The association between estimated average glucose levels and fasting plasma glucose levels.
OBJECTIVE
The level of hemoglobin A1c (HbA1c), also known as glycated hemoglobin, determines how well a patient's blood glucose level has been controlled over the previous 8-12 weeks. HbA1c levels help patients and doctors understand whether a particular diabetes treatment is working and whether adjustments need to be made to the treatment. Because the HbA1c level is a marker of blood glucose for the previous 120 days, average blood glucose levels can be estimated using HbA1c levels. Our aim in the present study was to investigate the relationship between estimated average glucose levels, as calculated by HbA1c levels, and fasting plasma glucose levels.


METHODS
The fasting plasma glucose levels of 3891 diabetic patient samples (1497 male, 2394 female) were obtained from the laboratory information system used for HbA1c testing by the Department of Internal Medicine at the Izmir Bozyaka Training and Research Hospital in Turkey. These samples were selected from patient samples that had hemoglobin levels between 12 and 16 g/dL. The estimated glucose levels were calculated using the following formula: 28.7 x HbA1c - 46.7. Glucose and HbA1c levels were determined using hexokinase and high performance liquid chromatography (HPLC) methods, respectively.


RESULTS
A strong positive correlation between fasting plasma glucose levels and estimated average blood glucose levels (r=0.757, p<0.05) was observed. The difference was statistically significant.


CONCLUSIONS
Reporting the estimated average glucose level together with the HbA1c level is believed to assist patients and doctors determine the effectiveness of blood glucose control measures.
Izmir Bozyaka Training and Research Hospital, Turkey. giraybozkaya@yahoo.com
Giray
G
Bozkaya
Emrah
E
Ozgu
Baysal
B
Karaca
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000097:blood* / Q000517:prevention & control; D005215:Fasting / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D013997:Time Factors; D055815:Young Adult
D001786:Blood Glucose; D006442:Glycated Hemoglobin
Diabetes Care. 2008 Aug;31(8):1473-8
18540046
Diabetes Care. 2002 Sep;25(9):1551-6
12196426
Clinics (Sao Paulo). 2009;64(11):1093-8
19936183
Diabetes Care. 2008 Aug;31(8):1704-7
18540045
Diabetes Care. 2002 Feb;25(2):275-8
11815495
Clin Chem. 2002 Mar;48(3):436-72
11861436
Diabetes Care. 2009 Jan;32(1):e10; author reply e12
19114619
Diabetes Care. 2010 Jan;33 Suppl 1:S11-61
20042772
Lancet. 1998 Sep 12;352(9131):837-53
9742976
Diabetes Care. 2009 Jan;32(1):e11; author reply e12
19114620
Diabetologia. 2007 Nov;50(11):2239-44
17851648
Diabetes Care. 2002 Nov;25(11):2110-1
12401772