FASTING PLASMA-GLUCOSE IN SCREENING FOR DIABETES IN THE TAIWANESE POPULATION

OBJECTIVE - To reveal the relationship between fasting and 2-h postloa d plasma glucose and to examine the appropriate fasting glucose cutoff as the primary screening test for diabetes. RESEARCH DESIGN AND METHO DS - We recruited 5,303 subjects from preventive services of the Natio nal Cheng Kung University Hospital. Exclusion criteria were age <20 ye ars, pregnancy, known diabetes, and a history of recent surgery, traum a, or illness. All subjects received the 75-g oral glucose tolerance t est. The relationship between fasting and 2-h glucose was examined. Se nsitivities, specificities, efficiency, and predictive values were ass essed at different cutoffs of fasting glucose for prediction of diabet es. 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 Organiza tion 2-h glucose criterion. When 7.8 mmol/l was the fasting glucose cu toff, the sensitivity was 28.5%. Lowering the cutoff from 7.8 to 7.0 m mol/l increased the sensitivity by 11.2% and slightly reduced the spec ificity and positive predictive value. If the cutoffs were 6.25 and 6. 0 mmol/l, the sensitivity increased and the specificity and the positi ve predictive value decreased accordingly CONCLUSIONS - Our results su ggest that fasting glucose as a screening criterion for diabetes could be revised downward to 7.0 mmol/l, because the slight reduction of po sitive predictive value was more than balanced by an apparent increase of sensitivity and insignificant change of specificity.