Design, development, and evaluation of a novel microneedle array-based continuous glucose monitor.

The development of accurate, minimally invasive continuous glucose monitoring (CGM) devices has been the subject of much work by several groups, as it is believed that a less invasive and more user-friendly device will result in greater adoption of CGM by persons with insulin-dependent diabetes. This article presents the results of preliminary clinical studies in subjects with diabetes of a novel prototype microneedle-based continuous glucose monitor. In this device, an array of tiny hollow microneedles is applied into the epidermis from where glucose in interstitial fluid (ISF) is transported via passive diffusion to an amperometric glucose sensor external to the body. Comparison of 1396 paired device glucose measurements and fingerstick blood glucose readings for up to 72-hour wear in 10 diabetic subjects shows the device to be accurate and well tolerated by the subjects. Overall mean absolute relative difference (MARD) is 15% with 98.4% of paired points in the A+B region of the Clarke error grid. The prototype device has demonstrated clinically accurate glucose readings over 72 hours, the first time a microneedle-based device has achieved such performance.

Use of the GlucoWatch biographer in children with type 1 diabetes.

OBJECTIVE: To determine whether use of the GlucoWatch biographer improves glucose control in children and adolescents with type 1 diabetes. METHODS: Forty children in poor glucose control (glycohemoglobin [HbA1c] >8%) were randomized to diabetes management with or without glucose monitoring using the biographer. Conventional glucose monitoring was performed 4 times daily in both groups. Those randomized to the biographer group were asked to wear the device 4 times per week for 3 months (intervention phase) and to perform blood glucose monitoring if the biographer alerted them that glucose was < or =70 mg/dL (3.9 mmol/L) or > or =300 mg/dL (16.7 mmol/L). After 3 months, all patients received biographers and were followed for 6 months (observation phase). HbA1c values were determined at baseline and after 1, 3, 6, and 9 months. RESULTS: The median HbA1c was 8.6% and 8.9% (control versus biographer) at baseline and was significantly lower in the biographer group after 3 months (8.4% vs 9%). More hypoglycemia was detected when subjects were wearing the biographer, especially at night. No severe hypoglycemia occurred. During the observation phase, HbA1c values at 6 months were 8.5% and 8.3% and at 9 months were 8.6% and 8.4% in the control and biographer groups, respectively. Two children dropped out of the study, 1 because of skin irritation from using the device. CONCLUSIONS: The GlucoWatch biographer was well tolerated by children and adolescents and significantly improved glucose control compared with standard therapy. The use of the biographer with an alarm to detect nocturnal hypoglycemia has the potential to increase the safety of diabetes management in children.