Assessment of the Glucose Management Indicator Using Different Sampling Durations
Ryan Bailey, Peter Calhoun, Richard M. Bergenstal, Roy W. Beck
Abstract
We compared the glucose management indicator (GMI) calculated using 14 days of continuous glucose monitor (CGM) data with GMI calculated using <14 days. Analysis included 581 individuals with type 1 diabetes or type 2 diabetes from five clinical trials. The correlation between the 14- and 7-day GMI was 0.95 and the correlation between 14 days versus 10, 5, and 3 days GMI was 0.98, 0.91, and 0.86, respectively. The percentages of GMI values within 0.3% of the 14-day GMI were 98% with 10-day GMI, 87% with 7-day GMI, 77% with 5-day GMI, and 60% with 3-day GMI. Minimal differences were observed between GMI computed using 14 days of data compared with GMI computed with 7 days. Although 10-14 days of CGM data are preferred for computing GMI, for most patients a satisfactory estimate of HbA1c can be obtained with 7 days of data.