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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: .
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Does a Single A1C > = 6.5 % Accurately identify Type 2 Diabetes/Impaired Glucose Tolerance in African Americans? Context: In 2010, the American Diabetes Association revised its criteria for the diagnosis of diabetes to include A1C ≥ 6.5%; however, this has remained controversial, particularly for African Americans. The objective of this pilot study was to examine the usefulness of a single A1C determination in comparison with a same day 2-hour oral glucose tolerance test to diagnose type 2 diabetes in African Americans. In sum, 195 oral glucose tolerance tests and A1Cs were obtained on the same day from 77 overweight and obese African American women and 6 men over a period of 15 months. A1C ≥ 6.5% was present in 31 of 195 patients, with 15 of these having type 2 diabetes by oral glucose tolerance test, another 12 having impaired glucose tolerance, and 4 having normal glucose tolerance. This gives a sensitivity of 50% and a specificity of 90%, with a positive predictive value of 48% and a negative predictive value of 91%. A1C ≤ 5.6%, proposed by the American Diabetes Association to indicate normal glucose tolerance, was present in only 28 patients, 10 (35.7%) of whom had normal glucose tolerance, whereas 18 (64.3%) had either impaired glucose tolerance (15 patients) or type 2 diabetes (3 patients). Fasting plasma glucose ≥ 126 mg/dL was present in 5 of 29 patients with type 2 diabetes (sensitivity, 17.2%; specificity, 100%).
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First, A1C ≥ 6.5% was a good "rule in" value to identify impaired glucose tolerance and type 2 diabetes (ie, patients at high risk for micro- and macrovascular complications). Second, A1C ≤ 5.6% did not rule out impaired glucose tolerance or type 2 diabetes. Last, fasting plasma glucose ≥ 126 mg/dL detected less than 1 in 5 cases with type 2 diabetes. Final Decision: yes