From the Guidelines
1 unit of short-acting insulin typically lowers blood glucose by 30-50 mg/dL, but a commonly used estimate is 1 unit lowering blood glucose by 50 mg/dL. This conversion factor is crucial for managing blood sugar levels effectively. When adjusting prandial insulin, a simplified sliding scale may be used, for example, giving 2 units of short- or rapid-acting insulin for premeal glucose >250 mg/dL (>13.9 mmol/L) 1.
- Key factors influencing the correction factor include body weight, insulin sensitivity, time of day, physical activity, stress levels, and concurrent illness.
- To determine a personal correction factor, a formula such as dividing 1800 by the total daily insulin dose for rapid-acting insulin or 1500 for Regular insulin can be used, but this should be adjusted based on observed responses and in consultation with a healthcare provider 1.
- The goal is to achieve premeal glucose levels between 90–150 mg/dL (5.0–8.3 mmol/L), and adjustments to insulin dose or the addition of other glucose-lowering agents should be made every 2 weeks based on finger-stick glucose testing 1.
- It's essential to work closely with a healthcare provider to establish a specific insulin sensitivity factor, as using an incorrect factor could lead to dangerous high or low blood sugar episodes.
From the Research
Safe Conversion for Short Acting Insulin
- The provided studies do not directly address the question of how much 1 unit of short-acting insulin should decrease blood sugar levels 2, 3, 4, 5, 6.
- However, the studies compare the efficacy and safety of different rapid-acting insulin analogs, such as insulin lispro and insulin aspart, in patients with type 1 and type 2 diabetes mellitus 3, 4, 5, 6.
- These studies suggest that insulin lispro and insulin aspart have comparable efficacy and safety in controlling prandial glycemic excursions, with similar decreases in glycated hemoglobin (HbA1c) and similar dosing and weight changes 3, 4, 6.
- However, there is no direct information on the specific decrease in blood sugar levels per unit of short-acting insulin administered.
General Guidance on Insulin Dosing
- The studies emphasize the importance of individualized insulin dosing and titration to achieve optimal glycemic control 2, 3, 4, 5, 6.
- Healthcare providers should consider factors such as the patient's insulin sensitivity, diet, and physical activity level when determining the appropriate insulin dose 2, 5.
- The American Diabetes Association and other organizations provide general guidelines for insulin dosing, but these may need to be adjusted based on individual patient factors 2, 5.