Endocrine Abstracts (2014) 35 P384 | DOI: 10.1530/endoabs.35.P384

Translating the A1C assay into estimated average fasting glucose values: Data from the 2011 Korea National Health and Nutrition Examination Survey V

Jun Goo Kang, Jung Hun Ohn, Ju Ri Park, Sung Hoon Yu, Ohk Hyun Ryu, Chul Sik Kim, Seong Jin Lee, Eun Gyoung Hong, Doo-Man Kim, Jae Myung Yoo, Sung Hee Ihm, Moon Gi Choi & Hyung Joon Yoo

Hallym University College of Medicine, Chuncheon, Republic of Korea.

Aim: An international expert committee, after considering data on association of HbA1c and retinopathy, recommended that diabetes be diagnosed when HbA1c is more than 48 mmol/mol (>6.5%), provided this assay is done in a standardized laboratory. However, the performance of HbA1c in detecting diabetes in the Korean population remains unknown. The purpose of this study was to evaluate the efficiency of HbA1c in diagnosing diabetes and to identify the optimal threshold in the adult Korean population by using high performance liquid chromatography.

Methods: We analyzed data for an initial total of 8,518 men and women, 6,066 persons (2,677 men and 3,389 women), with HbA1c and fasting glucose data and without diabetes medication from 2011 KNHANES. We investigated the association in fasting blood glucose and HbA1c and the difference in the diagnosis of diabetes, based on the health interview and health examination data of KNHANES V. The threshold for the diagnosis of diabetes was 126 mg/dl and more by fasting blood glucose level and 6.5% or higher by hemoglobin A1c level.

Results: Proportions of persons with diabetes person (suggested definition of fasting blood glucose and HbA1c) were 2.5 and 3.3%, respectively, in this study populations. Percentages of persons with diabetes by fasting glucose but not HbA1c were 0.9% and percentages of persons with diabetes by HbA1c but not fasting glucose were 1.7%. The Pearson correlation coefficient (r) was 0.83. The change in HbA1c per increase of 10 mg/dl fasting blood glucose was 0.25% which was similar previous result but fasting blood glucose 101 mg/dl predicted HbA1c 6.5%.

Conclusions: An HbA1c threshold of 6.5% was highly specific for detecting undiagnosed diabetes in Korean adults and had sensitivity similar to that of using a fasting plasma glucose threshold of 126 mg/dl. This optimal HbA1c threshold may be suitable as a diagnostic criterion for diabetes in Korean adults when fasting plasma glucose is not available.