Preservation of Beta Cell Function in Autoantibody Positive Youth with Diabetes

  1. Carla J. Greenbaum, MD (cjgreen{at}benaroyaresearch.org)1,
  2. Andrea M. Anderson, MS2,
  3. Lawrence M. Dolan, MD3,
  4. Elizabeth J Mayer-Davis, PhD4,
  5. Dana Dabelea, MD, PhD5,
  6. Giuseppina Imperatore, MD, PhD6,
  7. Santica Marcovina, PhD7,
  8. Catherine Pihoker, MD8 and
  9. the SEARCH Study group
  1. 1. Diabetes Research Program, Benaroya Research Institute, Seattle, WA
  2. 2. Wake Forest University School of Medicine, Winston-Salem, NC
  3. 3. Cincinnati Children's Hospital and Medical Center, Cincinnati, OH
  4. 4. Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC and Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC
  5. 5. Department of Epidemiology, Colorado School of Public Health, University of Colorado Denver
  6. 6. Division of Diabetes Translation, National Center for Chronic Disease Prevention and Health Promotion Centers for Disease Control and Prevention Atlanta, GA
  7. 7. Department of Medicine, University of Washington, Seattle, WA
  8. 8. Department of Pediatrics, University of Washington, Seattle, WA

    Abstract

    Objective: Determine the extent of beta cell function in youth with diabetes and GAD65 and/or IA2 autoantibodies.

    Methods: Fasting C-peptide levels from 2789 GAD65 and/or IA2 autoantibody positive youth aged 1-23 years from the SEARCH for Diabetes in Youth study. Preserved beta cell function was defined based on cut points derived from the Diabetes Control and Complications Trial (fasting C-peptide ≥ 0.23 ng/ml) and from the US adolescent population of the National Health and Nutrition Examination Survey (NHANES), 5th percentile for fasting C-peptide (≥1.0 ng/ml). We compared the clinical characteristics between those with and without preserved beta cell function.

    Results: Within the first year of diagnosis, 82.9% of youth had a fasting C-peptide ≥ 0.23 ng/ml and 31.2% had values ≥1.0 ng/ml. Among those with ≥5 years of diabetes duration, 10.7% had preserved beta-cell function based on the DCCT cutoff and 1.0% were above the 5th percentile of the NHANES population.

    Conclusion: Within the first year of diagnosis, four out of five youth with autoantibody positive diabetes have clinically significant amounts of residual beta cell function and about a third have fasting C-peptide levels above the 5th percentile of a healthy adolescent population. Even five years after diagnosis, one out of ten has fasting C-peptide above a clinically significant threshold. These findings have implications for clinical classification of youth with diabetes as well as clinical trials aimed at preserving beta-cell function after diabetes onset.

    Footnotes

      • Received December 29, 2008.
      • Accepted June 19, 2009.

    This Article

    1. Diabetes Care
    1. All Versions of this Article:
      1. dc08-2326v1
      2. 32/10/1839 most recent