Topic Highlight
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Feb 15, 2015; 6(1): 17-29
Published online Feb 15, 2015. doi: 10.4239/wjd.v6.i1.17
Utility of different glycemic control metrics for optimizing management of diabetes
Klaus-Dieter Kohnert, Peter Heinke, Lutz Vogt, Eckhard Salzsieder
Klaus-Dieter Kohnert, Peter Heinke, Eckhard Salzsieder, Institute of Diabetes “Gerhardt Katsch”, D-17495 Karlsburg, Germany
Lutz Vogt, Diabetes Service Center, D-17495 Karlsburg, Germany
Author contributions: Kohnert KD drafted the manuscript, contributed to revision of the manuscript for intellectual content and approval of the manuscript; Heinke P contributed to analysis and interpretation of data; Vogt L contributed to interpretation of data and revision of the manuscript for intellectual content; Salzsieder E is the guarantor of this work and, as such, takes responsibility for its integrity and accuracy.
Conflict-of-interest: All authors declare no conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Klaus-Dieter Kohnert, MD, PhD, Institute of Diabetes “Gerhardt Katsch”, Greifswalder Str. 11a, D-17495 Karlsburg, Germany.
Telephone: +49-383-5568406 Fax: +49-383-5568444
Received: August 26, 2014
Peer-review started: August 28, 2014
First decision: September 19, 2014
Revised: September 26, 2014
Accepted: December 1, 2014
Article in press: December 1, 2014
Published online: February 15, 2015

The benchmark for assessing quality of long-term glycemic control and adjustment of therapy is currently glycated hemoglobin (HbA1c). Despite its importance as an indicator for the development of diabetic complications, recent studies have revealed that this metric has some limitations; it conveys a rather complex message, which has to be taken into consideration for diabetes screening and treatment. On the basis of recent clinical trials, the relationship between HbA1c and cardiovascular outcomes in long-standing diabetes has been called into question. It becomes obvious that other surrogate and biomarkers are needed to better predict cardiovascular diabetes complications and assess efficiency of therapy. Glycated albumin, fructosamin, and 1,5-anhydroglucitol have received growing interest as alternative markers of glycemic control. In addition to measures of hyperglycemia, advanced glucose monitoring methods became available. An indispensible adjunct to HbA1c in routine diabetes care is self-monitoring of blood glucose. This monitoring method is now widely used, as it provides immediate feedback to patients on short-term changes, involving fasting, preprandial, and postprandial glucose levels. Beyond the traditional metrics, glycemic variability has been identified as a predictor of hypoglycemia, and it might also be implicated in the pathogenesis of vascular diabetes complications. Assessment of glycemic variability is thus important, but exact quantification requires frequently sampled glucose measurements. In order to optimize diabetes treatment, there is a need for both key metrics of glycemic control on a day-to-day basis and for more advanced, user-friendly monitoring methods. In addition to traditional discontinuous glucose testing, continuous glucose sensing has become a useful tool to reveal insufficient glycemic management. This new technology is particularly effective in patients with complicated diabetes and provides the opportunity to characterize glucose dynamics. Several continuous glucose monitoring (CGM) systems, which have shown usefulness in clinical practice, are presently on the market. They can broadly be divided into systems providing retrospective or real-time information on glucose patterns. The widespread clinical application of CGM is still hampered by the lack of generally accepted measures for assessment of glucose profiles and standardized reporting of glucose data. In this article, we will discuss advantages and limitations of various metrics for glycemic control as well as possibilities for evaluation of glucose data with the special focus on glycemic variability and application of CGM to improve individual diabetes management.

Keywords: Markers of glycemic control, Hemoglobin A1c, Postprandial glucose, Risk of hyperglycemia and hypoglycemia, Continuous glucose monitoring, Glycemic variability, Glucose dynamics, Standardization, Diabetes mellitus

Core tip: Hemoglobin A1c is the gold standard to assess glycemic control and a surrogate for diabetes-associated complications. Self-monitoring of blood glucose complements daily diabetes management but is insufficient in providing complete information on short-term changes in glucose levels induced by effects of food or antidiabetic medication. Key metrics beyond HbA1c are needed for glycemic control on a day-to-day basis as well as more advanced monitoring methods. Herein, we will review advantages and limitations of different metrics for glycemic control as well as possibilities for characterization of glucose dynamics with the special focus on glycemic variability and continuous glucose monitoring.