Abstract:Objective: Investigation of influencing factors and development of a prediction model for comorbid depressive disorder in patients with postherpetic neuralgia. Methods: A retrospective analysis was conducted on clinical data from 282 patients with postherpetic neuralgia admitted to the Department of Pain Medicine at the First Affiliated Hospital of Fujian Medical University between March 2021 and December 2024. Based on the presence of comorbid depressive disorder, patients were divided into two groups: PHN with comorbid depression (n = 94) and PHN alone (n = 188). Logistic regression analysis was employed to identify influencing factors, followed by the construction of a nomogram prediction model. The performance of the model was comprehensively evaluated. Results: Multivariate logistic regression analysis identified duration of PHN, history of malignant tumor, NRS score, educational attainment, and SSRS score as significant influencing factors for comorbid depressive disorder in PHN. Following internal validation via the bootstrap method, the nomogram achieved an AUC of 0.970 (95% CI: 0.941 - 0.987) for predicting comorbid depression, with a sensitivity of 0.890 and specificity of 0.941, indicating excellent discriminative ability. The Hosmer-Lemeshow test result shows that X2 = 5.293, P = 0.726, and the Brier score is 0.049. The calibration curve indicates that the model has good calibration and prediction consistency. The clinical decision curve analysis demonstrated that the model has good clinical applicability. Conclusion: Duration of PHN, history of malignant tumor, and NRS score were identified as independent risk factors for comorbid depressive disorder in PHN, while educational attainment and SSRS score served as independent protective factors. The nomogram prediction model constructed based on these factors demonstrates robust clinical predictive value.