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. 2018 Mar 13;18(1):125.
doi: 10.1186/s12879-018-3038-4.

Increasing incidence of syphilis among patients engaged in HIV care in Alberta, Canada: a retrospective clinic-based cohort study

Raynell Lang  1 , Ron Read  1 , Hartmut B Krentz  2 , Soheil Ramazani  2 , Mingkai Peng  3 , Jennifer Gratrix  4 , M John Gill  5
Affiliations

Increasing incidence of syphilis among patients engaged in HIV care in Alberta, Canada: a retrospective clinic-based cohort study

Raynell Lang et al. BMC Infect Dis. .

Abstract

Background: Syphilis is a global health concern disproportionately affecting HIV-infected populations. In Alberta, Canada, the incidence of syphilis in the general population has recently doubled with 25% of these infections occurring in HIV-infected patients. The Southern Alberta HIV Clinic (SAC) and Calgary STI Program (CSTI) analyzed the epidemiologic characteristics of incident syphilis infections in our well-defined, HIV-infected population over 11 years.

Methods: Since 2006, as routine practice of both the Southern Alberta Clinic (SAC) and Calgary STI Programs (CSTI), syphilis screening has accompanied HIV viral load measures every four months. All records of patients who, while in HIV care, either converted from being syphilis seronegative to a confirmed seropositive or were re-infected as evidenced by a four-fold increase in rapid plasma reagin (RPR) after past successful treatment, were reviewed.

Results: Incident syphilis was identified 249 times in 194 HIV-infected individuals. There were 36 individuals with repeated infections (28.5% of episodes). Following a prior decline in annual incident syphilis rates, the rates have tripled from 8.08/1000 patient-years (95% confidence interval (CI): 4.14-14.75) in 2011, to 27.04 per 1000 person-years (95% CI: 19.45-36.76) in 2016. Half of the syphilis episodes were asymptomatic. Patients diagnosed with syphilis were twice as likely not to be taking ART and had a higher likelihood of having plasma HIV RNA viral loads > 1000 copies/mL (19%). Incident syphilis was seen predominantly in Caucasians (72%, P < 0.001), males (94%, P < 0.001) and men who have sex with men (MSM) as their HIV risk activity (75%, P < 0.001).

Conclusions: We have highlighted the importance of a regular syphilis screening program in HIV-infected individuals demonstrated by increasing rates of incident syphilis in our region. Targeted preventative strategies should be directed towards HIV-infected populations identified at highest risk, including; MSM, prior alcohol abuse, prior recreational drug use and those with prior syphilis diagnoses.

Keywords: Canada; HIV/AIDS; Incidence; Syphilis.

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Conflict of interest statement

Ethics approval and consent to participate

Ethics approval was obtained through the University of Calgary Bioethics committee as a quality assurance project through A Project Ethics Community Consensus Initiative (ARECCI). Approval was granted both verbally and written on Aug 23, 2016. Informed consent was deemed unnecessary as per ethics approval via ARECCI do to the non-identifying nature of this grouped data.

Consent for publication

Not applicable.

Competing interests

We have no relevant conflicts of interest to disclose. This research was presented at CROI 2017 in Seattle, WA as a poster.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Age and Sex adjusted Incidence Rates among Individuals with HIV in Care at Southern Alberta Clinic 2006–2016. This figure demonstrates the rise in incident rate per 1000 patient years of syphilis infection in the HIV-infected individuals at SAC between 2006 and 2016
Fig. 2
Fig. 2
Repeat Incident Episodes of Syphilis in the HIV Positive Individuals Per Year. This figure is demonstrating the number of syphilis infection each year divided by number of repeat infection. As seen there has been an increase in number of syphilis episodes from 2006 to 2016, however the number of repeat cases has also increased
See this image and copyright information in PMC

References

    1. World Health Organization. (2012) Global incidence and prevalence of selected curable sexually transmitted infections – 2008. http://www.who.int/reproductivehealth/publications/rtis/stisestimates/en/. Accessed 2 Nov 2016.
    1. Trotten S, Maclean R, Payne E. Infectious syphilis in Canada: 2003–2012, CCDR. Center for Communicable Diseases and Infection Control, Public Health Agency of Canada. CCDR. 2015;41(2). - PMC - PubMed
    1. Alberta Government. Sexually transmitted infections have reached outbreak levels in Alberta. 2016 Apr 26. https://www.alberta.ca/release.cfm?xID=4163947EECDEA-024A-0016-6E2A2E61E.... Accessed 2 Nov 2016.
    1. Cope AB, Crooks AM, Chin T, Kuruc JD, McGee KS, Eron JJ, et al. Incident sexually transmitted infection as a biomarker for high risk sexual behaviour following diagnosis with acute HIV. Sex Transm Dis. 2014;41(7):447–452. doi: 10.1097/OLQ.0000000000000147. - DOI - PMC - PubMed
    1. Palacios R, Jimenez-Onate F, Aguilar M, Galindo MJ, Ocampo A. Berenguer et al. impact of syphilis infection on HIV viral load and CD4 cell counts in HIV-infected patients. J Acquir Immune Defic Syndr. 2007;44(3):356–359. doi: 10.1097/QAI.0b013e31802ea4c6. - DOI - PubMed

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