Diagnostic accuracy of glycohemoglobin A1c (HbA1c) for postprandial hyperglycemia was equivalent to that of fasting blood glucose.
OBJECTIVE
To compare the sensitivity, specificity, and total accuracy of an HbA1c of > or =6.5% in the detection of hyperglycemia (PPHG) relative to those of a fasting blood glucose (FBG) of > or =7.0 mmol/L.


METHODS
A total of 6,010 subjects (2,987 men and 3,023 women) living or working in Kasugai, Japan, underwent a medical checkup at Kasugai City Medical Care Center between April 2001 and March 2002. For the 91 subjects who had either a FBG of > or =7.0 mmol/L or an HbA1c of > or =6.5%, a 75-g oral glucose tolerance test was performed to confirm or exclude PPHG. We calculated the true- and false-positive odds ratios to evaluate the sensitivity and specificity of HbA1c relative to FBG, and compared the overall accuracy by calculating the conditional relative odds ratio (CROR).


RESULTS
Among the 91 subjects, the true- and false-positive odds ratios were 0.43 (95% CI 0.26-0.69) and 0.40 (0.13-1.27) (Fisher's exact test, P < .090), respectively; the CROR was 1.07 (95% CI 0.30-3.75).


CONCLUSIONS
Although the HbA1c test was marginally more specific but less sensitive than the FBG test, at the given cutoff points the accuracies of two tests were equivalent.
Shibata
Kiyoshi
K
Department of Health Promotion and Preventive Medicine, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
Suzuki
Sadao
S
Sato
Juichi
J
Ohsawa
Isao
I
Goto
Shinichi
S
Iritani
Isao
I
Tokudome
Shinkan
S
D000328:Adult; D000368:Aged; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis*; D005189:False Positive Reactions; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D006943:Hyperglycemia / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D012680:Sensitivity and Specificity
D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin