Continuous Glucose Monitoring (CGM) has become an essential tool in 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 a person’s glucose levels remain within a target range. Previous research has indicated that a TIR greater than 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, specifically focusing on the impact of CGM sensor wear-time. The research involved 60 participants who were categorized based on their CGM wear-time: those with 70% or more wear-time and those with less than 70%.
Methodology
The researchers employed Pearson correlation coefficients to assess the relationship between TIR and HbA1c within each wear-time group. They then compared these correlations using a Fisher r-to-z transformation to determine if the strength of the association differed significantly between the two groups.
Results
The findings revealed that both groups exhibited significant correlations between TIR and HbA1c. In the group with ≥70% wear-time, the correlation coefficient was -0.800 (p < .001), indicating a strong inverse relationship. Conversely, the group with <70% wear-time showed a weaker correlation of -0.404 (p < .001). The statistical analysis confirmed that the association was significantly stronger in the ≥70% wear-time group (z = 3.15, p = .0016).
Conclusion
While the association between TIR and HbA1c was weaker in individuals with less than 70% CGM wear-time, the significant correlation suggests that data from lower wear-time can still provide valuable insights into glycemic control when necessary. This finding may encourage clinicians to consider CGM data even when wear-time is suboptimal.
What this study does not show
This study does not establish a causal relationship between CGM wear-time, TIR, and HbA1c levels, nor does it provide evidence on the long-term health outcomes associated with varying CGM wear-time.
Evidence scorecard
- Analytic validity: Established
- Clinical validity: Established
- Clinical utility: Not established
The evidence is based on primary research involving human participants.