Possible discrepancy of HbA1c values and its assessment among patients with chronic renal failure, hemodialysis and other diseases

BACKGROUND: Glycated hemoglobin (HbA1c) and glycated albumin (GA) are frequently used as glycemic control markers. However, these markers are influenced by alterations in hemoglobin and albumin metabolism. Thus, conditions such as anemia, chronic renal failure, hypersplenism, chronic liver diseases, hyperthyroidism, hypoalbuminemia, and pregnancy need to be considered when interpreting HbA1c or GA values. Using data from patients with normal albumin and hemoglobin metabolism, we previously established a linear regression equation describing the GA value versus the HbA1c value to calculate an extrapolated HbA1c (eHbA1c) value for the accurate evaluation of glycemic control. In this study, we investigated the difference between the measured HbA1c and the eHbA1c values for patients with various conditions. METHODS: Data sets for a total of 2461 occasions were obtained from 731 patients whose HbA1c and GA values were simultaneously measured. We excluded patients with missing data or changeable HbA1c levels, and patients who had received transfusions or steroids within the previous 3 months. Finally, we included 44 patients with chronic renal failure (CRF), 10 patients who were undergoing hemodialysis (HD), 7 patients with hematological malignancies and a hemoglobin level of less than 10 g/dL (HM), and 12 patients with chronic liver diseases (CLD). RESULTS: In all the groups, the eHbA1c values were significantly higher than the measured HbA1c values. The median difference was 0.75 % (95 % CI 0.40–1.10 %, P for the difference is <0.001) in the CRF group, 0.80 % (95 % CI 0.30–1.65 %, P for the difference is 0.041) in the HD group, 0.90 % (95 % CI 0.90–1.30 %, P for the difference is 0.028) in the HM group, and 0.85 % (95 % CI 0.40–1.50 %, P for the difference is 0.009) in the CLD group. CONCLUSIONS: We found that the measured HbA1c values were lower than the eHbA1c values in each of the groups.