title: Optimal hemoglobin A1C Cutoff Value for Diagnosing type 2 diabetes mellitus in Korean adults.
abstract: Commonly used tests for the diagnosis of diabetes include measurements of fasting plasma glucose levels and the oral glucose tolerance test (OGTT). Recently, a hemoglobin A1C (A1C) level of 6.5% has been included as a criterion for diabetes diagnosis by the American Diabetes Association. We aimed to determine appropriate A1C cutoff values for identifying patients with diabetes or prediabetes, including impaired glucose tolerance and impaired fasting glucose among Korean adults and to determine whether these cutoffs vary according to age. We recruited 4616 adults without a history of diabetes from 10 university hospitals. A 75-g OGTT and A1C sampling were performed in all examinees. Pointwise area under the receiver operating characteristic curve was used to evaluate the diagnostic accuracy of the A1C cutoff. An A1C threshold of 6.1% proved to be the optimal limit for diagnosing diabetes, with 63.8% sensitivity and 88.1% specificity. The cutoff value increased with age (5.9% in 18-39 years, 6.2% in 40-64 years, and 6.4% in older than 65 years) and were similar for men and women. An A1C cutoff of 5.7% had reasonable sensitivity (48.6%) and specificity (65.7%) for the identification of prediabetes. Further prospective studies should be carried out to determine whether the application of age-specific diagnostic criteria is appropriate.
authors.affiliation: Department of Internal Medicine, Ewha Womans University School of Medicine, Republic of Korea.
authors.forename: Hyejin
authors.initials: H
authors.lastname: Lee
authors.forename: Jee-Young
authors.initials: JY
authors.lastname: Oh
authors.forename: Yeon-Ah
authors.initials: YA
authors.lastname: Sung
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: Kim
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Sin-Gon
authors.initials: SG
authors.lastname: Kim
authors.forename: Sungdae
authors.initials: S
authors.lastname: Moon
authors.forename: Ie-Byung
authors.initials: IeB
authors.lastname: Park
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Rhee
authors.forename: Choon-Hee
authors.initials: CH
authors.lastname: Chung
authors.forename: Byung-Joon
authors.initials: BJ
authors.lastname: Kim
authors.forename: Bon-Jeong
authors.initials: BJ
authors.lastname: Ku
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis*; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin; D006801:Humans; D055815:Young Adult
chemical_list: D006442:Glycated Hemoglobin