Selection of clinical diagnosic cut point of HbA1Cin Chongming rural areas of Shanghai / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the optimal HbA1Cthreshold to be used for the diagnosis of diabetes mellitus in Chongming rural area,and further to evaluate the optimal HbA1Ccutoff values in different age stratifications and body mass index classifications.Methods Data from 9,981 individuals aged greater than 40 years who participated in a population-based cross-sectional survey in Shanghai,China,were analyzed.A 2 h 75 g oral glucose tolerance test(OGTT)value was used to diagnose diabetes.The performance of HbA1Cwas evaluated against the results of the OGTTs by using receiver operating characteristic(ROC)curve analysis.Results At the optimal HbA1C cutoff point of 6.15%for newly diagnosed diabetes, sensitivity was 69.73%, and specificity was 89.71%.The optimal HbA1Ccutoff points for diabetes were 6.05%in subject with age less than 60 years(sensitivity was 72.88%, and specificity was 90.25%),and 6.25%in subjects with age≥60 years(sensitivity was 70.89%,and specificity was 92.34%).The optimal HbA1Ccutoff points for diabetes were 6.05% in normal-weight(with sensitivity 70.94%,and specificity 89.93%),6.25%in overweight(with sensitivity 70.21%,and specificity 90.32%), and 6.35% in obese population(with sensitivity 72.33%, and specificity 92.75%).Conclusion An HbA1C threshold of 6.15%was highly specific for detecting undiagnosed diabetes.The HbA1Cdiagnosis cutoff point can be affected by age and overweight/obesity status.