Incidence of syphilis among HIV-infected men in Singapore, 2006–2017: temporal trends and associated risk factors

Abstract

ObjectiveThere have been recent reports globally on substantial increase in syphilis diagnoses particularly among high-risk men. The aim of this study was to assess temporal trends of incident syphilis and associated risk factors among HIV-infected men in Singapore.MethodsWe conducted retrospective cohort analysis using the clinical database maintained by the Clinical HIV Programme at the National Centre for Infectious Diseases, Singapore. HIV-infected men with a negative syphilis result at baseline who had undergone at least one subsequent test in 2006–2017 were included. Factors associated with incident syphilis were investigated using Cox proportional hazards regression analyses.ResultsA total of 1069 HIV-infected men were tested for syphilis at least once following their negative baseline test during the 12-year period, and they contributed 4284 person-years of follow-up (PYFU). There were 266 cases of incident syphilis, giving an overall incidence of 6.21 per 100 PYFU (95% CI 5.49–7.00). The incidence of syphilis per 100 PYFU increased from 1.21 (95% CI 0.33 to 3.10) in 2010 to 26.04 (95% CI 19.97 to 33.40) in 2017. In the multivariable model, risk factors for syphilis seroconversion were: age 15–24 years at HIV diagnosis (adjusted HR (aHR) 1.64, 95% CI 1.05 to 2.56) versus ≥45 years, being Chinese (aHR 1.82, 95% CI 1.01 to 3.29) versus Indian and other minority ethnic groups, men having sex with men (MSM) (aHR 3.29, 95% CI 2.22 to 4.87) versus heterosexuals, and HIV diagnosis in later periods of 2009–2011 (aHR 1.96, 95% CI 1.41 to 2.74), 2012–2014 (aHR 3.96, 95% CI 2.68 to 5.83) and 2015–2017 (aHR 7.94, 95% CI 4.52 to 13.95) versus 2006–2008.ConclusionThe annual incidence rate of syphilis in HIV-infected men was on the rise, and it was consistently higher among MSM than in heterosexual men. The findings supported regular screening for syphilis and enhanced behavioural interventions in Singapore.

Incidence and risk factors for syphilis infection among men who have sex with men: A cohort study from an urban sexual health clinic in Jakarta, Indonesia

“…Studies in some countries have shown a higher syphilis infection among MSM associated with higher frequency of condomless anal intercourse, younger age, and number of sex partners. 7,14,22 In contrast, our study showed no association between age and incident syphilis infection. This finding is similar to studies in Peru and Shenzhen, 23,24 but differs from finding reported in China, Tokyo and Singapore and other Asian countries that reported more syphilis infection in younger age.…”

“…6 Our incidence rate is lower than reported from Singapore in 2017 incidence among MSM was 26.04 (19.97–33.40 per 100 PYFU. 7 Our findings are similar to a meta-analysis which reported incidence rates ranging from 1.8 to 14.9 per 100 PYFU. 12…”

“…6 Singapore reported a 26 fold increase in syphilis incidence, 26.04% (95% CI 19.97–33.40) among HIV infected MSM in 2017 compared to 1.21%. 7…”

Hepatitis C virus infection in HIV-infected men in Singapore, 2006–2018: incidence and associated factors

“…The increase in HCV incidence coincided with the rising trend in the incidence of syphilis infection among HIV-infected men who had ever sought HIV care at the largest referral centre in Singapore. 35 In the Swiss HIV cohort study, the significant increase in syphilis acquisition among MSM mirrored that of HCV infection incidence. 15,36 In the United States, Western Europe, Australia and China, recent upsurges of syphilis infections have also been reported, particularly among highrisk groups such as gay, bisexual and other MSM.…”

Prevalence of Opportunistic Infections and Associated Factors in HIV-Infected Men Who Have Sex With Men on Antiretroviral Therapy in Bach Mai Hospital, Hanoi, Vietnam: A Case-Control Study

“…The reason for the difference has not been established. One of the reasons for the difference is that HIV-infected heterosexual patients have been infected for longer period of time, therefore they might have been treated; while the MSM, on the other hand, has recently been infected with HIV and thus they might have just currently been diagnosed (Ang et al, 2020;Roth et al, 2020). Ang et al also confirmed that the annual incidence rate of syphilis was consistently higher among MSM than in heterosexual men and the incidence was on the rise especially in MSM group with the risk factors including younger age, race, and being an MSM.…”