HbA1c screening for diabetes

HbA(1c) had *poor* *discrimination* ....


Diabetes Care. 2011 Dec;34(12):2597-602. Epub 2011 Sep 27.
Evaluation of nonfasting tests to screen for childhood and adolescent dysglycemia.
Abstract
OBJECTIVE To assess performance of nonfasting tests to screen children for dysglycemia (prediabetes or diabetes). RESEARCH DESIGN AND METHODS This was a cross-sectional study of 254 overweight or obese (BMI ≥85th percentile) children aged 10-17 years. Subjects came for two visits to a clinical research unit. For visit one, they arrived fasting and a 2-h glucose tolerance test and HbA(1c) and fructosamine testing were performed. For visit two, they arrived nonfasting and had a random plasma glucose, a 1-h 50-g nonfasting glucose challenge test (1-h GCT), and urine dipstick performed. The primary end point was dysglycemia (fasting plasma glucose ≥100 mg/dL or a 2-h postglucose ≥140 mg/dL). Test performance was assessed using receiver operating characteristic (ROC) curves and calculations of area under the ROC curve. RESULTS Approximately one-half of children were female, 59% were white, and 30% were black. There were 99 (39%) cases of prediabetes and 3 (1.2%) cases of diabetes. Urine dipstick, HbA(1c) (area under the curve [AUC] 0.54 [95% CI 0.47-0.61]), and fructosamine (AUC 0.55 [0.47-0.63]) displayed poor discrimination for identifying children with dysglycemia. Both random glucose (AUC 0.66 [0.60-0.73]) and 1-h GCT (AUC 0.68 [0.61-0.74]) had better levels of test discrimination than HbA(1c) or fructosamine. CONCLUSIONS HbA(1c) had poor discrimination, which could lead to missed cases of dysglycemia in children. Random glucose or 1-h GCT may potentially be incorporated into clinical practice as initial screening tests for prediabetes or diabetes and for determining which children should undergo further definitive testing.
PMID: 21953800

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