Prevalence of syphilis among people living with HIV who attend a large urban antiretroviral therapy clinic in Panama: a cross-sectional epidemiological study.

ABSTRACT

Background: Syphilis is a serious global public health challenge. Despite prior progress in syphilis control, incidence has been increasing in recent years. Syphilis is a common coinfection among people living with HIV (PLHIV). In Panama, few data describe syphilis prevalence among PLHIV. We describe syphilis antibody and high-titer (⩾18) active syphilis prevalence and associated factors among individuals who attended an antiretroviral clinic. Methods: A cross-sectional study was undertaken during February-March 2022 and September-October 2022 for adults (⩾18 year) assigned male and female at birth, respectively. Participants provided peripheral blood samples and self-administered a questionnaire. Samples were screened using immunochromatography; antibody-positive samples were tested using rapid plasma regain to 1512 dilutions. Logistic regression was used to identify factors associated with syphilis antibody and high-titer active syphilis. Results: In all, 378 participants gave blood samples; 377 individuals participated in the questionnaire (216 self-reported male sex [males], 158 female [females], and three intersex individuals). Median age was 36 years (interquartile range 28-45 years). Overall, syphilis antibody prevalence was 32.3% (122/378) (males, 50.7% [108/2013]; females, 5.7% [9/158]; intersex individuals, 100.0% (3/3)], p < 0.01. High-titer active syphilis was found among 24.6% (n = 30) of samples with positive antibody test (males 27.8% [n = 30], females 0.0% [0/9], intersex individuals 0.0% [0/3]). Antibody positivity was associated in the multivariable model with males (50.7%, AOR = 24.6, 95%CI 1.57-384.53). High-titer active syphilis was associated with younger participant age (18-30 years, 13.2%, OR = 4.82, 95%CI 1.17-19.83); 31-40 years, 7.8%, OR = 4.24, 95%CI 1.04-17.21 versus 3.2% >40 years), homosexual identity (16.0% OR = 34.2, 95%CI 4.50-259.27 versus 0.6% among heterosexual identity); in the multivariable model, associated with sexual identity (bisexual 19.1%, AOR = 10.89, 95%CI 1.00-119.06) compared to heterosexual identity (0.6%) and weakly associated with concurrency (⩾1 ongoing sexual relationships, 15.9%, AOR = 3.09, 95%CI 0.94-10.14). Conclusion: This study found very high prevalence of syphilis antibodies and high-titer syphilis among PLHIV in Panama. Those most affected are males, younger in age, those who practice concurrent sexual relationships, and those who reported homosexual and bisexual identity. Targeted interventions should include repetitive testing and treatment, especially among individuals who may be at increased infection risk.

Prevalence of syphilis among people living with HIV who attend a large antiretroviral therapy clinic, Panama, 2022 Syphilis is a significant health challenge worldwide. On a global scale, yearly syphilis incidence is increasing, including in Panama. However, there are no current data to explain syphilis prevalence and who is most affected among people living with HIV in Panama. In order to understand syphilis in Panama and create targeted interventions among specific groups of people, it is important to describe how many people are infected, and who is most affected by this infection. Therefore, we conducted a study among 378 people living with HIV at a treatment clinic in Panama City, Panama. Blood samples and demographic data were collected. In all, syphilis antibodies were found in 32.3% of individuals (50.7% of those who self-report as males, 5.7% as females, and 100% of those who self-report as intersex. Of those with positive antibody tests, 24.6% of individuals also had active syphilis. Only individuals who identify as male had active syphilis. Our findings show high syphilis prevalence among people with HIV in Panama City, particularly among males, those who are younger, those who report sexual identity as homosexual or bisexual, and those with ongoing sexual relationships with more than one individual. Targeted interventions are needed among people living with HIV, especially among the groups most affected. These interventions could include testing more often for syphilis and providing timely treatment, especially among individuals who may be at increased risk of infection.