Prevalence of serologic markers of transfusion and sexually transmitted infections and their correlation with clinical features in a large cohort of Brazilian patients with sickle cell disease.

BACKGROUND: Patients with sickle cell disease (SCD) often require red blood cell (RBC) transfusion for clinical complications, so may be exposed to transfusion-transmitted infections (TTIs). The prevalence of markers for human immunodeficiency virus (HIV), hepatitis C virus (HCV) and B (HBV), human T-cell lymphotropic virus (HTLV-1/2), Chagas disease, and syphilis in an SCD cohort in Brazil were studied. STUDY DESIGN AND METHODS: Clinical history, interview data, blood samples, and medical chart review data were collected during cohort enrollment from November 2013 to May 2015. Serologic markers of infection were assessed. Standard measures of statistical association were calculated, and multivariable models were developed for the most prevalent infections to identify associated factors. RESULTS: Infection markers were evident in 5.2% (144/2779) of the enrolled cohort. Anti-HCV was detected in 69 (2.5%), syphilis antibodies in 34 (1.2%), anti-HTLV-1/2 in 17 (0.6%), HBV surface antigen in 13 (0.5%), Chagas disease antibodies in 13 (0.5%), and anti-HIV in 8 (0.3%) of participants. Factors associated with increased odds of being anti-HCV reactive were older age, illegal drug use, increasing number of RBCs, more than three pain crises in the previous year, and geographic location. Syphilis was associated with older age, females, and smoking history. CONCLUSION: HCV infection was more common in older patients who may have received RBCs before testing was performed on donations, suggesting possible historic transfusion transmission. The cohort showed decreasing rates of infections and a reduction in transfusion transmission markers in younger patients compared to historical literature except for syphilis, indicating contemporary reduced risk of TTI.

Ocular Syphilis and Human Immunodeficiency Virus Coinfection Among Syphilis Patients in North Carolina, 2014-2016.

BACKGROUND: Ocular syphilis (OS) has been associated with human immunodeficiency virus (HIV) coinfection previously. We compared demographic and clinical characteristics of syphilis patients with and without HIV to identify risk factors for developing OS. METHODS: We reviewed all syphilis cases (early and late) reported to the North Carolina Division of Public Health during 2014 to 2016 and categorized HIV status (positive, negative, unknown) and OS status based on report of ocular symptoms with no other defined etiology. We estimated prevalence ratios (PR) and 95% confidence intervals (CI) for OS by HIV status. Among syphilis patients with HIV, we compared viral loads and CD4 cell counts by OS status. We compared symptom resolution by HIV status for a subset of OS patients. RESULTS: Among 7123 confirmed syphilis cases, 2846 (39.9%) were living with HIV, 109 (1.5%) had OS, and 59 (0.8%) had both. Ocular syphilis was more prevalent in syphilis patients with HIV compared to HIV-negative/unknown-status patients (PR, 1.8; 95% CI, 1.2-2.6). Compared with other patients with HIV, the prevalence of OS was higher in patients with viral loads greater than 200 copies/mL (1.7; 1.0-2.8) and in patients with a CD4 count of 200 cells/mL or less (PR, 2.3; 95% CI, 1.3-4.2). Among 11 patients with severe OS, 9 (81.8%) were HIV-positive. Among 39 interviewed OS patients, OS symptom resolution was similar for HIV-positive (70.0%) and HIV-negative/unknown-status (68.4%) patients. CONCLUSIONS: Syphilis patients with HIV were nearly twice as likely to report OS symptoms as were patients without documented HIV. Human immunodeficiency virus-related immunodeficiency possibly increases the risk of OS development in co-infected patients.

High HIV incidence in men who have sex with men following an early syphilis diagnosis: is there room for pre-exposure prophylaxis as a prevention strategy?

OBJECTIVES: HIV pre-exposure prophylaxis (PrEP) is becoming a pivotal strategy for HIV prevention. Understanding the impact of risk factors for HIV transmission to identify those at highest risk would favour the implementation of PrEP, currently limited by costs. In this service evaluation, we estimated the incidence of bacterial STIs in men who have sex with men (MSM) diagnosed with early syphilis attending a London sexual health clinic according to their HIV status. In addition, we estimated the incidence of HIV infection in HIV-negative MSM, following a diagnosis of early syphilis. METHODS: We undertook a retrospective case note review of all MSM patients diagnosed with early syphilis between January and June 2014. A number of sexual health screens and diagnoses of chlamydia, gonorrhoea and HIV were prospectively analysed following the syphilis diagnosis. RESULTS: 206 MSM were diagnosed with early syphilis. 110 (53%) were HIV-negative at baseline, 96 (47%) were HIV-positive. Only age (37 vs 32 years, p=0.0005) was significantly different according to HIV status of MSM at baseline. In HIV-negative versus HIV-positive MSM, incidence of rectal chlamydia infection at follow-up was 27 cases vs 50/100 person-years of follow-up (PYFU) (p=0.0039), 33 vs 66/100 PYFU (p=0.0044) for rectal gonorrhoea and 10 vs 26/100 PYFU (p=0.0044) for syphilis reinfection, respectively. Total follow-up for 110 HIV-negative MSM was 144 person-years. HIV incidence was 8.3/100 PYFU (CI 4.2 to 14). CONCLUSIONS: A diagnosis of early syphilis carries a high risk of consequent HIV seroconversion and should warrant prioritised access to prevention measures such as PrEP and regular STI screening to prevent HIV transmission.

The impact of combined antiretroviral therapy on biologic false-positive rapid plasma reagin serologies in a longitudinal cohort of HIV-infected persons.

BACKGROUND: Our objective was to determine the impact of combination antiretroviral therapy (cART) and the degree of immunosuppression on biologic false-positive (BFP) rapid plasma reagin (RPR) tests among persons infected with human immunodeficiency virus (HIV). METHODS: This was a nested retrospective study of HIV-infected patients enrolled in the Johns Hopkins HIV Clinical Cohort. BFP RPR was defined as a reactive RPR and a nonreactive fluorescent treponemal antibody-absorption (FTA-ABS) test. Patients with BFP tests were compared to 2 control groups: HIV-infected patients (1) with active syphilis (reactive RPR and FTA-ABS) and (2) without current syphilis (nonreactive RPR). A persistent BFP test was defined by having at least 2 visits with consistent BFP at all visits. RESULTS: Of 711 patients with HIV, 96 (13.5%) had BFP tests and 342 (48.1%) had syphilis. Twenty-two of 96 (23%) had persistent BFP tests. cART use was associated with decreased odds of BFP tests compared to having syphilis (adjusted odds ratio [AOR], 0.31; 95% CI, .15-.63) and those with nonreactive RPR (AOR, 0.42; 95% CI, .22-.81). cART use was also associated with decreased odds of BFP persistence (AOR, 0.07; 95% CI, .01-.33). Neither CD4 count nor HIV RNA was significantly associated with BFP test results. Lower RPR titers, younger age, and injection drug use were associated with increased odds of BFP. CONCLUSIONS: The use of cART appears to decrease the odds of BFP RPR tests. This finding suggests that nontreponemal titer fluctuations in persons with HIV may reflect the influence of factors unrelated to syphilis disease activity.

Syphilis treatment response among HIV-discordant couples in Zambia and Rwanda.

BACKGROUND: Syphilis continues to be a common sexually transmitted infection, despite the availability of inexpensive and effective treatment. Infection in human immunodeficiency virus (HIV)-discordant couples is important because syphilis increases the risk of HIV acquisition. Current US treatment guidelines recommend 1 dose of benzathine penicillin for early syphilis, irrespective of HIV status, but data from coinfected patients are limited. METHODS: Retrospective analysis of 1321 individuals in 2 African HIV-discordant couple cohorts was performed. Cox proportional hazards analysis and multivariable modeling were used to assess predictors of serologic response to treatment at 180 days and 400 days. Modeling was performed for all episodes of positive rapid plasma reagin (RPR) test results and on a subset with higher RPR titers (≥1:4). RESULTS: A total of 1810 episodes of syphilis among 1321 individuals were treated with penicillin between 2002 and 2008. Although a positive RPR was more common in the HIV-infected partners, HIV infection did not impact the likelihood of serologic response to therapy (odds ratio [OR], 1.001; P = .995). By 400 days, 67% had responded to therapy, 27% were serofast, and 6.5% had documented reinfection. Prevalent infections were more likely to remain serofast than incident infections (33% vs 20% at 400 days). CONCLUSIONS: In 2 HIV-serodiscordant couple cohorts in Africa, incident syphilis had a very good likelihood of response to penicillin therapy, irrespective of HIV infection. This supports current Centers for Disease Control and Prevention treatment guidelines. A high proportion of prevalent RPR-positive infections remain serofast despite treatment.

Analysis of risk factors for late presentation in a cohort of HIV-infected patients in Dresden: positive serology for syphilis in MSM is a determinant for earlier HIV diagnosis.

PURPOSE: Late HIV presentation is still a health concern, even in industrialised countries. Data concerning this problem in Eastern Germany are scarce. We investigated associated factors in a cohort of HIV-infected patients in Dresden, Germany, including syphilis serology as a proxy for sexual risk behaviour. METHODS: A retrospective cohort study on 348 patients presenting for the first time in our treatment centre from 1986 to 2010 was undertaken. Risk factors of late (CD4 cells <350/µl) and very late (CD4 cells <200/µl) presentation either to care or to diagnosis were identified by means of logistic regression analyses. RESULTS: Of 348 classifiable patients, 54 % were late and 33.9 % were very late presenters to care. In a subgroup of 260 patients with recent HIV diagnosis, 50.4 % were late and 31.2 % were very late presenters to diagnosis. Age >24 years was a significant independent factor associated with late or very late presentation, but not male gender, originating from high-prevalence countries (HPC) or years of presentation. Being MSM alone was not associated with early or late HIV presentation, but MSM with positive TPHA or TPPA showed a lower risk of late presentation, predominantly in those presenting late to diagnosis [odds ratio (OR) 0.42, p = 0.048]. CONCLUSIONS: A positive syphilis screening test seems to be a determinant for lower risk of late presentation to HIV care and diagnosis in MSM. The presence and awareness of sexually transmitted infections (STIs) such as syphilis may lead to earlier utilisation of HIV health care and, thus, promote earlier HIV diagnosis. HIV prevention strategies should focus more on STIs and not only on HIV.

Osteitis in the dens of axis caused by Treponema pallidum.

BACKGROUND: Syphilis has been referred to as "the great imitator" due to its ability to imitate other diseases. Untreated syphilis becomes a systemic infection that can involve almost every organ systems. Treponema pallidum has a high affinity for bone tissue, but osteitis has mainly been described in late stages of the disease. Vertebral involvement is rare, and this is to our knowledge the first case describing syphilitic spondylitis in early acquired syphilis. CASE PRESENTATION: We here describe destructive osteitis in the vertebral column as the initial manifestation of early acquired syphilis in a 24-year-old caucasian homosexual male with HIV infection. The diagnosis was reached by universal bacterial PCR and DNA sequencing of the DNA product. It was confirmed by PCR specific for Treponema pallidum, immunohistochemistry and detection of increasing antibody titer. CONCLUSIONS: As syphilis has re-emerged in Western countries and remains a worldwide common disease it is important to have in mind as a causative agent of skeletal symptoms, especially among HIV-infected individuals or men who have sex with men (MSM).

Patterns of syphilis testing in a large cohort of HIV patients in Ontario, Canada, 2000-2009.

BACKGROUND: Since 2000, reported syphilis cases increased ten-fold in Canada, particularly among men who have sex with men (MSM) co-infected with HIV. We characterized temporal patterns of of syphilis testing in a large cohort of HIV patients in Ontario, Canada. METHODS: We analyzed data from a multi-site cohort of people in HIV care from 2000 to 2009. Data were obtained from medical charts, interviews and record linkage with the syphilis test database at the Public Health Ontario Laboratories. We estimated the proportion that had syphilis testing at least once per year and the period and annual prevalence of reactive tests. RESULTS: Among 4232 participants, the annual proportion tested rose from 2.7% (95%CI 1.9, 3.5) in 2000 to 54.6% (95%CI 52.9, 56.3) in 2009. Testing was most common for participants who were men who have sex with men (MSM), aged <30, recently diagnosed with HIV, were antiretroviral treatment naive, had routine HIV lab testing at least twice in that year, or tested for syphilis in the preceding year. The proportion with at least one reactive test in 2000-09 was 21.0% (95%CI 19.4, 22.7) for MSM, 5.3% (95%CI 3.3, 7.4) for non-MSM males, and 2.6% (95%CI 1.2, 4.0) for women. Among MSM, the annual prevalence of reactive syphilis tests with high RPR titre (≥1:16) peaked at 3.8% in 2009. CONCLUSIONS: The burden of syphilis co-infection rose considerably among HIV-positive MSM, such that by 2009, at least 1 in 5 men had laboratory evidence of current or past infection. Interventions may be needed to boost syphilis testing to achieve goals set by guidelines even in settings with universal health care.

Prospective cohort study of HIV incidence and molecular characteristics of HIV among men who have sex with men(MSM) in Yunnan Province, China.

BACKGROUND: Yunnan has the largest number of reported HIV/AIDS cases among all Chinese provinces, the reported prevalence of HIV among Yunnan men who have sex with men (MSM) passed 10%, while HIV incidence epidemic and molecular characteristics of new infected Yunnan MSM were not evaluated before. METHODS: An 18 months prospective followed up with a frequency of 3 month per visit were conducted among HIV seronegative MSM in Kunming cityduring 2009-2011. Interviewer-administrated questionnaires were carried out. Blood specimens were obtained to test for syphilis and HIV, in which HIV were evaluated by standard HIV enzyme immunoassay (EIA) and HIV nucleic acid amplification testing (NAAT). Near full-length regions of the HIV-1 were evaluated for subtyping, primary drug resistance mutations. RESULTS: During the follow-up 70.1% of the recruited 378 MSM retained in the cohort. Eleven MSM seroconverted to HIV and fifteen MSM seroconverted to syphilis. The HIV incidence and syphilis incidence was 3.5 (95% CI 1.8-6.2) cases /100 person year(PY) and 5.3 (95% CI 3.0-8.7) cases/100 PY, respectively. Multivariate analysis showed that baseline syphilis infection (aHR, 17.7), occupation (students vs. others [aHR, 5.7], retirees vs. others [aHR, 4.1]), bleeding experience after receptive anal intercourse (aHR,7.6), and minority ethnic(vs. Han) [aHR, 5.7] were independent risk factors for HIV seroconversion(each P<0.05). Among the 7/11 successfully amplified near full-length sequences, 71.4% (5/7) were CRF01_AE, and 28.6% (2/7) were CRF07_BC. Two HIV transmission pairs were detected among seroconverted minority ethnic MSM. CONCLUSIONS: HIV incidence was moderately high among Yunnan MSM. Yunnan province need to strengthen both HIV and syphilis screening among MSM population. Some subpopulations of MSM, such as students, retirees and minority ethnic groups require more HIV epidemic surveillance and strengthened behavior interventions. HIV subtypes and primary drug resistance should be continually monitored to track cross-group transmission of HIV strains.

Syphilis as a diagnosis of liver abnormalities in HIV.

In order to investigate syphilitic liver involvement in HIV-infected patients, a single-centre retrospective study of a cohort of HIV-infected patients with syphilis was performed at the Infectious Diseases Clinic of Perugia, Italy, between December 2002 and March 2010. Fifty HIV-infected patients were identified with syphilis plus baseline and follow-up liver tests. The following syphilis diagnoses were recorded: 19 secondary (38%), 26 latent (52%), and 5 tertiary/neurosyphilis (12%). Syphilitic hepatitis was found in 5/50 (10%) patients. This finding supports the importance of including syphilis in the differential diagnosis of liver enzyme abnormalities in HIV-infected patients. An early diagnosis of syphilitic hepatitis can lead to rapid normalization of liver function following appropriate therapy, prevents the progression of syphilis, and limits the further spread of sexually transmitted diseases, including HIV.

Serological response to treatment of syphilis according to disease stage and HIV status.

BACKGROUND: Serology is the mainstay for syphilis diagnosis and treatment monitoring. We investigated serological response to treatment of syphilis according to disease stage and HIV status. METHODS: A retrospective cohort study of 264 patients with syphilis was conducted, including 90 primary, 133 secondary, 33 latent, and 8 tertiary syphilis cases. Response to treatment as measured by the Venereal Disease Research Laboratory (VDRL) test and a specific IgM (immunoglobulin M) capture enzyme-linked immunosorbent assay (ELISA; Pathozyme-IgM) was assessed by Cox regression analysis. RESULTS: Forty-two percent of primary syphilis patients had a negative VDRL test at their diagnosis. Three months after treatment, 85%-100% of primary syphilis patients had reached the VDRL endpoint, compared with 76%-89% of patients with secondary syphilis and 44%-79% with latent syphilis. In the overall multivariate Cox regression analysis, serological response to treatment was not influenced by human immunodeficiency virus (HIV) infection and reinfection. However, within primary syphilis, HIV patients with a CD4 count of <500 cells/µL had a slower treatment response (P = .012). Compared with primary syphilis, secondary and latent syphilis showed a slower serological response of VDRL (P = .092 and P < .001) and Pathozyme-IgM tests (P < .001 and P = .012). CONCLUSIONS: The VDRL should not be recommended as a screening test owing to lack of sensitivity. The syphilis disease stage significantly influences treatment response whereas HIV coinfection only within primary syphilis has an impact. VDRL test titers should decline at least 4-fold within 3-6 months after therapy for primary or secondary syphilis, and within 12-24 months for latent syphilis. IgM ELISA might be a supplement for diagnosis and treatment monitoring.

Syphilis with HIV in Florence, 2003-2009: a 7-year epidemiological study.

The aims of this study were to describe the trend of acquired syphilis in the city of Florence and its province over a 7-year period, to investigate sexual behaviours in the syphilis-infected population and to analyse syphilis/HIV co-infection. A total of 259 patients were classified according to age, sex and HIV infection. We estimated that from 2004 to 2008 cases increased by 248%. Most patients with concurrent HIV infection were male (31-45 years), but 40- to 60-year-old men who had sex with men predominated in both male and HIV-positive patients. Oral sex was identified as the most significant route of transmission, although most patients did not consider it so. Late-presenters with HIV accounted for 33% of HIV-positive patients: they were unaware of their HIV status and showed syphilis lesions only. In these cases, syphilis heralded the presence of HIV infection and allowed earlier diagnosis.

Trends of HIV/Syphilis/HSV-2 seropositive rate and factors associated with HSV-2 infection in men who have sex with men in Shenzhen, China: A retrospective study.

OBJECTIVES: To analyze the trends of HIV/syphilis/HSV-2 seropositive rate and explore the related factors with HSV-2 infection to provide the basis for adjusting STD intervention strategies and formulating prevention and control measures among MSM in Shenzhen. METHODS: Time-location sampling was conducted among MSM in Shenzhen in 2012, 2014, 2016, and 2018. Data on demographics, sexual behaviors and the laboratory test results of HIV, syphilis, HSV-2 were collected. The χ2 trend test was used to analyze the trends of HIV/syphilis/HSV-2 seropositive rate. The binary logistic regression model was used to explore the factors associated with HSV-2 infection. RESULTS: The seropositive rate of HIV fell significantly from 15.9% in 2012 to 8.7% in 2018 (Ptrend = 0.003), syphilis seropositive rate was significantly decreased from 20.4% in 2012 to 14.8% in 2018 (Ptrend = 0.025), HSV-2 seropositive rate had no significant change (16.7% in 2012 to 14.0% in 2018; Ptrend = 0.617). In principal component logistic regression analysis showed that FAC1_1 (X1 = Ever had sex with female, X2 = Gender of first sexual partner, X3 = Marital status, X4 = Age group), FAC2_1 (X5 = Education, X6 = Monthly income (RMB), X7 = Frequency of condom use in anal sex with men in the past 6 months), and FAC4_1 (X9 = History of STDs) were significantly associated with HSV-2 infection. CONCLUSIONS: The seropositive rates of HIV and syphilis have dropped significantly but are still high. HSV-2 seropositive rate had no significant change and maintained a high level. It is necessary to continue strengthening HIV and syphilis interventions among MSM in Shenzhen. HSV-2 detection and intervention are urgently required for MSM, which might be another effective biological strategy further to control the HIV epidemic among MSM in Shenzhen.

Anicteric cholestasis among HIV infected patients with syphilis.

In Martinique, among 9 HIV carriers recently diagnosed with early syphilis, 7 had biologic cholestasis. Less than half of the patients had been diagnosed on clinical grounds for syphilis (cutaneous eruption or syphilis in partner), whereas most of them were diagnosed on a systematic screening of HIV infected patients.

Associations between impulsivity, risk behavior and HIV, HBV, HCV and syphilis seroprevalence among female prisoners in Indonesia: A cross-sectional study.

HIV, hepatitis B and C, and syphilis share common transmission routes of which primarily unsafe sexual contact and injecting drug use are important. Impulsivity is a major factor contributing to this transmission risk behavior; however comprehensive studies within female, prison, and Asian populations are scarce. This cross-sectional study aims to delineate the contributions of different aspects of impulsivity to risk behavior, among female inmates living in a prison in Jakarta (N = 214). The relationships between various aspects of impulsivity, risk behaviors and seropositivity were tested using analyses of variance and logistic regression analyses. Motor impulsivity was related to alcohol use, reward-related impulsivity to drug use, and cognitive/goal-directed impulsivity to sexual risk behavior. Finally, goal-directed impulsivity was also directly associated with seropositivity. Specific aspects of impulsivity are associated with different types of risk behavior in Indonesian female prisoners, which can be relevant for future studies on infection prevention strategies for such a population.

Laboratory assessment of SD Bioline HIV/Syphilis Duo Kit among pregnant women attending antenatal clinic Mayuge Health Center III, East central Uganda.

OBJECTIVE: Efforts to dual eradication of mother-to-child transmission of human immune deficiency virus (HIV) and syphilis have improved in the previous decades. This has however been hindered by limited validation studies. A cross-sectional study was conducted among adult pregnant women attending antenatal care clinic at Mayuge Health Center III. Two milliliters of venous blood were collected into Ethylene di-amine tetra acetic acid vacutainers, and tested for HIV and syphilis using the SD Bioline HIV/Syphilis Duo assay, and the national HIV and syphilis testing algorithm. Sensitivity and specificity were calculated for the Duo Kit against the gold standards within 95% confidence intervals. RESULTS: Three hundred and eighty-two (382) participants were enrolled. Their mean age was 25.8 years. The prevalence of HIV was 1.8% (95% confidence interval 1.23-2.41); while that of syphilis was 2.1% (95% confidence interval 1.81-2.54), and the dual infection was 0.52% (95% confidence interval 0.37-0.92). The sensitivity and specificity of the SD Bioline HIV/Syphilis Duo assay were all 100.0% (95% confidence interval 99.5 to 100.0 and 98.6 to 100.0, respectively). The performance of the SD Bioline HIV/Syphilis Duo Kit was optimal, reassuring its aptness for use, and favorable qualities to a limited resource setting.

Immunological Changes in Monocyte Subsets and Their Association With Foxp3+ Regulatory T Cells in HIV-1-Infected Individuals With Syphilis: A Brief Research Report.

The incidence of syphilis has increased dramatically in men who have sex with men (MSM), especially those with HIV-1 infection. Treponema pallidum and HIV-1 are bidirectionally synergistic, accelerating disease progression reciprocally in co-infected individuals. We have shown that monocytes have different effects on T helper cells at different stages of HIV-1 infection. However, the immunological changes in the three monocyte subsets and in regulatory T cells (Tregs), and the associations between these cell types during syphilis infection among HIV-1-infected MSM remain unclear. Herein, we used cell staining methods to explore changes in monocyte subsets and Tregs and any associations between these cells. We found that the frequency of classical monocytes was higher in the rapid plasma reagin (RPR+) group than in the healthy controls (HCs) and the chronic HIV-1 infection (CHI) plus RPR+ (CHI&RPR+) group. The frequencies of Foxp3+CD25+CD45RA+ and Foxp3+Helios+CD45RA+ Tregs were significantly higher in the RPR+, CHI, and CHI&RPR+ groups than in HCs, whereas the frequency of CD45RA+ Tregs was lower in the CHI&RPR+ group than in CHI group. The frequencies of Foxp3+CD25+CD45RO+ and Foxp3+Helios+CD45RO+ Tregs were lower in the RPR+, CHI, and CHI&RPR+ groups than in HCs. The frequency of intermediate monocytes was inversely correlated with the frequency of CD45RA+ Tregs and positively correlated with the frequency of CD45RO+ Tregs. These results demonstrate for the first time that intermediate monocytes control the differentiation of Treg subsets in Treponema pallidum/HIV-1 co-infections. These findings provide new insights into an immunological mechanism involving monocytes/Tregs in HIV-infected individuals with syphilis.

Brief Report: Syphilis Coinfection Is Not Associated With an Increased Risk of Virologic Failure Among HIV-Positive Men Who Have Sex With Men on Antiretroviral Therapy.

BACKGROUND: Incidence of syphilis continues to increase among HIV-positive men who have sex with men (MSM) in Ontario. Our objective was to determine the effect of acute syphilis on virologic failure (VF) among virally suppressed HIV-positive MSM taking antiretroviral therapy (ART) and determine if the relationship is confounded by drug use. SETTING: The OHTN Cohort Study is a voluntary cohort of people receiving HIV care in Ontario. Syphilis and viral load (VL) data were retrieved via linkage with the provincial laboratory. METHODS: Analyses included 2632 MSM from 2008 to 2015, on ART, with ≥1 questionnaire and 2 consecutive VL of <50 copies per milliliter 6 months apart. VF was defined as (1) VL of ≥1000 copies per milliliter or (2) 2 consecutive VLs of ≥200 copies per milliliter ≥1 month apart. We modeled acute syphilis as a time-varying covariate on VF using Poisson regression. Time-varying drug use was assessed for confounding using an iterative process where potential confounders were removed and then reintroduced into the model. Our model allowed for repeat observations using generalized estimating equations. RESULTS: VF incidence was 3.5 per 100 person-years [95% confidence interval (CI): 3.4 to 4.2]. The rate ratio for VF for acute syphilis was 1.5 (95% CI: 0.9 to 2.4) in the unadjusted model; 1.6 (95% CI: 1.0 to 2.4) in the model adjusted for age, education, region, and income; and 1.2 (95% CI: 0.7 to 1.9) in the final model with additional adjustment for drug use. CONCLUSIONS: Acute syphilis was not associated with VF among virologically suppressed MSM on ART. Consequently, ART may still reduce HIV transmission risk to sexual partners.