Endocrinol Metab > Volume 28(4); 2013 > Article
Jung: Letter: A1c Variability Can Predict Coronary Artery Disease in Patients with Type 2 Diabetes with Mean A1c Level Greater than 7 (Endocrinol Metab 2013;28:125-32, Eun Ju Lee et al.)
Effects of hemoglobin A1c (HbA1c) variability on the microvascular and cardiovascular complications in type 1 diabetes have been reported. However, effect of HbA1c variability on coronary artery disease in type 2 diabetes was not described, especially when using such a sensitive diagnostic method like coronary angiography, as in the article by Lee et al. [1]. Therefore, although this is a retrospective observation study, we find that A1c variability as an independent predictor of coronary artery disease in type 2 diabetic patients with A1c level greater than 7% has great diagnostic value.
However, the authors did not present renal function or urine albumin excretion of the subjects, which can be important confounders in the study outcome. Not only advanced renal dysfunction, but also early change like microalbuminuria is well known as an independent factor of cardiovascular disease outcome [2]. In addition, it was recently reported that A1c variability was independently associated with the development of microalbuminuria in patients with type 2 diabetes [3]. Therefore, additional analysis including renal status might demonstrate a more clear relationship between A1c variability and coronary artery disease. Soon after the publication by Lee et al. [1], a contrary result was released that A1c variability had no major impact on macrovascular complications in patients with type 2 diabetes, which is in opposition to nephropathy [4].


No potential conflict of interest relevant to this article was reported.


1. Lee EJ, Kim YJ, Kim TN, Kim TI, Lee WK, Kim MK, Park JH, Rhee BD. A1c variability can predict coronary artery disease in patients with type 2 diabetes with mean A1c levels greater than 7. Endocrinol Metab 2013;28:125-132.
2. Mann JF, Gerstein HC, Pogue J, Bosch J, Yusuf S. Renal insufficiency as a predictor of cardiovascular outcomes and the impact of ramipril: the HOPE randomized trial. Ann Intern Med 2001;134:629-636.
3. Hsu CC, Chang HY, Huang MC, Hwang SJ, Yang YC, Lee YS, Shin SJ, Tai TY. HbA1c variability is associated with microalbuminuria development in type 2 diabetes: a 7-year prospective cohort study. Diabetologia 2012;55:3163-3172.
4. Penno G, Solini A, Zoppini G, Orsi E, Fondelli C, Zerbini G, Morano S, Cavalot F, Lamacchia O, Trevisan R, Vedovato M, Pugliese G. Renal Insufficiency and Cardiovascular Events (RIACE) Study Group. Hemoglobin A1c variability as an independent correlate of cardiovascular disease in patients with type 2 diabetes: a cross-sectional analysis of the renal insufficiency and cardiovascular events (RIACE) Italian multicenter study. Cardiovasc Diabetol 2013;12:98

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