Diabetes Care, Vol 21, Issue 11 1856-1860, Copyright © 1998 by American Diabetes Association
Fasting plasma glucose in screening for diabetes in the Taiwanese population
CJ Chang, JS Wu, FH Lu, HL Lee, YC Yang and MJ Wen
Department of Family Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China. jins@mail.ncku.edu.tw
OBJECTIVE: To reveal the relationship between fasting and 2-h postload
plasma glucose and to examine the appropriate fasting glucose cutoff as the
primary screening test for diabetes. RESEARCH DESIGN AND METHODS: We
recruited 5,303 subjects from preventive services of the National Cheng
Kung University Hospital. Exclusion criteria were age <20 years,
pregnancy, known diabetes, and a history of recent surgery, trauma, or
illness. All subjects received the 75-g oral glucose tolerance test. The
relationship between fasting and 2-h glucose was examined. Sensitivities,
specificities, efficiency, and predictive values were assessed at different
cutoffs of fasting glucose for prediction of diabetes. RESULTS: The best
fit model for the relationship between fasting and 2-h glucose was fasting
glucose = 4.914-0.060 x (2-h glucose) + 0.0144 x (2-h glucose)2. From this
model, the fasting glucose was 6.0 mmol/l when 2-h glucose was 11.1 mmol/l.
A fasting glucose with 6.25 mmol/l gave the same diabetes prevalence as the
World Health Organization 2-h glucose criterion. When 7.8 mmol/l was the
fasting glucose cutoff, the sensitivity was 28.5%. Lowering the cutoff from
7.8 to 7.0 mmol/l increased the sensitivity by 11.2% and slightly reduced
the specificity and positive predictive value. If the cutoffs were 6.25 and
6.0 mmol/l, the sensitivity increased and the specificity and the positive
predictive value decreased accordingly. CONCLUSIONS: Our results suggest
that fasting glucose as a screening criterion for diabetes could be revised
downward to 7.0 mmol/l, because the slight reduction of positive predictive
value was more than balanced by an apparent increase of sensitivity and
insignificant change of specificity.