Continuous Glucose Monitoring Sensor Glucose Data Analysis of Time in Range, Time Above Range, Time Below Range and Waveform Comparison Study of Time in Range Curve Against both Average Daily Glucose Curve and Glucose Fluctuation Curve for a 3.3 Year Period based on GH-Method: Math Physical Medicine (No. 500)

Abstract

Gerald C Hsu

The author applies quantitative pattern and trend analysis tools using his collected continuous glucose monitoring (CGM) sensor data during a 3.3 year period from 5/8/2018 to 8/25/2021. Special attention has been placed on applying the American Diabetes Association (ADA) 2020 Guidelines for Time In Range (TIR) % with TIR average glucose values, Time Above Range (TAR) % with TAR average glucose value, and Time Below Range (TBR) % with TBR average glucose value. The purpose of this article is to study the correlations between the TIR curve and both average daily glucose curve (eAG) and glucose fluctuation curve (GF). GF is defined as the difference between the maximum glucose and the minimum glucose within one day or 24 hours duration. This GF term expresses the same meaning as the glycemic variability (GV) used by some diabetes research scientists. However, the author prefers GF over GV since GF describes the amplitude of glucose excursion in an exact and most direct way. Depending on the object of his research project, he sometimes selects the GF value within a meal’s PPG waveform of a 3-hours duration. Furthermore, the “primary range” of TIR is defined between 70 mg/dL and 180 mg/dL while a “secondary range” of TIR is defined between 70 mg/dL and 140 mg/dL. Of course, both the TIR’s and TAR’s percentages and their averaged values of secondary range (difference of 70 mg/dL) are smaller than the primary range results due to the secondary range’s narrower glucose range of 40 mg/dL (110-70 or 180-140). In summary, there are five noticeable findings from this study: (1) TIR: His TIR percentage (89%) and average TIR value (121 mg/dL) of the primary range, along with the TIR percentage (72%) and average TBR value (114 mg/dL) of the secondary range represent the majority of the data. This means that his type 2 diabetes (T2D) is quite well under control. (2) TBR: His TBR percentage (5%) and average TBR value (65 mg/dL) of the primary range, along with the same TBR percentage (5%) and the same average TBR value (65 mg/dL) of the secondary range contain rather small amounts. This means that his risk of having hypoglycemia (insulin shock) is relatively low. (3) TAR: His TAR percentage (6%) and average TAR value (194 mg/dL) of the primary range have a lower percentage but a higher averaged glucose value than the TAR percentage (23%) and average TBR value (158 mg/dL) of the secondary range. However, the higher TAR percentage (23%) and its associated lower averaged TBR value (158 mg/dL) of the secondary range show that his T2D’s hyperglycemia control still has room (specifically between 140 mg/dL and 180 mg/dL) for improvement. (4) T2D: The existence with occasional glucose levels of being greater than 180 mg/dL or below 70 mg/dL confirms that hestill is a “T2D patient” regardless of his diabetes conditions being well under controlled since 2017. (5) Correlation coefficients: First of all, his eAG and GF have a strong correlation of +69%. This means that when his eAG is high, then most likely GF is also high. Secondly, his eAG and TIR have a correlation of -79% (negatively high) and GF and TIR have an even stronger correlation of -89% (negatively higher). These two results of very high negative correlations indicate that when both eAG and GF are higher, his TIR would be lower, and vice versa.

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