Changes in Glycemic Risk Index (GRI) and its Association with other Continuous Glucose Monitoring (CGM) Metrics after Automated Insulin Delivery System Initiation in Adults with Type 1 Diabetes

Halis Akturk; Kagan Karakus; David Klonoff; Viral Shah

doi:10.1530/endoabs.90.P344

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Endocrine Abstracts (2023) 90 P344 | DOI: 10.1530/endoabs.90.P344

ECE2023 Poster Presentations Diabetes, Obesity, Metabolism and Nutrition (159 abstracts)

Changes in Glycemic Risk Index (GRI) and its Association with other Continuous Glucose Monitoring (CGM) Metrics after Automated Insulin Delivery System Initiation in Adults with Type 1 Diabetes

Halis Akturk ¹ , Kagan Karakus ² , David Klonoff ^3,4 & Viral Shah ¹

Err

Author affiliations

¹Barbara Davis Center, Aurora, United States; ²Koc University, Istanbul, Turkey; ³Diabetes Technology Society, San Francisco, United States; ⁴Diabetes Research Institute, San Francisco, United States

Objective: To evaluate the GRI and its association with other CGM metrics after initiation of automated insulin delivery (AID) system in adults with type 1 diabetes (awT1D).

Methods: Up to 90 days of CGM data before and after initiation of an AID system from 185 awT1D were collected. GRI with hypoglycemia and hyperglycemia components and other CGM metrics were calculated using cgmanalysis R software and analyzed for 24-hour, nighttime, and daytime. GRI values were assigned to 5 GRI zones as zone A (0-20), zone B (21-40), zone C (41-60), zone D (61-80), zone E (81-100).

Results: After AID initiation, GRI, its two components and other CGM metrics improved significantly (Table-1). The percentage of people in each zone changed as follows: A: 10.8% to 24.7%; B: 23.8% to 58.4%; C: 36.2% to 15.1%, D: 20.5% to 0.5%, and E: 8.7% to 0%. GRI was correlated with time between 181-250 mg/dl before (r=0.691, P<0.001) and after (r=0.818, P<0.001) and time above 250 mg/dl before (r=0.925, P<0.001) and after (r=0.920, P<0.001). GRI was not correlated with time between 54-70 mg/dl before (r=-0.029, P=0.698) and after (r=0.038, P=0.611), and with time below 54 mg/dl before (r=0.123, P=0.096) and after (r=0.140, P=0.058). Improvement in nighttime, compared to daytime, was superior; as seen in increased TIR and decreased GRI (P<0.001 for both). GRI improved by 19.7 percentiles and TIR improved by 14.6 percent.

Table 1 Comparison of CGM metrics before and after AID initiation, n=185
	Before AID Initiation	After AID Initiation	P value
CGM wear time,%	81.25±16.9	88.44±12.71	<0.001
CGM data, days	76.39±18.8	81.11±16.47	0.002
Mean sensor glucose, mg/dl	167.57±29.23	150.32±18.36	<0.001
Glucose management indicator(GMI),%	7.3±0.7	6.90±0.44	<0.001
SD	59.40±13.17	49.16±10.12	<0.001
CV,%	35±5	33±4	<0.001
Time below range, <70 mg/dl(TBR),%	3.23±3.33	1.97±1.98	<0.001
Time between 54-70 mg/dl(TBR2),%	0.65±1.03	0.36±0.5	<0.001
Time below 54 mg/dl(TBR1),%	2.58±2.39	1.62±1.52	<0.001
Time in range, 70-180 mg/dl(TIR),%	58.95±17.29	73.56±11.66	<0.001
Time above range, >180 mg/dl(TAR),%	37.81±18.29	24.47±12.18	<0.001
Time between 181-250 mg/dl,(TAR1),%	24.99±8.92	18.87±7.75	<0.001
Time above 250 mg/dl(TAR2),%	12.83±11.26	5.60±5.15	<0.001
GRI	48.66±21.81	29.01±13.01	<0.001
GRI-Hypoglycemia component	2.72±2.85	1.65±1.68	<0.001
GRI-Hyperglycemia component	25.32±14.52	15.03±8.52	<0.001

Conclusion: GRI was highly correlated with various CGM metrics above (but not below) target range, both before and after AID initiation. Improvement in GRI was greater than improvement in TIR, and both were significant, GRI, compared to TIR, was a better indicator for improved glycemia after AID initiation.