title: Blood glucose prediction using stochastic modeling in neonatal intensive care.
abstract: Hyperglycemia is a common metabolic problem in premature, low-birth-weight infants. Blood glucose homeostasis in this group is often disturbed by immaturity of endogenous regulatory systems and the stress of their condition in intensive care. A dynamic model capturing the fundamental dynamics of the glucose regulatory system provides a measure of insulin sensitivity (S(I)). Forecasting the most probable future S(I) can significantly enhance real-time glucose control by providing a clinically validated/proven level of confidence on the outcome of an intervention, and thus, increased safety against hypoglycemia. A 2-D kernel model of S(I) is fitted to 3567 h of identified, time-varying S(I) from retrospective clinical data of 25 neonatal patients with birth gestational age 23 to 28.9 weeks. Conditional probability estimates are used to determine S(I) probability intervals. A lag-2 stochastic model and adjustments of the variance estimator are used to explore the bias-variance tradeoff in the hour-to-hour variation of S(I). The model captured 62.6% and 93.4% of in-sample S(I) predictions within the (25th-75th) and (5th-95th) probability forecast intervals. This overconservative result is also present on the cross-validation cohorts and in the lag-2 model. Adjustments to the variance estimator found a reduction to 10%-50% of the original value provided optimal coverage with 54.7% and 90.9% in the (25th-75th) and (5th-95th) intervals. A stochastic model of S(I) provided conservative forecasts, which can add a layer of safety to real-time control. Adjusting the variance estimator provides a more accurate, cohort-specific stochastic model of S(I) dynamics in the neonate.
authors.affiliation: Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand. ajc190@student.canterbury.ac.nz
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Le Compte
authors.forename: Dominic S
authors.initials: DS
authors.lastname: Lee
authors.forename: J Geoffrey
authors.initials: JG
authors.lastname: Chase
authors.forename: Jessica
authors.initials: J
authors.lastname: Lin
authors.forename: Adrienne
authors.initials: A
authors.lastname: Lynn
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Shaw
mesh_terms: D000465:Algorithms; D001786:Blood Glucose / Q000032:analysis*; D015331:Cohort Studies; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D007234:Infant, Premature / Q000097:blood*; D019102:Infant, Very Low Birth Weight / Q000097:blood*; D015931:Intensive Care, Neonatal; D008954:Models, Biological; D011237:Predictive Value of Tests; D013269:Stochastic Processes
chemical_list: D001786:Blood Glucose