New continuous glucose monitoring (CGM) metrics may provide additional insight into glycemic variability beyond standard CGM indicators. A study published in Diabetes Technology & Therapeutics evaluated newly defined CGM metrics, including rebound hyperglycemia (RHyper), rebound hypoglycemia (RHypo), extended hyperglycemia (EHyper), and extended hypoglycemia (EHypo), and assessed their relationship with established CGM measures.

This retrospective cohort study analyzed CGM data from 30,000 users with at least 90 days of records in the Dexcom Clarity database. Standard and new CGM metrics were calculated for each user. Four thresholds were used to define RHyper and RHypo events, and two thresholds were used for EHyper and EHypo events. The number of events per week, mean event duration, and mean area under the curve were calculated. For rebound events, the rate of change (ROC) was also evaluated. Associations were assessed using Pearson correlation and linear regression.

Mean time in range (TIR, 70–180 mg/dL) was 61.8 ± 20.7%, mean glucose was 173 ± 37.1 mg/dL, and coefficient of variation (CV) was 32.1 ± 7.2%. RHyper, RHypo, and EHyper occurred more frequently during daytime and increased throughout the day, whereas EHypo occurred mainly during nighttime.

CV showed strong correlations with RHyper events/week (r = 0.67) and RHypo events/week (r = 0.64). TIR had the strongest correlation with EHyper events/week (r = −0.88). RHyper and RHypo events were strongly correlated with each other (r = 0.92). ROC for rebound events also showed stronger correlations with CV than the relationship between CV and time below range (TBR).

Overall, the number of rebound and extended events per week emerged as the most informative measure among the new CGM metrics. These findings suggest that rebound events may help identify hypoglycemia related to glycemic variability.