Diagnostic accuracy of HbA1c in diabetes between Eastern and Western.

Background In 2010, the American Diabetes Association recommended the use of HbA1c as a diagnostic criterion for diabetes. However, HbA1c is not an accepted diagnostic tool for diabetes in Eastern Asia, because genetic differences compromise the standardization of the diagnostic cut-off point. Objectives This study evaluated differences in the use of HbA1c for diagnosing diabetes in Eastern and Western populations and investigated whether HbA1c cut-off point of 6 center dot 5% is diagnostic of diabetes in patients from Eastern Asia. Methods Literature was obtained from MEDLINE, EMBASE and Cochrane databases. The pooled sensitivity and specificity of each HbA1c cut-off point were extracted and compared between Western and Eastern populations. Differences in the cut-off point for diagnosing diabetes in each region were compared by examining differences in the area under summary receiver operating characteristic (SROC) curves. Results Twelve publications from Eastern countries (n=59735) and 13 from Western countries (n=22954) were included in the analysis. Areas under SROC curves in the Eastern and Western groups were 0 center dot 9331 and 0 center dot 9120, respectively (P=0 center dot 98). The cut-off point of the highest Youden index was 6 center dot 0%. At the HbA1c cut-off point of 6 center dot 5%, the pooled sensitivity and specificity were 58 center dot 7% and 98 center dot 4% for Eastern countries and 65 center dot 5% and 98 center dot 1% for Western countries, respectively. Conclusions HbA1c exhibits the same diagnostic value for diabetes in Eastern and Western populations. In both populations, HbA1c levels >6 center dot 0% identify the population at high risk of diabetes, and HbA1c>6 center dot 5% is diagnostic of clinically established diabetes.