Ideal glycated hemoglobin cut‐off points for screening diabetes and prediabetes in a Chinese population

Abstract

Aims/IntroductionThe aims of the present study were to evaluate the diagnostic value of fasting plasma glucose, 2‐h postload plasma glucose and glycosylated hemoglobin (HbA1c) measurements in the screening of diabetes and prediabetes, and to determine the cut‐off point of HbA1c in the diagnosis of diabetes and prediabetes in a Chinese population.Materials and MethodsA total of 7,611 individuals aged 40 years or older, who did not have a prior history of diabetes, were randomly selected in the Changchun area. For each participant, a questionnaire was completed, and a physical examination and an oral glucose tolerance test were carried out. The values of fasting plasma glucose, 2‐h postload plasma glucose and HbA1c were compared by area under the receiver operating characteristic curves. The Youden index was used to identify the optimal cut‐off point of HbA1c in the diagnosis of diabetes and prediabetes.ResultsThe prevalence of newly diagnosed diabetes and prediabetes was 12.71% and 29.39%, respectively. In participants with newly diagnosed diabetes, the area under the receiver operating characteristic curve was 0.8368 for fasting plasma glucose, 0.9330 for 2‐h postload plasma glucose and 0.8064 for HbA1c; whereas for prediabetes, these values were 0.8022, 0.9288 and 0.6895, respectively. In addition, an HbA1c threshold of 6.3% showed the highest Youden index (0.4799) for detecting diabetes; furthermore, an HbA1c threshold of 5.8% showed the highest Youden index (0.2866) for detecting prediabetes.ConclusionsHbA1c ≥6.3% (45 mmol/mol) and between 5.8% and 6.2% (40–44 mmol/mol) were the optimal cut‐off values for the diagnosis of diabetes and prediabetes, respectively, in a Chinese population.

Screening for diabetes in dental settings

“…This should then result in a significant reduction in the burden of testing on both patients and testing facility staff and resources. On the other hand, another recent study evaluated the diagnostic value of HbA1c measurements in screening of diabetes and prediabetes, and determine the cut-off point of HbA1c in a Chinese population (Liu et al, 2016). The results suggested an optimal HbA1c cut-off point of 6.3% in screening diabetes, consistent with a previous study, the authors also proposed an ideal HbA1c cut-off point of 5.8% in screening prediabetes.…”

Sex and age discrepancy of HbA1c and fetal hemoglobin determined by HPLC in a large Chinese Han population

“…accuracy of HbA1c measurements as a criterion for diabetes diagnosis had not been completely evaluated and unanimously accepted. [30][31][32] The recommended cut-off value of HbA1c ≥6.5% was reported to have a different sensitivity of risk compared with the oral glucose tolerance test among Chinese individuals. [33][34][35] Several other studies [36][37][38][39][40][41] questioned the single HbA1c cut-off value for a diabetes diagnosis because of the absence of agespecific criteria.…”

Re‐examining the sensitivity of HbA1c to screen for diabetes mellitus

“…We also found that using HbA1c and a cut‐off of 6.5% as a screening test for DM had a lower sensitivity (83.6%) and higher specificity (83.2%; Table ) in Chinese adults than in Malays and Indians (sensitivity 86.7–87.5%, specificity 77.6–80.7%), similar to results published by Sabanayagam et al These sensitivity and specificity results are similar to those reported by Wang et al who found that HbA1c at a cut‐off of 6.5% had a high sensitivity (80.6%) and specificity (86.9%) for detecting diabetic retinopathy. However, many studies on Chinese subjects recommended lower cut‐offs values, such as 5.6%, 5.8%, 6.2%, and 6.3%, for diagnosing DM, because these studies did not have repeat testing to confirm the diagnosis of DM.…”