Converse contributions of fasting and postprandial glucose to HbA1c and glycated albumin
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We evaluated the relationship between glycated hemoglobin (HbA1c) in diabetic patients with stable glycemic control and the average fasting blood glucose (FBG) and postprandial blood glucose (PPG) values of 4 weeks prior to HbA1c measurement and compared the results with glycated albumin (GA).
Research design and methods
Fifty-one diabetic patients were asked to use self-monitoring blood glucose to measure FBG before breakfast and PPG 1 and 2 h after breakfast 1 day a week for 4 weeks while maintaining normal daily activities. During monthly outpatient visits, HbA1c and GA were measured. Data were analyzed in 40 patients, with <1% variation in HbA1c values over 4 months.
HbA1c was best predicted by the average FBG (AvFBG) and the average of 1-h and 2-h PPG (AvMPPG) (adjusted R 2 = 0.51; HbA1c = 4.35 + 0.013 AvFBG + 0.0056 AvMPPG). The contribution ratio was 0.013:0.0056, showing about 2.3 times greater contribution by FBG. GA was best predicted by the AvFBG and the average of 2-h PPG (Av2hPPG) (adjusted R 2 = 0.55; GA = 9.36 + 0.0241 AvFBG + 0.0430 Av2hPPG). The contribution ratio was 0.024:0.043, showing about 1.8 times greater contribution by 2-h PPG. This converse contribution of fasting and postprandial glucose to HbA1c and GA was more prominent in insulin-treated patients than in untreated patients.
HbA1c and GA can be satisfactorily predicted by FBG and PPG. HbA1c reflects FBG more so than PPG, whereas GA better reflects PPG. Thus, depending on the characteristics of the glycated protein, a different glycemic status is reflected.
KeywordsHbA1c GA Postprandial blood glucose (PPG) Fasting blood glucose (FBG)
The costs for this study were allocated from the research expenses of Social Insurance Central General Hospital. The authors are grateful to Ms. Tomoko Chikami, Ms. Kazuko Mochizuki, and Ms. Satomi Ishida for their technical assistance. Parts of this study were presented in abstract and poster form at the 68th Scientific Sessions of the American Diabetes Association, San Francisco, California, 6–8 June 2008.
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