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New Diagnosing Criteria Possible for Type 1?

By closely examining currently used diagnostic criteria, researchers evaluated whether it might be possible to diagnose type 1 earlier….

Today, diagnostic criteria for type 1 diabetes includes a glucose value ≥ 126 mg/dL and 2-h glucose values ≥ 200 mg/dL. These glucose values were selected because they correspond with observed thresholds for the occurrence of diabetic retinopathy. But, these findings are usually seen in adults and not always appropriate for the pediatric population. This is predominantly applicable to type 1 diabetes, which usually happens in children. A recent study has been conducted to assess new diagnosed criteria for type 1 diabetes.

Researchers evaluated whether or not natural history in autoantibody-positive individuals can be diagnosed earlier compared to current diagnosing criteria.

The authors gathered data from the Diabetes Prevention Trial-Type 1 (DPT-1) and TrialNet Natural History Study (TNNHS) studies. Among these study populations, the authors used a metabolic index (index60), 2-h oral glucose tolerance tests (OGTTs), log fasting C-peptide, 60-min C-peptide, and 60-min glucose. OGTTs with index60 ≥ 2.00 and 2-h glucose < 200 mg/dL (Ind60+Only) were compared with index60 < 2.00 and 2-h glucose ≥ 200mg/dL (2hglu+Only) OGTTs as criteria for type 1 diabetes. All participants’ C-peptide loss from the first Ind60+Only OGTT to diagnosis was measured individually.

Results:

  • Index60 demonstrated significantly higher than for the 2-h glucose (P < 0.001 for both DPT-1 and the TNNHS)
  • Diagnostic criteria, sensitivity was higher for Ind60+Only compared to 2hglu+Only (0.44 vs 0.15 in DPT-1; 0.26 vs. 0.17 in the TNNHS) OGTTs
  • Specificity was likely higher for 2hglu+Only OGTTs in DPT-1 (0.97 vs. 0.91) but similar in the TNNHS (0.98 vs. 0.98)
  • Positive and negative predictive values were higher for Ind60+Only OGTTs in both studies
  • C-peptide levels declined at each OGTT time point from the standard diagnosis (Range -22 to -33% in DPT-1 and -14 to -27% in the TNNHS)
  • C-peptide and glucose patterns were different between Ind60+Only and 2hglu+Only OGTTS

The authors concluded that there may be a possibility of evolving a new diagnostic criteria based on prediction and natural history for type 1 diabetes.

Practice Pearls:

  • Based on prediction and natural history for individuals, type 1 diabetes may be diagnosed earlier in life.
  • This result only applies to autoantibody-positive relatives of type 1 diabetes patients.
  • More studies are necessary to confirm this result.

Sosenko JM, Skyler JS, DiMeglio LA, et al. A New Approach for Diagnosing Type 1 Diabetes in Autoantibody-Positive Individuals Based on Prediction and Natural History. Diabetes Care 2015; 38:271-276