Y. Ruan (1,2) Malgorzata E. Wilinska (1,2) Hood Thabit (2) R. Hovorka (1,2)
(1) Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom, (2) Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom
Objectives: Parameters of physiological models of glucose-insulin regulation in type 1 diabetes have been estimated using data collected over a relatively short period of time and lack the description of day-to-day variability. We developed a new hierarchical model to relate subcutaneous insulin delivery and carbohydrate intake to continuous glucose monitoring over 12 weeks.
Methods: Sensor glucose data (sampled every 10 min), insulin aspart delivery and meal intake were analysed from 32 adults with type 1 diabetes (male/female 4/2, age 40.8±2.6 years, BMI 25.3±3.6 kg/m2, HbA1C 8.2±1.0 %) who underwent a 12-week home study of closed-loop insulin delivery [1]. A compartment model comprised five linear differential equations with a closed-form solution. Model parameters were estimated using the Markov chain Monte Carlo approach within a hierarchical Bayesian model framework.
Results: Physiologically plausible a posteriori distributions of model parameters including insulin sensitivity, time-to-peak insulin action, time-to-peak gut absorption, and carbohydrate bioavailability, and good model fit were observed. Day-to-day variability of model parameters was estimated in the range 38 to 79% for insulin sensitivity and 35 to 48% time-to-peak insulin action.
Conclusions: A linear Bayesian hierarchical approach is feasible to model 12-week glucose-insulin relationship using conventionally measured data.
References:
[1] Thabit H, Tauschmann M, Allen JM, Leelarathna L, Hartnell S, Wilinska ME, Acerini CL, Dellweg S, Benesch C, Heinemann L, Mader JK, Holzer M, Kojzar H, Exall J, Yong J, Pichierri J, Barnard KD, Kollman C, Cheng P, Hindmarsh PC, Campbell FM, Arnolds S, Pieber TR, Evans ML, Dunger DB, Hovorka R, Consortium AP, Consortium APh: Home use of an artificial beta cell in type 1 diabetes. N Engl J Med 2015;373:2129-2140
Reference: PAGE 25 (2016) Abstr 3689 [www.page-meeting.org/?abstract=3689]
Poster: Methodology - New Modelling Approaches