Introduction & Objective: Classification of diabetes (DM) type (T1D vs T2D) is often challenging in adolescence, especially among non-White ethnic groups. We hypothesized that pCP differentiates between provider-diagnosed T1D and T2D in ethnically diverse youth with DM. Methods: We studied 410 youth in the Diabetes Study in Children of Diverse Ethnicity and Race (DISCOVER) Study. Low C-peptide, pre-defined as pCP < 1.8 ng/ml (0.6 nmol/L) was compared between youth diagnosed with T1D and T2D using Fisher’s exact tests. Differences in the distribution of log pCP were assessed visually with histograms.
Results: There were 356 youth diagnosed with T1D (age 8.4 ± 3.1 yrs; 55% female; 36% Hispanic, 19% non-Hispanic Black) and 54 (13%) with T2D (age 11.7 ±1.7 yrs; 71% female; 70% Hispanic, 21.4% non-Hispanic Black). Low pCP was observed in 97.8% of T1D vs 27.1% of T2D youth (p<0.0001); 99.6% (T1D) vs 24.0% (T2D) (p<0.0001) in those with DM duration >4 yrs; 97.2% (T1D) vs 22.2% (T2D) (p<0.0001) in those with simultaneous glucose >115 mg/dl (6.4 mmol/L); and 99.5% (T1D) vs 11.1% (T2D) (<0.0001) in those with DM for >4 yrs and glucose >115 mg/dl (Figure).
Conclusion: In ethnically diverse youth, pCP <1.8 ng/ml can reliably identify those with provider-diagnosed T1D. Performance further improves in youth with DM duration >4 yrs and a simultaneous glucose >115 mg/dl. A sizeable subset of youth with T2D have lower pCP.
M.J. Redondo: None. K.K. Harrall: None. S.M. Bird: None. M. Tosur: None. S. Uysal: None. A.F. Siller: None. H.J. Velasquez: None. A. Muir: None. K. Vehik: None. T.M. Brusko: None. M.A. Atkinson: None. D. Dabelea: None. W. Hagopian: Research Support; Janssen Pharmaceuticals, Inc., Provention Bio, Inc. Consultant; Sanofi-Aventis U.S., Randox R & D. R.A. Oram: Research Support; Randox R & D. Consultant; Provention Bio, Inc., Sanofi.
National Institutes of Health (NIDDK R01DK124395)
