title: Association of variation range in glycated albumin (GA) with increase but not decrease in plasma glucose: implication for the mechanism by which GA reflects glycemic excursion.
abstract: OBJECTIVE
  HbA1c mainly reflects mean plasma glucose (PG), whereas glycated albumin (GA) reflects glycemic excursion in addition to mean PG; the mechanism of the difference between HbA1c and GA is unknown. We hypothesized that a transient increase in PG irreversibly produces stable GA unlike HbA1c. To prove this hypothesis, we investigated diurnal variations in PG, HbA1c, #C fraction (a fraction containing unstable HbA1c and modified hemoglobin on HPLC) and GA in diabetic patients.
  
  
  METHODS
  Sixteen diabetic patients with poor glycemic control were enrolled in this study. Blood sampling was performed before and after each meal, before bedtime, and before breakfast on the following day; PG, HbA1c, #C fraction, and GA were measured. The variations of these indicators were compared with those in PG.
  
  
  RESULTS
  HbA1c showed almost no change regardless of diurnal glycemic variation. Variation range in #C fraction significantly correlated with variation range in PG when PG increased (R=0.746, p<0.0001) and decreased (R=0.271, p=0.035). On the other hand, variation range in GA significantly correlated with variation range in PG when PG increased (R=0.322, p=0.021), but not when PG decreased (R=0.090, p=0.493).
  
  
  CONCLUSIONS
  We observed that variation range in GA significantly correlated with variation range in PG when PG increased but not when PG decreased for the first time. It is considered that GA reflects glycemic excursion through this phenomenon.
authors.affiliation: Department of Internal Medicine, NTT West Osaka Hospital, Osaka, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: Department of Internal Medicine, NTT West Osaka Hospital, Osaka, Japan.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Tanikawa
authors.affiliation: Department of Internal Medicine, NTT West Osaka Hospital, Osaka, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Nishikawa
authors.affiliation: Department of Internal Medicine, NTT West Osaka Hospital, Osaka, Japan.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, NTT West Osaka Hospital, Osaka, Japan.
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Internal Medicine, Kawanishi City Hospital, Hyogo, Japan. Electronic address: m-koga@kawanishi-city-hospital.com.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Koga
mesh_terms: D000368:Aged; D001786:Blood Glucose; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Glycated albumin; Glycemic excursion; HbA1c; Maillard reaction; Postprandial hyperglycemia