title: Methods of evaluating the utility of continuous glucose monitor alerts.
abstract: BACKGROUND
  The evaluation of continuous glucose monitor (CGM) alert performance should reflect patient use in real time. By evaluating alerts as real-time events, their ability to both detect and predict low and high blood glucose (BG) events can be examined.
  
  
  METHODS
  True alerts (TA) were defined as a CGM alert occurring within +/- 30 minutes from the beginning of a low or a high BG event. The TA time to detection was calculated as [time of CGM alert] - [beginning of event]. False alerts (FA) were defined as a BG event outside of the alert zone within +/- 30 minutes from a CGM alert. Analysis was performed comparing DexCom SEVEN PLUS CGM data to BG measured with a laboratory analyzer.
  
  
  RESULTS
  Of 49 low glucose events (BG < or =70 mg/dl), with the CGM alert set to 90 mg/dl, the TA rate was 91.8%. For 50% of TAs, the CGM alert preceded the event by at least 21 minutes. The FA rate was 25.0%. Similar results were found for high alerts.
  
  
  CONCLUSIONS
  Continuous glucose monitor alerts are capable of both detecting and predicting low and high BG events. The setting of alerts entails a trade-off between predictive ability and FA rate. Realistic analysis of this trade-off will guide patients in the effective utilization of CGM.
authors.affiliation: DexCom Inc., San Diego, California, USA.
authors.forename: Apurv
authors.initials: A
authors.lastname: Kamath
authors.forename: Aarthi
authors.initials: A
authors.lastname: Mahalingam
authors.forename: James
authors.initials: J
authors.lastname: Brauker
mesh_terms: D000328:Adult; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D001786:Blood Glucose / Q000032:analysis; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation* / Q000379:methods; D056902:Clinical Alarms / Q000592:standards*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D003951:Diagnostic Errors; D004868:Equipment Failure; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000175:diagnosis; D007332:Insulin Infusion Systems; D008297:Male; D018447:Medical Futility; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods; D012680:Sensitivity and Specificity
chemical_list: D001786:Blood Glucose