Population Prevalence and Correlates of Syphilis in Rural, Southwestern Uganda.

Abstract

Background: The global incidence of syphilis has increased in recent years. Understanding syphilis epidemiology will inform screening and treatment programs. However, such data are lacking in many communities. We outline a population-based syphilis screening program in a rural community in southwestern Uganda to describe the population prevalence of syphilis.

Methods: In June 2019 we conducted a cross-sectional, population-based study of adults >18 years of age. Two-stage syphilis testing was completed with Treponema pallidum hemagglutination (TPHA) rapid immunochromatographic testing, confirmed by rapid plasma reagin (RPR) in those with positive TPHA (syphilis seroprevalence). We calculate inverse probability of treatment (IPT) weights using logistic regression to estimate the population prevalence of positive TPHA. We included covariates with a univariable α = .10 in multivariable logistic regression models, stratified by sex, to estimate correlates of syphilis seroprevalence.

Results: Among 749 participants who participated in this population-based study, 724 (97%) completed syphilis screening. The median age was 42.9 years (standard deviation, 15.6 years) and 456 of 724 (63%) were women. Based on the IPT-weighted adjusted model, the syphilis population seroprevalence was 10.6% (95% confidence interval, 8.4%-13.4%). Among the 62 of 79 (78%) participants who completed RPR testing, all had titers ≤1:4. Syphilis seroprevalence was associated with less education, human immunodeficiency virus (HIV) infection, and ≥2 sexual partners in the prior month among women and with HIV among men.

Conclusions: We describe a high prevalence of current or former syphilis (10.6%) in a population-based study in rural Uganda. Syphilis screening and surveillance programs in this region require expansion to capture populations not routinely in care.