Abstract: Objective: To investigate the incidence of neurosyphilis in patients with syphilis serofast after standard treatment, and analyze the related factors. Methods:The clinical data of patients with syphilis serofast whom performed lumbar puncture from January 2013 to June 2021 was retrospectively reviewed. Logistic regression model was used to analyze the related factors of neurosyphilis, and the Receiver operating curve (ROC) was used to evaluate the diagnostic value of initial serum TRUST titer for neurosyphilis. Results: 101 patients were collected including 30 neurosyphilis patients (26 males and 4 females) and 71 syphilis patients (25 males and 46 females).  Male sex (OR=9.210，95%CI 2.450-34.620，P=0.001) and initial serum TRUST titer （OR=1.808，95%CI 1.143-2.858，P=0.011）were significantly associated with neurosyphilis. The area under the ROC curve (AUC) was 0.708 (P=0.001), Youden's index 0.407. Conclusion: The Male sex，high level of Serum TRUST titer are the risk factors for neurosyphilis, but the value of initial TRUST titer in the diagnosis of neurosyphilis is low according to the AUC.

Key words: syphilis serofast, neurosyphilis, TRUST titers, related factors, logistic regression