Characteristics of study participantsa

CharacteristicValues for:P value
Training data set (n = 191)Validation data set (n = 380)
No. (%) of male participants185 (96.9)373 (98.2)NS
No. (%) of HIV-infected participants158 (82.7)297 (78.2)NS
Median (IQR) age (yr)37 (32–43)41 (32–48)0.001
Median (IQR) 1/serum RPR titer64 (32–256)64 (16–128)NS
No. (%) of participants:
    With early syphilisb133 (69.6)284 (74.7)NS
    Treated for uncomplicated syphilis before lumbar puncture69 (36.1)203 (53.4)<0.001
    With reactive CSF-VDRL60 (31.4)47 (12.4)<0.001
    In whom T. pallidum was detected in CSF by RT-PCR45 (23.6)41 (10.8)<0.001
Median (IQR) no. of:
    CSF WBCs9 (2–33)5 (2–14)0.02
    CSF RBCs1 (0–9)1 (0–14)NS
No. (%) of participants with new vision or hearing loss40 (22.0)c95 (25.0)NS
No. (%) of participants treated for neurosyphilis105 (55.0)120 (31.6)<0.001
  • a CSF, cerebrospinal fluid; RBCs, red blood cells; RPR, rapid plasma reagin; RT-PCR, reverse transcriptase PCR; WBCs, white blood cells; IQR, interquartile range; CSF-VDRL, CSF Venereal Disease Research Laboratory test; NS, not significant.

  • b Early syphilis includes the primary, secondary, and early latent stages.

  • c Data are for 182 patients.