Glucose Management Indicator for People with Type 1 Asian Diabetes Is Different from That of the Published Equation: Differences by Glycated Hemoglobin Distribution.

Background: We aimed to determine whether there are racial differences in glucose management indicator (GMI) equation for Asians and propose an adjusted GMI equation specific to Asians. Methods: This was a 24-week, prospective, observational study. A total of 106 Korean subjects with type 1 diabetes was included in the analyses. Continuous glucose monitoring (CGM: Dexcom G5) data and glycated hemoglobin (HbA1c) were obtained at the end of 3 months (n = 106) and 6 months (n = 70) of use of a CGM device. Full 3-month CGM data were collected from 176 patients. Results: Linear regression analysis between HbA1c and CGM-derived mean glucose (GMI [%] = 2.814 + 0.026 × mean glucose [mg/dL], R2 = 0.739, P < 0.001) showed significant correlation. An increase corresponding to each 25 mg/dL increase of mean glucose was higher with the Asian-Dexcom-specific GMI (0.7%) than with the published GMI (0.6%). The mean Asian-Dexcom-specific GMI was significantly lower than the published GMI (P = 0.022), especially in patients with HbA1c <7.0% (<6.0%: P = 0.003, 6.0%-6.9%: P = 0.001). Conclusions: The GMI equation specific for Asian Type 1 diabetes was different from the published GMI equation. For a given CGM-derived mean glucose, GMI calculated with the published equation could overestimate HbA1c in Asian subjects with HbA1c <7.0%. Although race partially explains the differences in GMI equation between published and Asian data, future research with larger databases is needed to develop a specific formula for Asian populations.