title: Real-time hypoglycemia detection from continuous glucose monitoring data of subjects with type 1 diabetes.
abstract: BACKGROUND
  Hypoglycemia is a potentially fatal condition. Continuous glucose monitoring (CGM) has the potential to detect hypoglycemia in real time and thereby reduce time in hypoglycemia and avoid any further decline in blood glucose level. However, CGM is inaccurate and shows a substantial number of cases in which the hypoglycemic event is not detected by the CGM. The aim of this study was to develop a pattern classification model to optimize real-time hypoglycemia detection.
  
  
  METHODS
  Features such as time since last insulin injection and linear regression, kurtosis, and skewness of the CGM signal in different time intervals were extracted from data of 10 male subjects experiencing 17 insulin-induced hypoglycemic events in an experimental setting. Nondiscriminative features were eliminated with SEPCOR and forward selection. The feature combinations were used in a Support Vector Machine model and the performance assessed by sample-based sensitivity and specificity and event-based sensitivity and number of false-positives.
  
  
  RESULTS
  The best model was composed by using seven features and was able to detect 17 of 17 hypoglycemic events with one false-positive compared with 12 of 17 hypoglycemic events with zero false-positives for the CGM alone. Lead-time was 14 min and 0 min for the model and the CGM alone, respectively.
  
  
  CONCLUSIONS
  This optimized real-time hypoglycemia detection provides a unique approach for the diabetes patient to reduce time in hypoglycemia and learn about patterns in glucose excursions. Although these results are promising, the model needs to be validated on CGM data from patients with spontaneous hypoglycemic events.
authors: Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, Aalborg, Denmark. mhj@hst.aau.dk
authors: Morten Hasselstrøm
authors: MH
authors: Jensen
authors: Toke Folke
authors: TF
authors: Christensen
authors: Lise
authors: L
authors: Tarnow
authors: Edmund
authors: E
authors: Seto
authors: Mette
authors: M
authors: Dencker Johansen
authors: Ole Kristian
authors: OK
authors: Hejlesen
mesh_terms: D000328:Adult; D000465:Algorithms; D003627:Data Interpretation, Statistical; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy / Q000378:metabolism*; D045604:Extracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D005189:False Positive Reactions; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007003:Hypoglycemia / Q000139:chemically induced / Q000175:diagnosis* / Q000517:prevention & control; D007004:Hypoglycemic Agents / Q000009:adverse effects / Q000627:therapeutic use; D061267:Insulin Aspart / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D018670:Monitoring, Ambulatory; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D007004:Hypoglycemic Agents; D061267:Insulin Aspart; D005947:Glucose