Tsalikian Eva, Kollman Craig, Mauras Nelly, Weinzimer Stuart, Buckingham Bruce, Xing Dongyuan, Beck Roy, Ruedy Katrina, Tamborlane William, Fiallo-Scharer Rosanna
DirecNet Coordinating Center, Jaeb Center for Health Research, Tampa, FL 33647, USA.
Diabetes Technol Ther. 2004 Oct;6(5):559-66. doi: 10.1089/dia.2004.6.559.
The GlucoWatch G2 Biographer (GW2B) (Cygnus, Inc., Redwood City, CA) provides near-continuous monitoring of glucose values in near real time. This device is equipped with two types of alarms to detect hypoglycemia. The hypoglycemia alarm is triggered when the current glucose measurement falls below the level set by the user. The "down alert" alarm is triggered when extrapolation of the current glucose trend anticipates hypoglycemia to occur within the next 20 min.
We used data from an inpatient accuracy study to assess the performance of these alarms. During a 24-h clinical research center stay, 89 children and adolescents with Type 1 diabetes mellitus (3.5-17.7 years old) wore 174 GW2B devices and had frequent serum glucose determinations during the day and night.
Sensitivity to detect hypoglycemia (reference glucose < or = 60 mg/dL) during an insulin-induced hypoglycemia test was 24% with the hypoglycemia alarm alone and 88% when combined with the down alert alarm. Overnight sensitivity from 11 p.m. to 6 a.m. was 23% with the hypoglycemia alarm alone and 77% when combined with the down alert alarm. For 16% of hypoglycemia alarms, the reference glucose was above 70 mg/dL for 30 min before and after the time of the alarm. For the two alarm types combined, the corresponding false-positive rate increased to 62%.
The down alert alarm substantially improves the sensitivity of the GW2B to detect hypoglycemia at the price of a large increase in the false alarm rate. The utility of these alarms in the day-to-day management of children with diabetes remains to be determined.
GlucoWatch G2生物记录仪（GW2B）（Cygnus公司，加利福尼亚州红木城）可近乎实时地对血糖值进行近乎连续的监测。该设备配备了两种用于检测低血糖的警报。当当前血糖测量值低于用户设定的水平时，低血糖警报被触发。当根据当前血糖趋势推断预计在接下来20分钟内会发生低血糖时，“下降警报”被触发。
我们使用了一项住院患者准确性研究的数据来评估这些警报的性能。在临床研究中心停留的24小时期间，89名1型糖尿病儿童和青少年（3.5 - 17.7岁）佩戴了174台GW2B设备，并在白天和晚上频繁进行血清葡萄糖测定。
在胰岛素诱导的低血糖测试期间，仅使用低血糖警报时检测低血糖（参考血糖≤60 mg/dL）的灵敏度为24%，与下降警报联合使用时为88%。从晚上11点到早上6点的夜间灵敏度，仅使用低血糖警报时为23%，与下降警报联合使用时为77%。对于16%的低血糖警报，在警报时间前后30分钟，参考血糖高于70 mg/dL。对于两种警报类型联合使用的情况，相应的假阳性率增加到62%。
下降警报以大幅增加误报率为代价，显著提高了GW2B检测低血糖的灵敏度。这些警报在糖尿病儿童日常管理中的效用仍有待确定。
