Rates of Glucose Change Measured by Blood Glucose Meter and the GlucoWatch Biographer During Day, Night, and Around Mealtimes

Rates of Glucose Change Measured by Blood Glucose Meter and the GlucoWatch Biographer During Day, Night, and Around Mealtimes Timothy C. Dunn , BS , Richard C. Eastman , MD and Janet A. Tamada , PHD From Cygnus, Redwood City, California Address correspondence and reprint requests to Richard C. Eastman, MD, Cygnus, 400 Penobscot Dr., Redwood City, CA 94063. E-mail: reastman{at}cygn.com Abstract OBJECTIVE —The purpose of this study was to characterize the distribution of the rate of change of blood glucose for a diabetic population. RESEARCH DESIGN AND METHODS —The study population consisted of 124 adults with type 1 or type 2 diabetes requiring insulin. Study participants applied a GlucoWatch Biographer during the day at home for 5 consecutive days and took finger-prick blood glucose measurements hourly. Subjects kept a diary of meals. The Biographer frequently and automatically measured glucose up to three times per hour for up 12 h. Rates of glucose change were calculated for both Biographer and blood glucose measurements. Rates of glucose change during a separate study of 134 subjects were determined for daytime and nighttime use. RESULTS —Mean (±SD) rates of change of glucose of −0.36 ± 0.95 and 0.36 ± 0.99 mg · dl −1 · min −1 were found before and after lunch using blood glucose data and −0.31 ± 1.23 and 0.43 ± 1.26 using Biographer data. For both types of diabetes, rates of glucose change exceeded 2 mg · dl −1 · min −1 before and after meals ∼10% of the time. Periprandial glucose patterns showed some significant differences between type 1 and type 2 diabetic subjects. Glucose levels changed more gradually at night than during the day. CONCLUSIONS —Glucose values were almost equally unstable before and after meals. Glycemic instability around dinner was different in type 1 and type 2 diabetes. The GlucoWatch Biographer was found to be effective in tracking trends in glucose levels and yielded similar results as obtained by finger-prick blood samples. Footnotes A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances. Accepted May 13, 2004. Received February 2, 2004. DIABETES CARE