Methods of evaluating the utility of continuous glucose monitor alerts.
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.
Kamath
Apurv
A
DexCom Inc., San Diego, California, USA.
Mahalingam
Aarthi
A
Brauker
James
J
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
D001786:Blood Glucose