Glycaemic and haemoglobin A1c thresholds for detecting diabetic retinopathy: the fifth Korea National Health and Nutrition Examination Survey (2011).
OBJECTIVE
Few representative population-based data are available regarding glycaemic and HbA1c thresholds for detecting diabetic retinopathy (DR) in Asia. We investigated the association between DR and fasting plasma glucose (FPG) and HbA1c levels among Korean adults.


METHODS
Using data from the Korea National Health and Nutrition Examination Survey (2011), a total of 5212 adults (≥19 years old) were analysed. When participants had diabetes mellitus and/or a suspicion of DR in two-field nonmydriatic fundus photography, seven standard photographs were obtained after pupil dilatation (75.9% of men, 75.0% of women among the subjects). DR was defined as the presence of ≥1 retinal microaneurysms or blot haemorrhages with or without more severe lesions. Receiver operating characteristic (ROC) curves were used to determine the optimal cut-off value for HbA1c or FPG.


RESULTS
The overall glycaemic thresholds for DR were 6.3mmol/l for FPG and 6.2% (44mmol/mol) for HbA1c. The optimal thresholds did not differ by age group. The sensitivities and specificities were 82.6% and 91.2% for FPG and 93.9% and 89.7% for HbA1c, respectively. The diagnostic discrimination was better for HbA1c than FPG for DR-area under curve: 0.908 for FPG and 0.953 for HbA1c (p=0.007). After being controlled for other covariates, the odds ratio for the risk of DR increased significantly in a consistent way from 6.2% (44mmol/mol) for HbA1c and 6.3mmol/l for FPG.


CONCLUSIONS
According to these nationally representative data, the current diabetes diagnostic values for FPG and HbA1c based on DR may be lower for the Korean population.
Department of Preventive Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA.
Yong-Moon
YM
Park
Division of Endocrinology and Metabolism, Department of Internal Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Seung-Hyun
SH
Ko
Division of Endocrinology and Metabolism, Department of Internal Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Jung-Min
JM
Lee
Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Republic of Korea.
Dae-Jung
DJ
Kim
Department of Internal Medicine, Inje University College of Medicine, Busan, Republic of Korea.
Dong-Joon
DJ
Kim
Department of Biostatistics, The Catholic University of Korea, Seoul, Republic of Korea.
Kyungdo
K
Han
Division of Epidemiology, The Ohio State University College of Public Health, Columbus, OH, USA.
Julie K
JK
Bower
Division of Endocrinology and Metabolism, Department of Internal Medicine, The Catholic University of Korea, Seoul, Republic of Korea. Electronic address: ybahn@catholic.ac.kr.
Yu-Bae
YB
Ahn
D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D003920:Diabetes Mellitus / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000453:epidemiology / Q000378:metabolism; D005215:Fasting / Q000097:blood; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D012372:ROC Curve; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012680:Sensitivity and Specificity
D001786:Blood Glucose; D006442:Glycated Hemoglobin
Diabetic retinopathy (DR); Diagnosis; Fasting plasma glucose (FPG); Haemoglobin A1c (HbA1c)