REDWOOD CITY, CALIFORNIA. The GlucoWatch is a device for measuring blood sugar level automatically without the need for drawing blood. It is non-invasive, is worn on the wrist like a watch, and provides readings every 20 minutes. With the trend towards more aggressive treatment of diabetes the GlucoWatch fills the need for the more frequent glucose measurements required to support this approach. Aggressive treatment means more insulin injections, dietary adjustments or taking of oral diabetes drugs throughout the day in order to keep glucose on an even keel. Unfortunately, this approach can create a "yo-yo" effect whereby periods of high glucose levels alternate with low (hypoglycemic) levels.
Researchers at Cygnus Inc., the manufacturer of the GlucoWatch, and the University of California Medical School now report that the GlucoWatch can be used effectively to warn of hypoglycemia. Their study involved over 3,000- paired GlucoWatch and blood glucose readings. The researchers found that the GlucoWatch would "catch" 24 per cent of all hypoglycemic events (blood glucose at or below 3.9 mmol/L [70 mg/dL]) with an accuracy of 99 per cent. In other words, the sensitivity was 24 per cent and the specificity 99 per cent. Setting the alarm to 5.6 mmol/L (100 mg/dL), on the other hand, produced a sensitivity of 75 per cent and a specificity of 10 per cent. Although these results are still not optimal they are significantly better than what could be obtained by standard blood sample testing even four times per day. NOTE: This study was partially funded by Cygnus Inc., the manufacturer of the GlucoWatch.
Pitzer, Kenneth R., et al. Detection of hypoglycemia with the GlucoWatch biographer. Diabetes Care, Vol. 24, May 2001, pp. 881-85
Reach, Gerard. Which threshold to detect hypoglycemia? Diabetes Care, Vol. 24, May 2001, pp. 803-04 (editorial)