In a European multicenter, randomized controlled trial of 154 patients with type 1 diabetes, the group that wore the continuous monitor throughout the trial achieved a substantial decrease in A1C of 1.1 points compared with a 0.4-point reduction for the placebo group. A third group that wore the device intermittently saw a decline in A1C of 0.7 points.

Further, patients in the continuous-monitoring group had meaningful decreases in excursions in glucose below 70 and over 190, yielding significantly less glycemic instability and fewer "swings." Such variability sometimes results in unexpected, costly visits to the emergency room to treat severe hypoglycemia and diabetic ketoacidosis. In particular, results showed that both the number of hypoglycemic events as well as the duration of events were significantly reduced.

The Guardian RT, the glucose monitoring device tested in the study, was approved by the U.S. Food and Drug Administration in July and by the European Union earlier this year. The device includes a small sensor that can be self-inserted under the skin, and a discrete monitor that records and displays glucose levels every five minutes. It is expected to enable patients to view glucose trends throughout the day and night, and to determine how diet, exercise, and medication affect glucose levels. A limited launch in a small number of U.S. cities this fall is planned for the device, which is indicated for use in patients with type 1 and type 2 diabetes who are 18 years and older and need improved glucose control.

The major advantage of this technology, he commented, was that patients could make changes to therapy much earlier, with preventive actions — up until now, this has been impossible. When asked whether there was a concern that patients might have too much data or might "over-correct," Dr. Bolinder said that there was an initial concern by some that this might be true, but the study showed that the opposite was the case, that hypoglycemia and hyperglycemia were reduced as a result of the trial.