Comparison of fasting plasma glucose and glycated hemoglobin for diagnosing diabetes in a Taiwanese population.
BACKGROUND
The purposes of this study were to examine the impact of using glycated hemoglobin (HbA1c) as a diagnostic criterion for (pre)diabetes and to determine the appropriate HbA1c cutoff value in a Taiwanese population.


METHODS
We used a dataset from the Clinical Informatics Research & Development Center of Taichung Veteran General Hospital. Fasting plasma glucose (FPG) and HbA1c test results were obtained from outpatient laboratory reports produced from January 1, 2011, to April 30, 2012. A total of 4920 blood tests were analyzed. For each potential HbA1c cutoff value, the sensitivity, specificity, positive and negative predictive values, and area under the receiver operator characteristic curve (AUC) were calculated at FPG levels of 100 and 126 mg/dL. Two-sample t- and chi-sqaured tests were used to compare differences in characteristics between individuals matching the definitions of diabetes set by the American Diabetes Association (ADA) in 2009 and 2010.


RESULTS
Among the 4920 study subjects, 580 people had an FPG value < 126 mg/dL and an HbA1c ≥ 6.5%. After the diagnostic criterion of HbA1c percentage was applied, the numbers of patients with normoglycemia and prediabetes decreased, whereas the number of diabetic patients increased. For FPG levels of 100 and 126 mg/dL, the HbA1c cutoff points were 5.95% and 6.35%, respectively.


CONCLUSIONS
More patients were diagnosed with diabetes when HbA1c was added as a diagnostic criterion. HbA1c thresholds of 5.95% and 6.35% were highly specific for prediabetes and diabetes, respectively, in Taiwanese adults.
1 Division of Endocrinology and Metabolism, Department of Internal Medicine, Puli Branch of Taichung Veterans General Hospital , Nantou, Taiwan .
Yun-ju
YJ
Lai
Shih-tan
ST
Lee
Shih-chieh
SC
Kuo
Pesus
P
Chou
D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001774:Blood Chemical Analysis / Q000592:standards; D001786:Blood Glucose / Q000032:analysis*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000175:diagnosis*; D005215:Fasting / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D005951:Glucose Tolerance Test / Q000592:standards; D006442:Glycated Hemoglobin / Q000737:chemistry*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood; D011788:Quality of Life; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013624:Taiwan; D055815:Young Adult
D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human