Detection of hypoglycemia with the GlucoWatch biographer

OBJECTIVE - Hypoglycemia is a common acute complication of diabetes therapy . The GlucoWatch biographer provides frequent and automatic glucose measure ments with an adjustable low-glucose alarm. We have analyzed the performanc e of the biographer low-glucose alarm relative to hypoglycemia as defined b y blood glucose less than or equal to3.9 mmol/l. RESEARCH DESIGN AND METHODS - The analysis was based on 1,091 biographer us es from four clinical trials, which generated 14,487 paired (biographer and blood glucose) readings. RESULTS - The results show that as the low-glucose alert level of the biogr apher is increased. the number of rme positive alerts (alarm sounds and blo od glucose less than or equal to3.9 mmol/l) and false positive alerts (alar m sounds but blood glucose >3.9 mmol/l) increased. When analyzed as a funct ion of varying low-glucose alert levels, the results show receiver operator characteristic curves consistent with a highly useful diagnostic tool. Set ting the alert level from 1.1 to 1.7 mmol/l above the level of concern is l ikely to optimize the trade-off between true positives and false positives for each user. When the same blood glucose data are analyzed for typical mo nitoring practices (two or lour measurements per day), the results show tha t fewer hypoglycemic events are detected than those detected with the biogr apher. CONCLUSIONS - The frequent and automatic nature of the biographer readings allows more effective detection of hypoglycemia than that achieved with cur rent medical practice.