A newer conversion equation for the correlation between HbA1c and glycated albumin

Glycated hemoglobin (HbA1c) and glycated albumin (GA) are frequently used as glycemic control markers. These markers are influenced by either altered hemoglobin metabolism or albumin metabolism. We investigated the correlation between HbA1c and GA by collecting only data that had not been affected by the turnover of either HbA1c or GA and proposed a novel equation for accurately estimating the extrapolated HbA1c (eHbA1c) value based on the GA value. Data sets for a total of 2461 occasions were obtained from 731 patients (including non-diabetes patients) whose HbA1c and GA values were simultaneously measured. Data sets obtained from patients undergoing hemodialysis, patients with hematological malignancies, pregnancy, chronic liver diseases, hyperthyroidism, steroid treatment or a blood transfusion during the past 3 months, or patients without albumin, hemoglobin, eGFR, or urinary protein measurements and data sets with an eGFR of less than 30 mL/min/1.73 m(2), a hemoglobin level of less than 10 mg/dL, an albumin level of below 3.0 g/mL, or a urinary protein level of 3+ were excluded. Finally, we selected 284 data sets. We then analyzed these data sets, performed a scatter plot to examine the correlation between HbA1c and GA, and established an equation describing the resulting correlation. Based on all the data points, the resulting equation was HbA1c = 0.216 × GA + 2.978 [R(2) = 0.5882, P < 0.001].