What is the clinical evidence from this study?

Study design: Cohort. Population: Prediabetes or Type 2 Diabetes (n=6759145). Intervention: AABBCC criteria. Primary outcome: Reclassification to type 1 diabetes.

What does this research mean for the field?

Readily available clinical data such as age and BMI used in the ADA's proposed AABBCC criteria are insufficient to identify adult patients with type 1 diabetes, failing to identify approximately 75% of reclassified cases. Novelty: ClaimNovelty.CONTRADICTORY. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

What question did this study set out to answer?

This study aims to assess the effectiveness of the AABBCC criteria in reclassifying diabetes types among patients.

June 7, 2026

2231-P: RECLASS-T1D: Real-World Evaluation of AABBCC Criteria for Diabetes Classification: Experience from 6.7 Million U.S. Patients

Key Result

The AABBCC criteria failed to identify approximately 75% of patients reclassified to T1D, with only 1.6% of reclassified cases meeting both age <35 years and BMI <25 kg/m2 criteria.

Key Points

This study aims to assess the effectiveness of the AABBCC criteria in reclassifying diabetes types among patients.
Identified individuals in the US with prediabetes or type 2 diabetes diagnoses using TriNetX electronic health records.
Analyzed data availability for age, BMI, comorbidities, and HbA1c to evaluate AABBCC criteria applicability.
Followed up individuals from diagnosis of prediabetes or T2D until diagnosis of T1D, end of study, death, or loss to follow-up.
2.2% of individuals with prediabetes or T2D were reclassified as T1D.
Among individuals <35 years old, 5.1% were reclassified, constituting 23.6% of all reclassified cases.
Approximately 75% of individuals could not be identified using AABBCC criteria, revealing significant limitations.

Study Design

Type

Cohort (n=6,759,145)

Multicenter

Yes

Structured PICO

Population

6,759,145 individuals in the US with prediabetes or type 2 diabetes, evaluated for reclassification to type 1 diabetes using electronic health records.

Exposure

Application of the AABBCC criteria (Age <35 years, Autoimmunity, BMI <25 kg/m2, Background, Control, and Comorbidities) for diabetes classification

Outcome

Reclassification rates from prediabetes or type 2 diabetes to type 1 diabetes

The AABBCC criteria proposed by the ADA are insufficient to accurately identify adult patients with type 1 diabetes among those initially diagnosed with prediabetes or type 2 diabetes in real-world settings.

Limitations

Data availability for AABBCC criteria was limited in electronic health records (e.g., BMI 35.8%, comorbidities 9.7%, HbA1c 6.1%).
Overlap in clinical features makes differentiating T1D from T2D challenging.

Abstract

Introduction and Objective: The AABBCC approach (Age 35 years, Autoimmunity family or personal history, BMI 25 kg/m2, Background, Control not responding to oral agents, and Comorbidities) has been proposed by the American Diabetes Association to help distinguish between diabetes types. This study examined the reclassification rates from prediabetes or type 2 diabetes (T2D) to type 1 diabetes (T1D) and evaluated AABBCC criteria applicability. Methods: Individuals in the US with diagnosis codes for prediabetes (ICD-10-CM R73.09; R73.03; HbA1c 5.7–6.4%) or T2D (ICD-10-CM E11*) from July 2016 to October 2024 were identified using TriNetX electronic health records. Baseline was the 6 months before the first diagnosis of prediabetes or T2D. Follow-up was from the first prediabetes or T2D diagnosis until T1D diagnosis (ICD-10-CM E10*), end of study, death, or loss to follow-up. Results: Among 6,759,145 individuals with a prediabetes or T2D diagnosis, 2.2% were reclassified as having T1D. Data availability for AABBCC criteria was limited (age 100%, BMI 35.8%, comorbidities 9.7%, HbA1c 6.1%, autoimmune comorbidities 5.1%); thus, analyses focused on age and BMI. Among individuals 35 years of age, 5.1% (34,787 of 676,077) were reclassified as having T1D, representing 23.6% of all reclassified cases. Thus, most reclassified individuals were ≥35 years of age. Among those 35 years of age with BMI 25 kg/m2, 4.1% (2,353 of 57,325) were reclassified, accounting for only 1.6% of reclassified cases. Overall, approximately 75% of individuals could not be identified using AABBCC criteria, underscoring its limitations in differentiating T1D within this T2D/prediabetes population. Conclusion: Differentiating T1D from T2D remains challenging because of overlap in clinical features. These data suggest that readily available clinical data such as age and BMI are not sufficient to identify adult patients with T1D. Disclosure J. Shubrook: Advisory Panel; Current; Abbott Diabetes. Other - Doc Care Deputy EditorConsensus panel-liver health, screening early stage T1d, Technology in primary care; Current; American Diabetes Association. Advisory Panel; Current; Bayer AG, Boehringer Ingelheim International GmbH. Consultant; Ended; Corcept Therapeutics. Advisory Panel; Ended; Idorsia Pharmaceuticals Ltd. Advisory Panel; Current; Insulet Corporation. Advisory Panel; Ended; Madrigal Pharmaceuticals, Inc. Consultant; Current; Novo Nordisk, Sanofi. C.B. Manzano Salgado: Employee; Current; Sanofi. Employee; Ended; IQVIA Inc. M. Bonnemaire: Employee; Current; Sanofi. Stock/Shareholder; Current; Sanofi. L. Mk: None. A. Chopra: None. J. Dunne: Employee; Current; Sanofi-Aventis U.S. Employee; Ended; Novo Nordisk. L. Hao: Employee; Current; Sanofi. J. Pettus: None. P. Gottlieb: Consultant; Current; Eli Lilly and Company. Board Member; Current; IM Therapeutics. Other - CEO, CMO; Current; IM Therapeutics. Research Support; Current; Immune Tolerance Network, Nova Laboratories, National Institute of Diabetes and Digestive and Kidney Diseases. Advisory Panel; Current; Sanofi. Research Support; Current; Sanofi. Consultant; Current; SAB Biotherapeutics, Inc., Anaptys Bio, Cour, T1D Fund. Consultant; Ended; Imcyse, Viacyte, Abata.

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