P-17: RECLASS-T1D: real-world analysis of reclassification from type 2 diabetes or prediabetes to type 1 diabetes within a pediatric US cohort
J H Shubrook, A Chopra, L MK, J L Dunne, M Bonnemaire, C B Manzano-Salgado, P A Gottlieb, J PettusAbstract
Introduction
Misclassification of type 1 diabetes (T1D) as type 2 diabetes (T2D) occurs frequently in adults, but also occurs in youth, particularly given the rising cases of T2D in the pediatric population. Delayed identification of T1D, especially among misclassified youths, can hinder timely management and increase clinical risk.
Objectives
To determine the proportion and characteristics of youths reclassified to T1D after an initial diagnosis with T2D or prediabetes.
Methods
RECLASS-T1D was a retrospective US cohort study using EHR data from TriNetX that identified individuals <18 years (y) of age reclassified to T1D from 2016–2024. Index was the first date of diagnosis with T2D (ICD-10-CM E11*) or prediabetes (ICD-10-CM R73.09, R73.03; HbA1c 5.7–6.4%). Baseline was 6 months prior to index, and follow-up was until T1D diagnosis (ICD-10-CM E10*), loss to follow-up, end of study period, or death (whichever was first).
Results
Among 162,938 youths (median age 13y [IQR 10–15]), 11,412 (7%) were reclassified to T1D after an initial T2D or prediabetes diagnosis. Reclassification was higher among those initially diagnosed with T2D (13%) vs prediabetes (2%). Islet autoantibody (IAb) results were available for only 3,571 (2%) youths; of these, 1,812 (51%) were reclassified, increasing to 85% (241/283) among those with ≥2 positive IAbs. Kaplan-Meier estimates showed cumulative reclassification of 6% by 1y, ~8% by 3y, and 10% by 8y. Reclassified youths had greater healthcare resource utilization (HCRU) than non-reclassified peers: any HCRU (60% vs 20%), hospitalization (15% vs 1%), outpatient visits (26% vs 7%), and emergency department visits (9% vs 2%).
Conclusions
In this large US cohort, ~1 in 10 youths initially diagnosed with T2D or prediabetes were later reclassified to T1D. Limited IAb testing highlights missed opportunities for earlier T1D recognition. Systematic screening may help prevent delays in appropriate treatment and reduce HCRU among reclassified youths.