346-OR: In Young People with T1D, Additional Mealtime Insulin Produces a Dose-Dependent Improvement in Glycemia after a High-Fat, High-Protein Meal

Background: To manage hyperglycemia following high fat and protein (HFHP) meals, T1D guidelines recommend additional mealtime insulin. However, guidance regarding dosing adjustments for HFHP meals is unclear. Aim: To determine the amount of additional insulin required for a HFHP meal to optimise 6 h postprandial glucose, in young people with T1D using insulin pumps. Method: This was a 4x4 crossover trial conducted at 2 centers in Australia. On 4 days, participants (n=27) with mean age 14.5 ± 3.6 yrs and HbA1c 53 mmol/mol (7.0 ± 0.7%) ate a HFHP meal [carbohydrate (CHO) 30g, fat 40g, protein 50g]. Insulin based on the CHO: insulin ratio (CIR) was given in random order: 100% (control), 120%, 140%, 160% CIR. Postprandial sensor glucose was measured for 6 h. Results: Compared to 100% CIR, 140% and 160% CIR resulted in significantly lower mean glucose excursions from 90- 360 min (p≤ 0.018) and mean peak glucose excursions (4.0 and 2.7 v 6.0 mmol/L, p< 0.001). Hypoglycemia for 100%- 160% CIR was 7.7%, 7.7%, 12.0% and 19.2% respectively (p≥ 0.139). With increasing insulin there was a dose-dependent reduction in mean glucose excursions from 60- 360 min (p< 0.01). Conclusions: Incremental addition of mealtime insulin for fat and protein produces a dose- dependent improvement in postprandial glycemia. For HFHP meals, 140% CIR is advised with titration based on individual glucose response.