HbA^sub 1c^ variability and the development of microalbuminuria in type 2 diabetes: Tsukuba Kawai Diabetes Registry 2

• Published in: Diabetologia Vol. 55; no. 8; p. 2128
• Main Authors: Sugawara, A, Kawai, K, Motohashi, S, Saito, K, Kodama, S, Yachi, Y, Hirasawa, R, Shimano, H, Yamazaki, K, Sone, H
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer Nature B.V 01-08-2012
• Subjects: Creatinine; Diabetes; Diabetic neuropathy; Patients; Regression analysis; Risk factors; Urine; Japan
• ISSN: 0012-186X; 1432-0428
• DOI: 10.1007/s00125-012-2572-7

The aim of this study was to examine the association between HbA^sub 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. HbA^sub 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^sub 1c^ and HbA^sub 1c^ variability (measured as the intrapersonal SD of serially collected HbA^sub 1c^) was decided upon. The association between HbA^sub 1c^ variability and the development of microalbuminuria was determined by Cox regression analysis after adjustment for other risk factors for microalbuminuria. Microalbuminuria occurred in 193 patients during the observation period of (mean±SD) 4.3±2.7 years. Even after adjustment for mean HbA^sub 1c^, HbA^sub 1c^ variability was a significant predictor of microalbuminuria independently of the mean HbA^sub 1c^; the HR for every 1% (95% CI) increase in mean HbA^sub 1c^ was 1.22 (1.06, 1.40) (p=0.005), and that for HbA^sub 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^sub 1c^ was 1.23 (1.07, 1.43) (p=0.005), and that for HbA^sub 1c^ variability was 1.20 (1.03, 1.39) (p=0.019). HbA^sub 1c^ variability affects the development of microalbuminuria independently of mean HbA^sub 1c^ in type 2 diabetes. Further studies should be performed to evaluate the influence of HbA^sub 1c^ variability on other complications and in individuals of other ethnicities with type 2 diabetes.[PUBLICATION ABSTRACT]