Relationship of glycosylated hemoglobin to oral glucose tolerance. Implications for diabetes screening.
The oral glucose tolerance test (OGTT) for diagnosis of diabetes is inconvenient and requires a great deal of patient cooperation. Glycosylated hemoglobin (GHb), an index of long-term glycemic control, could offer several practical advantages over the OGTT for diabetes screening. We evaluated GHb as a screen for diabetes in 381 adults from a population with a high prevalence of non-insulin-dependent diabetes (Pima Indians). All individuals underwent a standard OGTT (75 g) and were separated into one of three groups: normal (N), impaired glucose tolerance (IGT), or diabetes mellitus (D) based on World Health Organization criteria. HbA1c, a GHb, was measured by highly precise high-performance liquid chromatography (interassay C.V. less than 4%). The normal range for HbA1c was 4.07-6.03% based on the 95% confidence interval for a nondiabetic, mostly Caucasian population. Compared with OGTT, HbA1c was highly specific (91%); an elevated HbA1c usually indicated D or IGT (sensitivity = 85 and 30%, respectively). A normal HbA1c did not, however, exclude a diagnosis of D or IGT. Based on previous epidemiological studies relating plasma glucose to chronic diabetic complications, GHb as measured in this study would properly identify the vast majority of subjects at risk. Long-term studies are necessary to determine the actual risk of complications in individuals with persistently normal HbA1c and D or IGT (based on OGTT).
Little
R R
RR
Department of Pathology, University of Missouri School of Medicine, Columbia 65212.
England
J D
JD
Wiedmeyer
H M
HM
McKenzie
E M
EM
Pettitt
D J
DJ
Knowler
W C
WC
Goldstein
D E
DE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002851:Chromatography, High Pressure Liquid; D003920:Diabetes Mellitus / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007198:Indians, North American; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D012307:Risk Factors
D006442:Glycated Hemoglobin