Clinical evaluation of measuring glycosylated hemoglobin levels for assessing the long-term blood glucose control in diabetics.

The glycosylated hemoglobin levels were determined in the hemolysates obtained from 14 normal subjects and 67 patients with adult-onset diabetes mellitus, using the column chromatographic procedure of Trivelli et al. The levels of hemoglobin A1a+b (HbA1a+b) and HbA1c and the sum of HbA1a+b and HbA1c (HbA1a+b+HbA1c) in normal subjects averaged 2.3 +/- 0.4 (SD)%, 5.3 +/- 0.8% and 7.6 +/- 1.0%, respectively. Although a slight increase in HbA1a+b was found in patients with diabetes mellitus (mean +/- SD=2.8 +/- 0.7%), it was not significantly different from that in normal subjects. Despite the wide range, HbA1c and HbA1a+b+HbA1c were significantly increased in patients with diabetes mellitus (6.9 +/- 1.8% for HbA1c, p < 0.01 and 9.7 +/- 2.2% for HbA1a+b+HbA1c, p < 0.01). A significant correlation existed between the glycosylated hemoglobins and plasma glucose levels determined in the same blood (r = +0.57, p < 0.001). Moreover, the glycosylated hemoglobin levels correlated significantly with the average glucose levels for several months preceding the hemoglobin measurements. In particular, a striking correlation was evident in the plots of HbA1a+b+HbA1c against the mean plasma glucose for 3 months prior to the hemoglobin measurements, which had a correlation coefficient of 0.79 (p < 0.001). The present findings revealed that the glycosylated hemoglobins reflect the time-averaged blood glucose levels in diabetics for during approximately the proceeding 3 months, indicating the usefulness of measuring the glycosylated hemoglobins in assessing the long-term blood glucose control in diabetics.