Introduction

Coinfection of human immunodeficiency virus and syphilis pose a global health challenge and present diagnostic complexities. People with human immunodeficiency virus experience a higher rate of syphilis serological failure than patients without human immunodeficiency virus.

Objectives

To assess laboratory characteristics and the course of syphilis treatment in a group of Polish patients with human immunodeficiency virus-1.

Material and methods

Demographic and laboratory data of patients with human immunodeficiency virus-1 and syphilis admitted to one of the infectious diseases departments in Poland in the years 2008–2023 were collected retrospectively. The c2 or Fisher’s exact tests were used to assess differences in categorical variables. Logistic regression analyses evaluated factors related to serological treatment failure in syphilis.

Results

There were n = 59 syphilis infections among n = 43 patients. All patients were male, aged from 21 to 60, all were taking antiretroviral treatment (ART) and had undetectable viral load. Among all syphilis infections, n = 34 were primary, n = 3 were late, and n = 22 were syphilis of unknown duration. The mean lymphocyte T CD4 count was 621 cells/μl. In n = 11 (18.64%) infections there was no 4-fold decline in VDRL in the course of 12 months after treatment. Univariate and multivariate analysis showed VDRL titer < 1 : 32 to be associated with higher odds of serological failure.

Conclusions

People with HIV regardless of their undetectable HIV-1 viral load and their lymphocyte T CD4 count are at risk of syphilis serological failure. Those with VDRL titer < 32 might be at higher risk of serological treatment failure. Regular screening for syphilis and monitoring of serological response to syphilis treatment is recommended for people with HIV-1.