Continuous Glucose Monitoring (CGM) has become an essential tool for managing diabetes, particularly for individuals with type 1 diabetes (T1D). One of the key metrics derived from CGM data is Time-in-Range (TIR), which reflects the percentage of time an individual’s glucose levels remain within a target range. Previous research has established that a higher TIR, specifically above 70%, is associated with lower HbA1c levels, a common measure of long-term glucose control.
This study, published in the Journal of Diabetes and Its Complications, investigates the relationship between TIR and HbA1c in youth with T1D, focusing on the impact of CGM sensor wear-time. The researchers categorized participants based on their CGM wear-time into two groups: those with ≥70% wear-time and those with <70% wear-time.
Methodology
The study involved 60 youth diagnosed with T1D. The researchers calculated Pearson correlations between TIR and HbA1c for both wear-time groups. They then compared these correlations using a Fisher r-to-z transformation to assess the strength of the association.
Results
The findings revealed significant correlations between TIR and HbA1c in both groups. For the group with ≥70% CGM wear-time, the correlation coefficient was r = -0.800 (p < .001), indicating a strong inverse relationship. In contrast, the group with <70% wear-time showed a weaker correlation of r = -0.404 (p < .001). The comparison of these correlations demonstrated a significantly stronger association in the ≥70% wear-time group (z = 3.15, p = .0016).
Conclusion
While the association between TIR and HbA1c was weaker in individuals with <70% CGM wear-time, the statistical significance suggests that even lower wear-time data may still provide useful insights for diabetes management. This finding is particularly relevant for clinicians and patients who may face challenges in maintaining consistent CGM use.
What this study does not show
This study does not establish a causal relationship between CGM wear-time and changes in HbA1c levels, nor does it address the long-term implications of varying wear-time on diabetes management.
Evidence scorecard
- Analytic validity: Established
- Clinical validity: Established
- Clinical utility: Not established
The evidence is based on primary research involving human participants.