2326-PUB: The Correction Factor (CF) and Carbohydrate-to-Insulin Ratio (CIR) Are More Correlated to Each Other than to the Total Daily Dose (TDD)

Abstract

The accepted bolus dosing factor estimation formulas are CIR = 450/TDD and CF = 1700/TDD. These formulas were not based on controlled studies. We have combined two of our previously published well-controlled studies to reevaluate these relationships. Both studies (30 pump treated T1DM and 11 pump- or multiple daily dose-treated T1 or 2 subjects) established the basal insulin dose by frequent glucose testing while on a controlled diet and meal omissions to assess the post-meal period. Then CIR was determined by the return of the 2-4 h post meal plasma glucose (PG) to ± 20% of the pre-meal and the CF was independently determined by greatest PG reduction during the 2-4th hour after a corrective bolus following hyperglycemia induced by a reduction (about 30%) of the basal insulin. CIR = CF/4.49 (r = 0.940), CIR = 295/TDD (r =0.720) and CIR = 107/TBD (r = 0.7310). The strong relationship between CIR and CF may be explained by CF is a measure of the ∆ PG/U and CIR is a measure of the anticipated ∆ PG/U and both are expressions of the insulin sensitivity of the same tissue bed. If one bolus dosing factor is established, the other could better be estimated using CF = CIR*4.5 than from TDD. The usual order of titration is TBD, then CIR and CF and finally TDD is calculated. After TBD is established and before bolus dosing factors and TDD, CIR = 100/TBD would be a better estimate than 450/TDD. Disclosure J. Socha: None. A.B. King: None.