Unveiling the Spectrum of Glucose Variability: A Novel Perspective on FreeStyle Libre Monitoring Data

Area of Science:

• Endocrinology
• Metabolic Diseases
• Diabetes Management

Background:

• Type 1 diabetes (T1D) is associated with long-term microvascular and macrovascular complications.
• Continuous glucose monitoring (CGM) generates vast data, offering opportunities to study and mitigate diabetes complications.

Purpose of the Study:

• To analyze CGM data to identify patterns in glucose levels, fluctuations, and time-above-threshold.
• To investigate the potential for improving metabolic control by targeting specific times of day.

Main Methods:

• Downloaded CGM data from 89 T1D individuals over 18 months.
• Calculated Glucose Management Index (GMI), Average Glucose Fluctuation (AGF), and % Above Critical Threshold (ACT).
• Analyzed % Average Value Over Time of Day (%AVTD) for GMI, AGF, and ACT.

Main Results:

• A strong correlation (r²=0.82) was found between GMI and HbA1c.
• Elevated %ACT was observed even at lower GMI levels in some patients.
• %AVTD analysis showed increased GMI and ACT in the afternoon/evening, peaking at 22:00.

Conclusions:

• Percentage of glucose results above 18 mmol/l increases exponentially above 54 mmol/mol HbA1c.
• %AVTD is a valuable measure for assessing daily glycemic patterns.
• Metabolic control improvements should focus on afternoon and evening periods due to higher GMI, AGF, and ACT risks.