title: Risk association of HbA1c variability with chronic kidney disease and cardiovascular disease in type 2 diabetes: prospective analysis of the Hong Kong Diabetes Registry.
abstract: BACKGROUND
  In type 2 diabetes, tight glycaemic control lowers the risk of diabetic complications, but it remains uncertain whether variability of glycaemia influences outcomes. We examined the association of glycated haemoglobin (HbA1c ) variability with incident chronic kidney disease and cardiovascular disease in a prospective cohort of 8439 Chinese patients with type 2 diabetes recruited from 1994 to 2007.
  
  
  METHODS
  Intrapersonal mean and SD of serially measured HbA1c were calculated. Chronic kidney disease was defined as estimated glomerular filtration rate <60 ml/min per 1.73 m². Cardiovascular disease was defined as events of ischemic heart disease, heart failure, ischemic stroke or peripheral vascular disease.
  
  
  RESULTS
  Over a median follow-up period of 7.2 years, 19.7 and 10.0% of patients developed chronic kidney disease and cardiovascular disease, respectively. Patients who progressed to chronic kidney disease had higher mean HbA1c (7.8 ± 1.3% vs 7.4 ± 1.2%, p < 0.001) and SD (1.0 ± 0.8% vs 0.8 ± 0.6%, p < 0.001) than nonprogressors. Similarly, patients who developed cardiovascular disease had higher mean HbA1c (7.7 ± 1.3% vs 7.4 ± 1.2%, p < 0.001) and SD (1.4 ± 1.1% vs 1.1 ± 0.8%, p < 0.001) than patients who did not develop cardiovascular disease. By using multivariate-adjusted Cox regression analysis, adjusted SD was associated with incident chronic kidney disease and cardiovascular disease with corresponding hazard ratios of 1.16 (95% CI 1.11-1.22), p < 0.001) and 1.27 (95% CI 1.15-1.40, p < 0.001), independent of mean HbA1c and other confounding variables.
  
  
  CONCLUSIONS
  Long-term glycaemic variability expressed by SD of HbA1c predicted development of renal and cardiovascular complications.
authors: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong SAR, China.
authors: Andrea O Y
authors: AO
authors: Luk
authors: Ronald C W
authors: RC
authors: Ma
authors: Eric S H
authors: ES
authors: Lau
authors: Xilin
authors: X
authors: Yang
authors: Winnie W Y
authors: WW
authors: Lau
authors: Linda W L
authors: LW
authors: Yu
authors: Francis C C
authors: FC
authors: Chow
authors: Juliana C N
authors: JC
authors: Chan
authors: Wing-Yee
authors: WY
authors: So
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000150:complications / Q000453:epidemiology* / Q000208:ethnology; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000175:diagnosis / Q000208:ethnology / Q000628:therapy; D003925:Diabetic Angiopathies / Q000453:epidemiology* / Q000208:ethnology; D058065:Diabetic Cardiomyopathies / Q000453:epidemiology* / Q000208:ethnology; D003928:Diabetic Nephropathies / Q000453:epidemiology* / Q000208:ethnology; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis*; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D006943:Hyperglycemia / Q000517:prevention & control; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012042:Registries; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000453:epidemiology* / Q000208:ethnology; D012307:Risk Factors
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: HbA1c variability; cardiovascular disease; chronic kidney disease; type 2 diabetes