title: Direct association of visit-to-visit HbA1c variation with annual decline in estimated glomerular filtration rate in patients with type 2 diabetes.
abstract: OBJECTIVE
  This study examined associations of visit-to-visit variability of glycemic control with annual decline in estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes attending an outpatient clinic.
  
  
  METHODS
  Intrapersonal mean and coefficient of variation (CV) of 8-12 measurements of HbA1c and those of 4-6 measurements of fasting and post-breakfast plasma glucose (FPG and PPG, respectively) during the first 12 months after enrollment were calculated in a cohort of 168 patients with type 2 diabetes. Annual changes in eGFR were computed using 52 (median) creatinine measurements obtained over a median follow-up of 6.0 years. Multivariate linear regressions assessed the independent correlates of changes in eGFR.
  
  
  RESULTS
  CV-HbA1c (standardized β、-0.257、p = 0.004) were significantly and log urine albumin/creatinine ratio (standardized β、-0.155、p = 0.085) and smoking (standardized β、-0.186、p = 0.062) tended to be associated with annual eGFR decline independently of mean HbA1c, age, sex, BMI, waist circumference, diabetes duration and therapy, means and CVs of FPG, PPG and systolic blood pressure, baseline eGFR, and uses of anti-hypertensive and lipid-lowering medications. Association between HbA1c variability and renal function decline was stronger in patients with albumin/creatinine ratio ≧ 30 mg/g than in those with normoalbuminuria (r = -0.400, p = 0.003 and r = -0.169, p = 0.07, respectively).
  
  
  CONCLUSIONS
  Consistency of glycemic control is important to preserve kidney function in type 2 diabetic patients, in particular, in those with nephropathy.
authors.affiliation: Postgraduate School of Food Sciences and Nutrition, Nishinomiya, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Takenouchi
authors.affiliation: Postgraduate School of Food Sciences and Nutrition, Nishinomiya, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Tsuboi
authors.affiliation: Department of Food Sciences and Nutrition, School of Human Environmental Sciences, Nishinomiya, Japan.
authors.forename: Mayu
authors.initials: M
authors.lastname: Terazawa-Watanabe
authors.affiliation: Department of Food Sciences and Nutrition, School of Human Environmental Sciences, Nishinomiya, Japan ; Research Institute for Nutrition Sciences, Mukogawa Women's University, 6-46, Ikebiraki-cho, Nishinomiya, Hyogo 663-8558 Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Kurata
authors.affiliation: Postgraduate School of Food Sciences and Nutrition, Nishinomiya, Japan ; Research Institute for Nutrition Sciences, Mukogawa Women's University, 6-46, Ikebiraki-cho, Nishinomiya, Hyogo 663-8558 Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Fukuo
authors.affiliation: Research Institute for Nutrition Sciences, Mukogawa Women's University, 6-46, Ikebiraki-cho, Nishinomiya, Hyogo 663-8558 Japan ; Diabetes Division, Sadamitsu Hospital, Kakogawa, Hyogo 675-0005 Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kazumi
keywords: HbA1c; Kidney function; Standard deviation; eGFR