Figure 3. ROC curve analysis. A: Sensitivity and specificity of serum cortisol (S cortisol) to discriminate controls and no retinopathy (NoDR) cases using receiver operating characteristics (ROC) curve analysis. Discrimination between controls and NoDR cases with 80.00% sensitivity (95% confidence interval (CI)=51.9-95.4) and 73.33% specificity (95% CI=44.9-92.0) at cut off value of >9.3 microgram per deciliter (µg/dl). B: Sensitivity and specificity of serum cortisol to discriminate controls and non-proliferative diabetic retinopathy (NPDR) cases using ROC curve analysis. Discrimination between controls and NPDR cases with 81.25% sensitivity (95% CI=54.3-95.7) and 73.33% specificity (95% CI=44.9-92.0) at cut off value of >9.5μg/dl. C: Sensitivity and specificity of serum cortisol to discriminate controls and proliferative diabetic retinopathy (PDR) cases using ROC curve analysis. Discrimination between controls and PDR cases with 86.67% sensitivity (95% CI=59.5-98.0) and 80.00% specificity (95% CI=51.9-95.4) at cut off value of >10.2 μg/dl.