Use of GHb (HbA1c) in screening for undiagnosed diabetes in the U.S. population.
OBJECTIVE
To evaluate the use of GHb as a screening test for undiagnosed diabetes (fasting plasma glucose > or =7.0 mmol/l) in a representative sample of the U.S. population.


METHODS
The Third National Health and Nutrition Examination Survey included national samples of non-Hispanic whites, non-Hispanic blacks, and Mexican Americans aged > or =20 years. Of these subjects, 7,832 participated in a morning examination session, of which 1,273 were excluded because of a previous diagnosis of diabetes, missing data, or fasting time of <8 h before examination. Venous blood was obtained to measure fasting plasma glucose and GHb in the remaining 6,559 subjects. Receiver operating characteristic curve analysis was used to examine the sensitivity and specificity of GHb for detecting diabetes at increasing GHb cutoff levels.


RESULTS
GHb demonstrated high sensitivity (83.4%) and specificity (84.4%) for detecting undiagnosed diabetes at a GHb cutoff of 1 SD above the normal mean. Moderate sensitivity (63.2%) and very high specificity (97.4%) were evident at a GHb cutoff of 2 SD above the normal mean. Sensitivity at this level ranged from 58.6% in the non-Hispanic white population to 83.6% in the Mexican-American population; specificity ranged from 93.0% in the nonHispanic black population to 98.3% in the non-Hispanic white population.


CONCLUSIONS
GHb is a highly specific and convenient alternative to fasting plasma glucose for diabetes screening. A GHb value of 2 SD above the normal mean could identify a high proportion of individuals with undiagnosed diabetes who are at risk for developing diabetes complications.
Rohlfing
C L
CL
Department of Child Health, University of Missouri School of Medicine, Columbia 65203, USA. rohlfingc@health.missouri.edu
Little
R R
RR
Wiedmeyer
H M
HM
England
J D
JD
Madsen
R
R
Harris
M I
MI
Flegal
K M
KM
Eberhardt
M S
MS
Goldstein
D E
DE
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D044383:Black People; D001786:Blood Glucose / Q000032:analysis*; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D006442:Glycated Hemoglobin / Q000032:analysis*; D006306:Health Surveys; D006630:Hispanic or Latino; D006801:Humans; D008403:Mass Screening / Q000379:methods; D017058:Mexican Americans; D008875:Middle Aged; D009749:Nutrition Surveys; D012372:ROC Curve; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D014481:United States / Q000453:epidemiology; D044465:White People; D001741:Black or African American
D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin