Diabetes Care, Vol 21, Issue 7 1133-1137, Copyright © 1998 by American Diabetes Association
Usefulness of revised fasting plasma glucose criterion and characteristics of the insulin response to an oral glucose load in newly diagnosed Japanese diabetic subjects
Y Tanaka, Y Atsumi, T Asahina, K Hosokawa, K Matsuoka, J Kinoshita, T Onuma and R Kawamori
Department of Medicine, Metabolism and Endocrinology, Juntendo University, Tokyo, Japan.
OBJECTIVE: To examine the usefulness of the revised criterion for fasting
plasma glucose (FPG) in the diagnosis of diabetes recommended by the
American Diabetic Association (ADA) (126 mg/dl, 7 mmol/l), and to
characterize insulin response during the 75-g oral glucose tolerance test
(OGTT) in newly diagnosed Japanese diabetic subjects. RESEARCH DESIGN AND
METHODS: A series of 2,121 Japanese subjects underwent a 75-g OGTT (0-3 h)
and were divided into three groups (normal glucose tolerance [NGT],
impaired glucose tolerance [IGT], and diabetes mellitus [DM] according to
the current World Health Organization criteria. After the cutoff values of
FPG that distinguish NGT and IGT from diabetes were analyzed, the
usefulness of the ADA criterion for FPG was examined by comparing
diagnostic parameters (sensitivity, specificity, and accuracy) with those
for the cutoff value of 140 mg/dl. To assess insulin response, both the
insulinogenic index (IsIx), a marker of early secretion, and the area under
the insulin response curve (AUCins), a marker of total secretion, were
compared between the DM, NGT, and IGT groups. RESULTS: First, the FPG
cutoff value distinguishing NGT from diabetes was 109 mg/dl. An FPG of 126
mg/dl showed a higher sensitivity (0.52 vs. 0.31), the same specificity
(1.00), and a higher accuracy (0.82 vs. 0.74) than an FPG of 140 mg/dl, and
it had a higher specificity (1.00 vs. 0.86) with a slightly lower accuracy
(0.82 vs. 0.85) than an FPG of 109 mg/dl. Second, the FPG cutoff value
differentiating IGT from diabetes was 113 mg/dl. An FPG of 126 mg/dl showed
a higher sensitivity (0.52 vs. 0.31) and accuracy (0.80 vs. 0.74) and a
similar specificity (0.97 vs. 1.00) compared with an FPG of 140 mg/dl, and
it had a higher specificity (0.97 vs. 0.82) with the same accuracy (0.80)
as an FPG of 113 mg/dl. Third, the DM group showed the lowest IsIx among
the three groups at all FPG values. The AUCIns in the DM group increased
along with FPG, reached the maximum level at an FPG of 110 mg/dl, and
declined thereafter. AUCIns was higher in the DM group than in the NGT
group at FPG values > or = 100 mg/dl. CONCLUSIONS: The revised ADA
criterion for FPG of 126 mg/dl may improve diagnostic sensitivity without
loss of specificity in Japanese diabetic subjects when compared with an FPG
criterion of 140 mg/dl. Although early insulin secretion was impaired,
total insulin secretion did not seem to be reduced in newly diagnosed
Japanese diabetic subjects.