title: A1C Combined With Glycated Albumin Improves Detection of Prediabetes in Africans: The Africans in America Study.
abstract: OBJECTIVE
  Slowing the diabetes epidemic in Africa requires improved detection of prediabetes. A1C, a form of glycated hemoglobin A, is recommended for diagnosing prediabetes. The glycated proteins, fructosamine and glycated albumin (GA), are hemoglobin-independent alternatives to A1C, but their efficacy in Africans is unknown. Our goals were to determine the ability of A1C, fructosamine, and GA to detect prediabetes in U.S.-based Africans and the value of combining A1C with either fructosamine or GA.
  
  
  METHODS
  Oral glucose tolerance tests (OGTT) were performed in 217 self-identified healthy African immigrants (69% male, age 39 ± 10 years [mean ± SD], BMI 27.6 ± 4.5 kg/m(2)). A1C, fructosamine, and GA were measured. Prediabetes was diagnosed by American Diabetes Association criteria for glucose obtained from a 2-h OGTT. The thresholds to diagnose prediabetes by A1C, fructosamine, and GA were the cutoff at the upper tertile for each variable: ≥5.7% (39 mmol/mol) (range 4.2-6.6% [22.4-48.6 mmol/mol]), ≥230 µmol/L (range 161-269 µmol/L), and ≥13.35% (range 10.20-16.07%), respectively.
  
  
  RESULTS
  Prediabetes occurred in 34% (74 of 217). The diagnostic sensitivities of A1C, fructosamine, and GA were 50%, 41%, and 42%, respectively. The P values for comparison with A1C were both >0.3. Combining A1C with either fructosamine or GA increased sensitivities. However, the sensitivity of A1C combined with fructosamine was not better than for A1C alone (72% vs. 50%, P = 0.172). In contrast, the sensitivity of A1C combined with GA was higher than for A1C alone (78% vs. 50%, P < 0.001).
  
  
  CONCLUSIONS
  As individual tests, A1C, fructosamine, and GA detected ≤50% of Africans with prediabetes. However, combining A1C with GA made it possible to identify nearly 80% of Africans with prediabetes.
authors.affiliation: Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD annes@intra.niddk.nih.gov.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Sumner
authors.affiliation: Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
authors.forename: Michelle T
authors.initials: MT
authors.lastname: Duong
authors.affiliation: Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
authors.forename: Paola C
authors.initials: PC
authors.lastname: Aldana
authors.affiliation: Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
authors.forename: Madia
authors.initials: M
authors.lastname: Ricks
authors.affiliation: Tropical Medicine Research Institute, The University of the West Indies, Kingston, Jamaica.
authors.forename: Marshall K
authors.initials: MK
authors.lastname: Tulloch-Reid
authors.affiliation: Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD.
authors.forename: Jay N
authors.initials: JN
authors.lastname: Lozier
authors.affiliation: Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: Chung
authors.affiliation: Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD.
authors.forename: David B
authors.initials: DB
authors.lastname: Sacks
mesh_terms: D000328:Adult; D000349:Africa; D044383:Black People; D001786:Blood Glucose / Q000378:metabolism; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000175:diagnosis; D054242:Emigrants and Immigrants; D005260:Female; D019270:Fructosamine / Q000097:blood*; D005947:Glucose; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D017127:Glycation End Products, Advanced; D006801:Humans; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000175:diagnosis* / Q000208:ethnology; D012709:Serum Albumin / Q000032:analysis*; D014481:United States; D000093423:Glycated Serum Albumin; D001741:Black or African American
chemical_list: D001786:Blood Glucose; D019270:Fructosamine; D005947:Glucose; D006442:Glycated Hemoglobin; D017127:Glycation End Products, Advanced; D012709:Serum Albumin; D000093423:Glycated Serum Albumin; C517652:hemoglobin A1c protein, human