Objective: Diabetic retinopathy (DR) is an important cause of blindness in type 2 diabetic patients. When it occurs, it affects
the patient’s quality of life including their physical activity, emotion, mentality, and social interactions. Therefore, the objectives of this research were to study the relationship between glycaemic control and DR and the relationship between DR and other factors. We also aim to find the optimal cut-off point to screen diabetic retinopathy using glycated haemoglobin (HbA1c) levels.
Material and Method: We performed a case-control study. One hundred patients were divided into two groups (50 patients for DR group and 50 patients for non-DR group). Their HbA1c, weight, height, blood pressure, and lipid profiles were
retrospectively reviewed by Electronic Medical Record (EMR). The data was analysed using both Chi-square test and logistic
regression with two-tailed hypothesis.
Results: The research revealed that uncontrolled glycaemic in type 2 diabetic patients was significantly related to DR (Adjusted odds ratio 8.89, 95% CI = 2.3-18.00, p-value <0.001). In addition, it occurred more commonly in males (Adjusted odds ratio 6.41, 95% CI = 3.02-26.25, p-value <0.001). A cut-off level of HbA1c for screening DR is 7.25% (sensitivity 84%,
specificity 66%, positive predictive value = 71.2%, negative predictive value = 80.5%).
Conclusion: HbA1c level and male gender are strongly related to DR (p<0.001) and the optimal cut-off level for DR screening
is 7.25% in type 2 diabetic patients that were treated in HRH Princess Maha Chakri Sirindhorn Medical Center.

Keywords: Glycaemic control, Microvascular complication, Diabetic retinopathy, HbA1c, Hypertension, Dyslipidemia