable hyperglycemia and increased risk of complications 1
- Don't ignore scheduled insulin - Correction insulin addresses current hyperglycemia but doesn't prevent future episodes
- Adjust the regimen - If correction insulin is needed repeatedly, increase the scheduled basal or prandial doses by 10-20% 1
- Monitor for hypoglycemia - If blood glucose <80 mg/dL occurs ≥2 times/week, decrease insulin doses by 2 units or 10-20% 1
Outpatient Context
For outpatient type 2 diabetes, the modern approach prioritizes scheduled basal-bolus therapy rather than correction-only regimens 4, 5. Start prandial lispro at 4 units per meal or 10% of basal dose, then titrate by 1-2 units twice weekly based on premeal and 2-hour postprandial glucose values 4, 5.
The evidence strongly supports that scheduled insulin regimens with correction doses produce superior glycemic control compared to sliding scale monotherapy, with similar or lower hypoglycemia rates 1.