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High proportions of rectal and pharyngeal chlamydia and gonorrhoea cases among cisgender men are missed using current CDC screening recommendations
  1. Ryan D Assaf1,2,
  2. Nicole J Cunningham1,
  3. Paul C Adamson3,
  4. Jamieson Trevor Jann1,
  5. Robert K Bolan1
  1. 1 Health Services, Los Angeles LGBT Center, Los Angeles, California, USA
  2. 2 Epidemiology, University of California Los Angeles Jonathan and Karin Fielding School of Public Health, Los Angeles, California, USA
  3. 3 Division of Infectious Diseases, David Geffen School of Medicine, Los Angeles, California, USA
  1. Correspondence to Ryan D Assaf, Health Services, Los Angeles LGBT Center, Los Angeles, California, USA; rassaf{at}


Objectives Pharyngeal and rectal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are often undiagnosed due to their asymptomatic nature. This study aims to determine (1) the prevalence of CT/NG infections by anatomical site among cisgender men; (2) the proportion of missed CT/NG rectal/pharyngeal infections if urogenital testing alone was performed or screening depended on self-reported behaviour alone; and (3) the predictive probability of self-reported behaviours for rectal CT/NG.

Methods This cross-sectional study used electronic health records collected at a sexual health clinic in Los Angeles from 18 November 2018 until 28 February 2020. The included patients were ≥18 years of age cisgender men who received CT/NG testing at least once during the study period. We calculated the proportion of missed pharyngeal/rectal CT/NG infections if only urogenital testing had been done and if testing was based only on self-reported anal sex. Separately, we ran logistic regressions for predictive probability of self-reported anal sex on CT/NG rectal infections.

Results Overall, there were 13 476 unique patients with 26 579 visits. The prevalence of any extragenital CT/NG infection was 37.28%. Over 80% rectal/pharyngeal CT cases and over 65% rectal/pharyngeal NG cases would be missed if urogenital testing alone was performed. Likewise, over 35% rectal CT/NG cases would be missed had testing relied on self-reported sexual behaviours alone.

Conclusions The proportion of missed rectal and pharyngeal CT/NG infections is high. Our data from a sexual health clinic lend support to three-site opt-out testing for cisgender men attending a sexual health/Lesbian, Gay, Bisexual, Transgender, Queer/Questioning (LGBTQ+) specialty clinic regardless of their sexual orientation or reported sexual behaviours.

  • Chlamydia trachomatis
  • epidemiology
  • men
  • Neisseria gonorrhoeae
  • sexual health

Data availability statement

Data are available upon reasonable request.

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Data availability statement

Data are available upon reasonable request.

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  • Handling editor Erica L Plummer

  • Contributors RDA: conception, design, analysis and interpretation of data, drafting, critically revising the manuscript, final approval, and is responsible for the overall content as the guarantor. NJC: conception, design, interpretation of data, drafting, critically revising the manuscript. PCA: interpretation of data, critically revising the manuscript. JTJ, RKB: critically revising the manuscript.

  • Funding PCA’s work was supported by the National Institutes of Health (T32MH080634).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.