Risk association of HbA1c variability with chronic kidney disease and cardiovascular disease in type 2 diabetes: prospective analysis of the Hong Kong Diabetes Registry

Diabetes Metab Res Rev. 2013 Jul;29(5):384-90. doi: 10.1002/dmrr.2404.

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.

Keywords: HbA1c variability; cardiovascular disease; chronic kidney disease; type 2 diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cardiovascular Diseases / complications
  • Cardiovascular Diseases / epidemiology*
  • Cardiovascular Diseases / ethnology
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / complications*
  • Diabetes Mellitus, Type 2 / diagnosis
  • Diabetes Mellitus, Type 2 / ethnology
  • Diabetes Mellitus, Type 2 / therapy
  • Diabetic Angiopathies / epidemiology*
  • Diabetic Angiopathies / ethnology
  • Diabetic Cardiomyopathies / epidemiology*
  • Diabetic Cardiomyopathies / ethnology
  • Diabetic Nephropathies / epidemiology*
  • Diabetic Nephropathies / ethnology
  • Female
  • Follow-Up Studies
  • Glycated Hemoglobin A / analysis*
  • Hong Kong / epidemiology
  • Humans
  • Hyperglycemia / prevention & control
  • Incidence
  • Male
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Registries
  • Renal Insufficiency, Chronic / complications
  • Renal Insufficiency, Chronic / epidemiology*
  • Renal Insufficiency, Chronic / ethnology
  • Risk Factors

Substances

  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human