title: Characterisation of linear predictability and non-stationarity of subcutaneous glucose profiles.
abstract: Continuous glucose monitoring is increasingly used in the management of diabetes. Subcutaneous glucose profiles are characterised by a strong non-stationarity, which limits the application of correlation-spectral analysis. We derived an index of linear predictability by calculating the autocorrelation function of time series increments and applied detrended fluctuation analysis to assess the non-stationarity of the profiles. Time series from volunteers with both type 1 and type 2 diabetes and from control subjects were analysed. The results suggest that in control subjects, blood glucose variation is relatively uncorrelated, and this variation could be modelled as a random walk with no retention of 'memory' of previous values. In diabetes, variation is both greater and smoother, with retention of inter-dependence between neighbouring values. Essential components for adequate longer term prediction were identified via a decomposition of time series into a slow trend and responses to external stimuli. Implications for diabetes management are discussed.
authors.affiliation: School of Engineering, University of Warwick, Coventry CV4 7AL, UK. n.khovanova@warwick.ac.uk
authors.forename: N A
authors.initials: NA
authors.lastname: Khovanova
authors.forename: I A
authors.initials: IA
authors.lastname: Khovanov
authors.forename: L
authors.initials: L
authors.lastname: Sbano
authors.forename: F
authors.initials: F
authors.lastname: Griffiths
authors.forename: T A
authors.initials: TA
authors.lastname: Holt
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D008991:Monitoring, Physiologic / Q000706:statistics & numerical data*; D013269:Stochastic Processes; D040521:Subcutaneous Tissue / Q000378:metabolism*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D005947:Glucose