Dysglycemia in adults at risk for or living with non-insulin treated type 2 diabetes: Insights from continuous glucose monitoring

Abstract

Background: Continuous glucose monitoring (CGM) has demonstrable benefits for people living with diabetes, but the supporting evidence is almost exclusively from White individuals with type 1 diabetes. Here, we have quantified CGM profiles in Hispanic/Latino adults with or at-risk of non-insulin treated type 2 diabetes (T2D).

Methods: 100 participants (79 female, 86% Hispanic/Latino [predominantly Mexican], age 54·6 [±12·0] years) stratified into (i) at risk of T2D, (ii) with pre-diabetes (pre-T2D), and (iii) with non-insulin treated T2D, wore blinded CGMs for 2 weeks. Beyond standardized CGM measures (average glucose, glucose variability, time in 70-140 mg/dL and 70-180 mg/dL ranges), we also examined additional CGM measures based on the time of day.

Findings: Standardized CGM measures were significantly different for participants with T2D compared to at-risk and pre-T2D participants (p<0·0001). In addition, pre-T2D participants spent more time between 140 and 180 mg/dL during the day than at-risk participants (p<0·01). T2D participants spent more time between 140 and 180 mg/dL both during the day and overnight compared to at-risk and pre-T2D participants (both p<0·0001). Time in 70-140 mg/dL range during the day was significantly correlated with HbA_1c (r=-0·72, p<0·0001), after adjusting for age, sex, BMI, and waist circumference (p<0·0001).

Interpretation: Standardized CGM measures show a progression of dysglycemia from at-risk of T2D, to pre-T2D, and to T2D. Stratifying CGM readings by time of day and the range 140-180 mg/dL provides additional metrics to differentiate between the groups.

Funding: US Department of Agriculture (Grant #2018-33800-28404) and NSF PATHS-UP ERC (Award #1648451).

Keywords: Continuous glucose monitoring; Hispanic/Latino adults; Pre-diabetes; Time in range; Type 2 diabetes.

Fig. 1

CGM wear time statistics for the participant cohort (n = 100). (a) Number of days participants wore a CGM device (b) Percentage of time CGM was active during wear time.

Fig. 2

Standardized CGM measures for n = 100 participants stratified by HbA_1c. Boxplots shown as median (red), interquartile range (blue edges) and total range (black tails). Outliers shown as red dots. P-values for pairwise comparisons computed using Tukey's HSD criterion (ns: not significant, *:p<0.05, ^⁎⁎:p<0.01, ^⁎⁎⁎:p<0.001, ^⁎⁎⁎⁎:p<0.0001). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Standardized CGM measures for at-risk (blue), pre-T2D (green), and T2D (red) participants computed separately for overnight (12am-6am) and rest of the day (6am-12am). The 45${}^{\circ }$ dotted line indicates equal values for overnight and rest of day; any participant below the line has a higher overnight value for that measure, whereas participants above the line have higher rest of the day values for that measure. %CV: Coefficient of variation expressed as a percentage value. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 4

Time in 140 to 180 mg/dL range stratified by group and time (overnight versus rest of day). At-risk participants denoted using blue dots, pre-T2D participants using green dots, and T2D participants using red dots. The 45${}^{\circ }$ dotted line indicates equal values for overnight and rest of day time in 140 to 180 mg/dL range. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 5

Relationship between overnight and rest of the day time in 70–140 mg/dL range with HbA_1c for all participants. Color bar representing HbA_1c values varies from 5.0% (dark blue) to 11.0% (dark red). The 45${}^{\circ }$ dotted line indicates equal values for overnight and rest of day time in 70–140 mg/dL range. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)