A Randomized Multicenter Trial Comparing the GlucoWatch Biographer With Standard Glucose Monitoring in Children With Type 1 Diabetes

The Diabetes Research in Children Network (DirecNet) Study Group. Diabetes Care. 2005;28:1103-1106.

This study was designed to determine the effectiveness of the GlucoWatch G2 Biographer (GW2B) in children with type 1 diabetes when compared with traditional home glucose monitoring devices. The GW2B, a device which adheres to the skin and extracts interstitial fluid for glucose measurement, was previously studied in a small single-center, 3-month randomized trial. Although the results suggested that GW2B use resulted in reduced A1C and hypoglycemic episodes, a larger, more definitive study was needed.

A total of 200 subjects, ranging from 7 to <18 years of age, participated in this study. Each subject was randomly assigned to either the GW2B group (GlucoWatch coupled with standard glucose monitoring) or the usual care group (standard glucose monitoring only), and reported to 1 of 5 centers for testing. Participants reported glucose data on a weekly basis through a questionnaire, and at 3 and 6 months CGMS sensors were inserted to report glucose levels every 5 minutes for 48 hours. Follow-up visits at 3 and 6 months monitored skin reaction in the GW2B group, and all subjects reported on satisfaction levels at the end of 6 months.

Mean A1C levels did not change significantly from baseline levels of 8.0% over the course of this study. A1C was improved by 0.5% in 28% of the GW2B group versus 21% in the usual care group. However, CGMS sensors did not indicate a significant difference in glycemic control between the two groups. Severe hypoglycemic events occurred in 7 subjects in the GW2B group and 2 subjects in the usual care group, but the number of episodes of symptomatic hypoglycemia reported on the weekly questionnaire was slightly higher in the latter group. Skin irritation from wearing the GW2B was reported by all participants in the GW2B group at least once in the 6 month followup period. The most commonly reported reason for discontinued use of the GW2B was skin irritation, with 48 subjects documented to have moderate reactions.

This study found that use of GW2B in addition to standard glucose monitoring did not result in a significant improvement in glycemic control or a reduction in the frequency of hypoglycemic events when compared with standard glucose monitoring alone. These findings differ greatly from the previous randomized trial of GW2B where A1C levels were decreased more in the GW2B group versus the usual care group. The previous trial also reported more frequent hypoglycemic events in the GW2B study group than the control. Although the GlucoWatch G2 Biographer has the potential to help adolescents with type 1 diabetes manage their glucose levels, further studies will have to be performed to evaluate whether its benefits outweigh its shortcomings.