What question did this study set out to answer?

To evaluate the relationship between continuous glucose monitoring metrics and severe hypoglycemia events in type 1 diabetes.

March 18, 2026

The Virtual Diabetes Control and Complications Trial #4: Relationship of HbA1c and Continuous Glucose Monitoring Metrics with Severe Hypoglycemic Events

Key Points

To evaluate the relationship between continuous glucose monitoring metrics and severe hypoglycemia events in type 1 diabetes.
Developed virtual continuous glucose monitoring profiles from participants' glycemic data
Analyzed HbA1c and CGM metrics as predictors of severe hypoglycemia within 90 days
Employed Poisson regression models for statistical analysis
Evaluated the sensitivity and specificity of time-below-range for predicting hypoglycemic events
Participants with severe hypoglycemia had higher CGM measures and lower HbA1c compared to those without
Each 1% increase in time-below-range was associated with a 1.23 rate ratio for severe hypoglycemia
Each 0.5% increase in level 2 hypoglycemia corresponded to a 1.36 rate ratio for severe hypoglycemia
Despite associations, the time-below-range >6% had a low positive predictive value of 13% for severe hypoglycemia

Abstract

Objective: To evaluate how continuous glucose monitoring (CGM)-derived metrics relate to severe hypoglycemia (SH) events in individuals with type 1 diabetes by utilizing a multistep machine-learning approach to generate virtual CGM profiles from glycemic data in the Diabetes Control and Complications Trial (DCCT). Research Design and Methods: Virtual CGM profiles were created for each DCCT participant using previously validated methods. HbA1c values and CGM metrics were analyzed as predictors of SH events within the subsequent 90 days using Poisson regression models. Sensitivity, specificity, and positive predictive value of time-below-range (TBR) 6% demonstrated only 13% positive predictive value for SH events. Conclusion: Hypoglycemia-focused CGM metrics reproduced by virtual CGM data from the DCCT were strongly associated with SH events, although the positive predictive value was low.

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The Virtual Diabetes Control and Complications Trial #4: Relationship of HbA1c and Continuous Glucose Monitoring Metrics with Severe Hypoglycemic Events

Key Points

Abstract

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