English abstract
Background: Type 2 diabetes mellitus is highly prevalent in the rapidly growing Omani population. The American Diabetes Association (ADA) has recommended new criteria for Type 2 diabetes, but the new criteria have been challenged as inadequate. We measured the sensitivity and specificity of the ADA criteria compared with World Health Organization (WHO) criteria for the diagnosis of abnormal glucose intolerance in Omani subjects. Methods: Subjects not known to have diabetes were recruited from the Lipid and Endocrine Clinics at Sultan Qaboos University Hospital between 1999 and 2001. Fasting and 2-hour post-75g oral glucose tolerance test (OGTT) glucose levels were measured according to WHO criteria. Results: 176 subjects were recruited for the study. WHO and the ADA criteria were in agreement for 104 out of 115 normal glucose tolerance (NGT), 4 out of 38 impaired glucose tolerance (IGT), and 14 out of 23 diabetic tolerance glucose (DGT) corresponding to a sensitivity of 90%, 10%, and 61% for NGT, IGT, and DGT, respectively. Compared with WHO criteria, the ADA criteria had 30% sensitivity and 90% specificity overall. Comparing fasting glucose cutoff values for the diagnosis of IGT, a cut-off of 5.9 mmol/L yielded the best diagnostic sensitivity and specificity compared to the 6.1 mmol/L recommended by the ADA criteria as determined by the receiver-operating characteristics (ROC), with an area under the curve of 0.677 vs. 0.387, respectively. Conclusion: The ADA criteria had poor sensitivity in the detection of impaired glucose tolerance in high-risk Omani subjects compared with WHO criteria.
