title: HbA(1c) variability and the development of microalbuminuria in type 2 diabetes: Tsukuba Kawai Diabetes Registry 2.
abstract: OBJECTIVE
  The aim of this study was to examine the association between HbA(1c) variability and the development of microalbuminuria as defined by an albumin/creatinine ratio ≥ 3.4 mg/mmol (≥ 30 mg/g) in at least two of three consecutive urine samples in Japanese patients with type 2 diabetes.
  
  
  METHODS
  HbA(1c) level was measured in 812 serially registered normoalbuminuric adults aged 21-79 years with type 2 diabetes. After registration, a 1-year period to establish baseline values for mean HbA(1c) and HbA(1c) variability (measured as the intrapersonal SD of serially collected HbA(1c)) was decided upon. The association between HbA(1c) variability and the development of microalbuminuria was determined by Cox regression analysis after adjustment for other risk factors for microalbuminuria.
  
  
  RESULTS
  Microalbuminuria occurred in 193 patients during the observation period of (mean ± SD) 4.3 ± 2.7 years. Even after adjustment for mean HbA(1c), HbA(1c) variability was a significant predictor of microalbuminuria independently of the mean HbA(1c); the HR for every 1% (95% CI) increase in mean HbA(1c) was 1.22 (1.06, 1.40) (p = 0.005), and that for HbA(1c) variability was 1.35 (1.05, 1.72) (p = 0.019). The effects of these two variables were quite similar when 1 SD was used; the HR for every 1 SD increase (95% CI) in HbA(1c) was 1.23 (1.07, 1.43) (p = 0.005), and that for HbA(1c) variability was 1.20 (1.03, 1.39) (p = 0.019).
  
  
  CONCLUSIONS
  HbA(1c) variability affects the development of microalbuminuria independently of mean HbA(1c) in type 2 diabetes. Further studies should be performed to evaluate the influence of HbA(1c) variability on other complications and in individuals of other ethnicities with type 2 diabetes.
authors.affiliation: Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, 3-2-7 Miya-machi, Mito, Ibaraki, Japan, 310-0015.
authors.forename: A
authors.initials: A
authors.lastname: Sugawara
authors.forename: K
authors.initials: K
authors.lastname: Kawai
authors.forename: S
authors.initials: S
authors.lastname: Motohashi
authors.forename: K
authors.initials: K
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Kodama
authors.forename: Y
authors.initials: Y
authors.lastname: Yachi
authors.forename: R
authors.initials: R
authors.lastname: Hirasawa
authors.forename: H
authors.initials: H
authors.lastname: Shimano
authors.forename: K
authors.initials: K
authors.lastname: Yamazaki
authors.forename: H
authors.initials: H
authors.lastname: Sone
mesh_terms: D000419:Albuminuria / Q000652:urine*; D044466:Asian People; D001786:Blood Glucose / Q000378:metabolism; D003404:Creatinine / Q000652:urine*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000208:ethnology / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000097:blood* / Q000208:ethnology / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000097:blood* / Q000208:ethnology / Q000503:physiopathology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D012709:Serum Albumin / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D003404:Creatinine; D006442:Glycated Hemoglobin; D012709:Serum Albumin; C517652:hemoglobin A1c protein, human