Introduction Successful treatment response for early syphilis involves resolution of signs and a fourfold decrease in RPR/VDRL or sero-reversion between 3 and 6 months. However, in the HIV-positive population the serological response can be unusual.
Aims To compare serological response after treatment of early syphilis between HIV-positive and negative cohorts.
Methods Retrospective cohort study of 100 HIV positive (HP) and 92 negative (HN) patients with early syphilis at an inner city GUM clinic from 2002 to 2011. Data were collected on demographics, stage of syphilis, treatment and serological response.
Results Both HP and HN cohorts were mainly MSM (72 HN, 96 HP) and Caucasian (HN 76, HP 78). Median age 33 (range 20–63 years) in the HN and 37 (range 19–59 years) in the HP. Stage of syphilis: HN group, 22/92 primary, 26 secondary and 44 early latent (EL). HP group: 26/100 primary, 34 secondary and 39 EL. The HN group were treated with the standard regimen for their stage of disease. 49/100 of the HP group received treatment for neurosyphilis. 25/92 HN and 14/100 HP were lost to follow-up following treatment. Excluding these patients, by 6 months, 18/20 (90%) of the HP group with primary syphilis sero-reverted or had a fourfold decrease in RPR/VDRL compared to 17/17 (100%) of the HN. By 6 months, 51/55 (93%) of the HP group with secondary/EL syphilis had sero-reverted or had a fourfold decrease in RPR/VDRL compared to 41/45 (91%) of the HN. Median CD4 count in the HP group was 380 cells/μl prior to treatment and 518 after treatment. There were 4 reinfections in the HN group and 10 in the HP.
Conclusions There were high rates of serological treatment success for early syphilis in both groups. However, the HP group were less likely to have a successful response by 6 months in primary syphilis. This study also demonstrates the need for strategies to address the large number of patients lost to follow-up.