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. 2024 Jul 29:19322968241262106.
doi: 10.1177/19322968241262106. Online ahead of print.

Differences Between Glycated Hemoglobin and Glucose Management Indicator in Real-Time and Intermittent Scanning Continuous Glucose Monitoring in Adults With Type 1 Diabetes

Jee Hee Yoo  1   2 , Sun Joon Moon  3 , Cheol-Young Park  3 , Jae Hyeon Kim  4
Affiliations

Differences Between Glycated Hemoglobin and Glucose Management Indicator in Real-Time and Intermittent Scanning Continuous Glucose Monitoring in Adults With Type 1 Diabetes

Jee Hee Yoo et al. J Diabetes Sci Technol. .

Abstract

Background: This study demonstrates the difference between glucose management indicator (GMI) and glycated hemoglobin (HbA1c) according to sensor mean glucose and HbA1c status using 2 continuous glucose monitoring (CGM) sensors in people with type 1 diabetes.

Methods: A total of 275 subjects (117 Dexcom G6 [G6] and 158 FreeStyle Libre 1 [FL]) with type 1 diabetes was included. The G6 and FL sensors were used, respectively, over 90 days to analyze 682 and 515 glycemic profiles that coincide with HbA1c.

Results: The mean HbA1c was 6.6% in Dexcom G6 and 7.2% in FL profiles. In G6 profiles, GMI was significantly higher than HbA1c irrespective of mean glucose (all P < .001, mean difference: 0.58% ± 0.49%). The GMI was significantly higher than the given HbA1c when HbA1c was below 8.0% (all P < .001). The discordance was the highest at 0.9% for lower HbA1c values (5.0%-5.9%). The proportion of discordance >0.5% improved from 60.1% to 30.9% when using the revised GMI equation in G6 profiles. In FL profile, the overall mean difference between GMI and HbA1c was 0 (P = .966). The GMI was significantly lower by 0.9% than HbA1c of 9.0% to 9.9% and higher by 0.5% in HbA1c of 5.0% to 5.9% (all P < .001).

Conclusions: The GMI is overestimated in G6 users, particularly those with well-controlled diabetes, but the GMI and HbA1c discordance improved with a revised equation from the observed data. The FL profile showed greater discordance for lower HbA1c levels or higher HbA1c levels.

Keywords: HbA1c; continuous glucose monitoring; glucose management indicator; sensor mean glucose; type 1 diabetes.

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Conflict of interest statement

Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.
Figure 1.
(A) and (D) Linear regression analysis between HbA1c and mean glucose derived from specific sensor types. (B) and (E) Difference between GMI and HbA1c according to mean glucose status. (C) and (F) Difference between GMI and HbA1c according to HbA1c level. The solid blue line is the regression equation from the observed profiles. The broken red line is the original published GMI equation from Bergenstal et al: original GMI (%) = 3.31 + 0.02392 × sensor mean glucose (mg/dL) CGM, continuous glucose monitoring; FL, FreeStyle Libre 1; G6, Dexcom G6; GMI, glucose management indicator; is-CGM, intermittent scanning continuous glucose monitoring; rt-CGM, real-time continuous glucose monitoring.
See this image and copyright information in PMC

References

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