Repeated OGTT Versus Continuous Glucose Monitoring for Predicting Development of Stage 3 Type 1 Diabetes: A Longitudinal Analysis
Authors' conclusion
In longitudinal models, repeated CGM and HbA1c were nearly as effective as OGTT in predicting stage 3 type 1 diabetes and may be more convenient for long-term clinical monitoring.
Study context
- Population
- Multiple autoantibody-positive first-degree relatives (BMI SD score <2) with presymptomatic T1D; baseline median age 16.6 years197 oral glucose tolerance tests (OGTTs) with continuous glucose monitoring (CGM)
- Participants
- 34 relatives
- Comparison
- Repeated CGM vs HbA1c vs OGTT metrics for predicting progression to stage 3 T1D
- Outcome
- Prediction of rapid (<3 years) and overall progression to stage 3 T1D
- Follow-up
- Median 3.5 (IQR 2.0-7.5) years
Methodological detailsmulticenter
- Multicenter
Performance
As reported in the abstract
Prediction of progression to stage 3 T1D in longitudinal models (AICc)
| Test or model | AICc (AUC glucose) | AICc (best CGM metric) | AICc |
|---|---|---|---|
| OGTT | 71 | ||
| CGM | 75 | ||
| HbA1c | 80 |
AICc (AUC glucose)
OGTT71
CGM— not stated in the abstract
HbA1c— not stated in the abstract
AICc (best CGM metric)
OGTT— not stated in the abstract
CGM75
HbA1c— not stated in the abstract
AICc
OGTT— not stated in the abstract
CGM— not stated in the abstract
HbA1c80
- OGTT-derived AUC glucose outperformed the best CGM metric and HbA1c
- all P < 0.001
- HbA1c combined with repeated CGM metrics, AICc
- 68
- OGTT-based multivariable models, AICc
- 59
Further findings
Progression to stage 3 T1D · median 40 (IQR 20-91) months
- First-degree relatives (FDRs) developing stage 3 T1D
- 17 of 34
Cross-sectional prediction by best OGTT and CGM metrics
- Rapid progression, ROC AUC
- 0.86-0.92
- Overall progression, concordance
- 0.73-0.78
- Best OGTT and CGM metrics predicted similarly
Longitudinal patterns
- CGM metrics increased close to onset, paralleling OGTT changes, with substantial intra- and interindividual variability
Original publication
Repeated OGTT Versus Continuous Glucose Monitoring for Predicting Development of Stage 3 Type 1 Diabetes: A Longitudinal Analysis. Diabetes Care. Published 4 February 2025. doi:10.
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