ackground : HbA1c is formed slowly throughout the 120-day life span of the red blood cell by non-enzymatic glycosylation of HbA0 HbA1c concentrations reflect mean blood glucose levels over the previous several, weeks, but
we
experienced the changes of hemoglobin A1c values according to the short term changes of blood glucose levels. We investigated the changes of HbA1c values with a HPLC technique according to the short term changes of blood glucose
concentration.
Method : HbA1c values were measured at fasting and postprandial 2-hour state with a
HPLC method in 166 NIDDm patients, and they are divided into three groups
(GroupⅠ:HbAic<-0.3%, group Ⅱ:HbA1c>0.3%, group Ⅲ:-0.3≤HbAic≤0.3, HbA1c:postprandial 2
hour HbAlc values-fasting HbA1c values) and compared repectively. In 15 untreated
NIDDM patients, blood glucose and HbA1c were measured during the oral glucose
tloerance test to exclude the influence of food and treatment on the HPlC method. Stable
HbA1c and labile HbA1c were measured in 37 NIDDM patients to evaluate the influence of
labile HbAlc on the HPLC method.
Results:
1) in group Ⅰ,Ⅱ,Ⅲ Postprandial 2-hour blood glucose levels (man±SEM) were 185.1 ±
33.42 mg/dl, 306.3±13.69 mg/dl, 248.4±10.25 mg/dl, and significantly different respectively
(p<0.1). Fasting blood glucose levels, fasting HbA1c values and postprandial 2-hour HbA1c
values were not significantly different among three groups.
2) in group Ⅰ,Ⅱ,Ⅲ the differences between postprandial 2-hour levels and fasting blood
glucose levels were -79.8±43.79mg/dl, 103.2±14.61mg/dl, 42.9±11.17mg/dl, and the
differences were highly significant (p<0.001). The mean HbA1c values were -0.6±0.49%, 0.6±
0.33, 0.08±0.01% repectively.
3) in 15 untreated NIDDM patients, HbAi1 values were sighnificantly increased from 7.2±
1.3% to 7.8±1.9% according to the increment of blood glucose levels from 113±13.4 mg/dl to
222±3mg/dl (p<0.001).
4) labile HbA1c values measured in 37 NIDDM patients were significanly increased from 0.6
±0.08% at fasting state to 1.3±0.16% at postprandial 2-hour state according to the
increment of blood glucose levels from 164.1±9.61 mg/dl to 285.3±14.42 mg/dl (p<0.001), but
stable HbA1c values were not significantly changed.
5) correlation between labile HbA1c and blood glucose (r=0.41, p<0.001) was higher
than that between stable HbA1c and blood glucose (r=2.28, p<0.001).
Conclusion : from the above results we can find that HbA1c values measured with a
HPLC technique change according to the short term changes of blood glucose levels, and the
changes of HbA1c values are caused by the short term changes of labile HbA1c values.
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