When 7 isn't 7: glycohemoglobin and chronic kidney disease

Glycohemoglobin level (A1c) is widely viewed as the gold standard for assessing glycemic control. Clinical decisions are based upon it, and reimbursement is increasingly tied to it. However, there are a number of conditions which result in loss of correlation between A1c and mean blood glucose levels. Chronic kidney disease (CKD) is one condition, prevalent as a comorbidity with diabetes, that can result in an inaccurate impression of glycemic control based on measured A1c levels. We review the glycation of hemoglobin, how it is affected in CKD, and review alternative methods for the assessment of glycemic control in these patients.