Diabetes Metab J.  2024 May;48(3):429-439. 10.4093/dmj.2023.0083.

Optimal Coefficient of Variance Threshold to Minimize Hypoglycemia Risk in Individuals with Well-Controlled Type 1 Diabetes Mellitus

• Yoo JH
• Yang SH
• Jin SM
• Kim JH

• KMID: 2555774
• DOI: http://doi.org/10.4093/dmj.2023.0083

Abstract

Background
This study investigated the optimal coefficient of variance (%CV) for preventing hypoglycemia based on real-time continuous glucose monitoring (rt-CGM) data in people with type 1 diabetes mellitus (T1DM) already achieving their mean glucose (MG) target.
Methods
Data from 172 subjects who underwent rt-CGM for at least 90 days and for whom 439 90-day glycemic profiles were available were analyzed. Receiver operator characteristic analysis was conducted to determine the cut-off value of %CV to achieve time below range (%TBR)^{<54 mg/dL} <1 and =0.
Results
Overall mean glycosylated hemoglobin was 6.8% and median %TBR^{<54 mg/dL} was 0.2%. MG was significantly higher and %CV significantly lower in profiles achieving %TBR^{<54 mg/dL} <1 compared to %TBR^{<54 mg/dL} ≥1 (all P<0.001). The cut-off value of %CV for achieving %TBR^{<54 mg/dL} <1 was 37.5%, 37.3%, and 31.0%, in the whole population, MG >135 mg/dL, and ≤135 mg/dL, respectively. The cut-off value for %TBR^{<54 mg/dL}=0% was 29.2% in MG ≤135 mg/dL. In profiles with MG ≤135 mg/dL, 94.2% of profiles with a %CV <31 achieved the target of %TBR^{<54 mg/dL} <1, and 97.3% with a %CV <29.2 achieved the target of %TBR<54 mg/ dL=0%. When MG was >135 mg/dL, 99.4% of profiles with a %CV <37.3 achieved %TBR^{<54 mg/dL} <1.
Conclusion
In well-controlled T1DM with MG ≤135 mg/dL, we suggest a %CV <31% to achieve the %TBR^{<54 mg/dL} <1 target. Furthermore, we suggest a %CV <29.2% to achieve the target of %TBR^{<54 mg/dL} =0 for people at high risk of hypoglycemia.

Keyword

Blood glucose; Blood glucose self-monitoring; Diabetes mellitus, type 1; Hypoglycemia

Figure

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  Fig. 1. Cut-off value of coefficient of variance (%CV) to achieve time below range (%TBR)<54 mg/dL < 1 using receiver operator characteristic analysis. (A) Whole population, (B) mean glucose >135 mg/dL (glucose management indicator [GMI] >6.5%), (C) mean glucose ≤135 mg/dL (GMI ≤6.5%) and scatter plot of %CV according to the presence of %TBR<54 mg/dL ≥1. (D) Whole population, (E) mean glucose >135 mg/dL (GMI >6.5%), (F) mean glucose ≤135 mg/dL (GMI ≤6.5%). AUC, area under the curve; CI, confidence interval.

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  Fig. 2. (A) Percentage of profiles achieving time below range (%TBR)<54 mg/dL <1, (B) the value of %TBR<54 mg/dL according to a coefficient of variance (%CV) of 31% in profiles with mean glucose ≤135 mg/dL (glucose management indicator [GMI] ≤6.5%), (C) percentages of profiles achieving %TBR<54 mg/dL <1, and (D) the value of %TBR<54 mg/dL for a %CV of 37.3% in profiles with mean glucose >135 mg/dL (GMI >6.5%). IQR, interquartile range.

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  Fig. 3. (A) Cut-off value of coefficient of variance (%CV) to achieve time below range (%TBR)<54 mg/dL=0 using receiver operator characteristic analysis and (B) scatter plot of %CV according to the presence of %TBR<54 mg/dL in profiles with a mean glucose ≤135 mg/dL, and (C) percentage of profiles achieving %TBR<54 mg/dL=0. GMI, glucose management indicator; AUC, area under the curve; CI, confidence interval.

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