INTRA-INDIVIDUAL VARIABILITY IN SUBCUTANEOUS INSULIN ABSORPTION DURING HYBRID CLOSED-LOOP MEAL STUDY IN YOUTHS WITH TYPE 1 DIABETES: A MODELING ANALYSIS

Session Name
ARTIFICIAL PANCREAS
Session Type
E-POSTER VIEWING (EXHIBITION HOURS)
Date
20.02.2020, Thursday
Session Time
09:30 - 15:30
Channel
E-Poster Area
Lecture Time
09:52 - 09:53
Presenter
  • Michele Schiavon, Italy
Authors
  • Michele Schiavon, Italy
  • Alfonso Galderisi, United States of America
  • Kristen Kraemer, United States of America
  • Filippo Moret, Italy
  • Eda Cengiz, United States of America
  • Chiara Dalla man, Italy

Abstract

Background and Aims

Intra-individual variability in insulin absorption after subcutaneous (SC) infusion may impair glycemic outcomes and has not been widely studied in the hybrid closed-loop (HCL) setting. Our aim was to ascertain the intra-individual variability in SC insulin absorption by means of a previously validated model (Schiavon et al., IEEE 2018) during a standardized HCL meal study.

Methods

Ten youths with T1D (age=20.9±3.7 y; BMI=23.6±4.5 kg/m2; TDD= 50.6±16.3 U/day) underwent two consecutive, standardized meal studies (70g carbohydrate breakfast and lunch meals) on the same day during DiAs HCL (CGM: Dexcom G4 Platinum with software 505; Insulin pump: Tandem t:slimTM) treatment. Pre-meal insulin bolus was determined based on subjects’ insulin to carbohydrate ratio and was delivered at the beginning of each meal. Plasma insulin aspart concentrations were measured every 10min for 4h during each meal and were used to estimate, for each subject and for each meal, a set of SC insulin absorption parameters (Figure A). The primary metric to assess intra-individual variability of model-derived parameters was the between-meals coefficient of variation (CV %).

Results

As shown in Figure B, mean values of model parameters have been similar between meals (p=NS); however mean intra-individual variability (CV) ranged from 34-94%, with the highest CV for the model parameter representing the direct absorption of non-monomeric insulin to plasma (ka1).

figure_final_rescaled.png

Conclusions

Our preliminary results suggest high intra-individual variability in SC insulin absorption during HCL treatment and underline the importance of optimizing insulin delivery algorithms to account for such variability to improve treatment outcomes.

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