Preservation of Beta Cell Function in Autoantibody Positive Youth with Diabetes
- Carla J. Greenbaum, MD (cjgreen{at}benaroyaresearch.org)1,
- Andrea M. Anderson, MS2,
- Lawrence M. Dolan, MD3,
- Elizabeth J Mayer-Davis, PhD4,
- Dana Dabelea, MD, PhD5,
- Giuseppina Imperatore, MD, PhD6,
- Santica Marcovina, PhD7,
- Catherine Pihoker, MD8 and
- the SEARCH Study group
- 1. Diabetes Research Program, Benaroya Research Institute, Seattle, WA
- 2. Wake Forest University School of Medicine, Winston-Salem, NC
- 3. Cincinnati Children's Hospital and Medical Center, Cincinnati, OH
- 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. Department of Epidemiology, Colorado School of Public Health, University of Colorado Denver
- 6. Division of Diabetes Translation, National Center for Chronic Disease Prevention and Health Promotion Centers for Disease Control and Prevention Atlanta, GA
- 7. Department of Medicine, University of Washington, Seattle, WA
- 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
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- Received December 29, 2008.
- Accepted June 19, 2009.
- Copyright © American Diabetes Association
