3.4.2. External Validation
To further verify the diagnostic efficacy of the risk score model, we enrolled 389 patients from three other hospitals from 2012 to 2020 and applied the risk score model for external validation. In the external validation group, when the cutoff point was 2, the sensitivity of the diagnosis of DN reached 0.906, and the specificity was 0.596. When the cutoff point was 4, the specificity of the diagnosis of DN reached 0.936. By drawing the ROC curve, the AUC = 0.855 (