Author(s): Bennett CM, Guo M, Dharmage SC
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Abstract AIM: To assess the validity of glycated haemoglobin A(1c) (HbA(1c)) as a screening tool for early detection of Type 2 diabetes. METHODS: Systematic review of primary cross-sectional studies of the accuracy of HbA(1c) for the detection of Type 2 diabetes using the oral glucose tolerance test as the reference standard and fasting plasma glucose as a comparison. RESULTS Nine studies met the inclusion criteria. At certain cut-off points, HbA(1c) has slightly lower sensitivity than fasting plasma glucose (FPG) in detecting diabetes, but slightly higher specificity. For HbA(1c) at a Diabetes Control and Complications Trial and UK Prospective Diabetes Study comparable cut-off point of > or = 6.1\%, the sensitivity ranged from 78 to 81\% and specificity 79 to 84\%. For FPG at a cut-off point of > or = 6.1 mmol/l, the sensitivity ranged from 48 to 64\% and specificity from 94 to 98\%. Both HbA(1c) and FPG have low sensitivity for the detection of impaired glucose tolerance (around 50\%). CONCLUSIONS HbA(1c) and FPG are equally effective screening tools for the detection of Type 2 diabetes. The HbA(1c) cut-off point of > 6.1\% was the recommended optimum cut-off point for HbA(1c) in most reviewed studies; however, there is an argument for population-specific cut-off points as optimum cut-offs vary by ethnic group, age, gender and population prevalence of diabetes. Previous studies have demonstrated that HbA(1c) has less intra-individual variation and better predicts both micro- and macrovascular complications. Although the current cost of HbA(1c) is higher than FPG, the additional benefits in predicting costly preventable clinical complications may make this a cost-effective choice.
This article was published in Diabet Med
and referenced in Journal of Diabetes & Metabolism