Optimal HbA1c Level for Screening of Prediabetes and Diabetes in a Multiethnic Singaporean Population

• Published in: Indian journal of clinical biochemistry Vol. 34; no. S1; p. S132
• Main Authors: Lee, J, Lam, L, Yang, K.S
• Format: Journal Article
• Language: English
• Published: Springer 24.05.2022
• Subjects: Glycosylated hemoglobin; Medical screening; Prediabetic state
• ISSN: 0970-1915; 0974-0422

Many organizations including American Diabetes Association (ADA) recommend HbA1c of [greater than or equal to] 6.5% as an appropriate cutoff to diagnose diabetes mellitus. Until recently, in Singapore the use of HbA1c has not been accepted due to apprehensions around the influence of ethnicity, hemoglobinopathies and other disorders that alter red cell turnover. The aim of this study are to evaluate the use of HbA1c for diabetes screening, and to determine the optimal HbA1c cutoff for screening of prediabetes and diabetes in Singapore. We designed a prospective study, whereby subjects were recruited from multiple community health screening events from Mar 2017--Mar 2018. The inclusion criteria include both sexes, age (20-80 years old) and ethnicity (Chinese, Malay or Indian). Laboratory tests performed were HbA1c and fasting plasma glucose (FPG). The exclusion criteria were as follows: those who were pregnant, ever diagnosed with diabetes, those with chronic kidney disease, and those with hemoglobinopathies. 214 subjects were included in the final analysis. In our study, the ADA recommended HbA1c level of 5.7% had a high sensitivity (90.0%) and low specificity (60.3%) when used as a threshold for the identification of prediabetes. In contrast, an HbA1c cutoff of 6.2% predicts prediabetes and diabetes with a sensitivity (75.0%) and specificity (35.4%) and the AUC was 0.884. Our study findings were consistent with the recommendations of the Singapore Ministry of Health March 2013 health screening guidelines for diabetes. Our proposed HbA1c cutoff at 6.2% has similar sensitivity and specificity in screening for prediabetes and diabetes compared to the recommended 6.1%.