High proportions of rectal and pharyngeal chlamydia and gonorrhoea cases among cisgender men are missed using current CDC screening recommendations

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.