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Factors associated with anorectal Chlamydia trachomatis or Neisseria gonorrhoeae test positivity in women: a systematic review and meta-analysis
  1. Andrew Lau1,
  2. Fabian Yuh Shiong Kong1,
  3. Willa Huston2,
  4. Eric P F Chow3,4,
  5. Christopher K Fairley3,4,
  6. Jane S Hocking1
  1. 1 Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
  2. 2 School of Life Sciences, The University of Technology Sydney, Sydney, New South Wales, Australia
  3. 3 Melbourne Sexual Health Centre, Alfred Health, Carlton, Victoria, Australia
  4. 4 Central Clinical School, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia
  1. Correspondence to Andrew Lau, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia; andrew.lau{at}


Objectives There has been considerable discussion about anorectal Chlamydia trachomatis (CT) in women, with some calling for anorectal CT screening, but little about anorectal Neisseria gonorrhoeae (NG). Given that urogenital NG is more strongly associated with pelvic inflammatory disease, this is an evidence gap. This systematic review and meta-analysis investigates the associations between anorectal CT in women and CT positivity at other sites (urogenital/oropharyngeal) and with anal intercourse, and compares these with anorectal NG within the same study populations.

Methods Electronic databases were searched for English-language studies published to October 2018 using the following terms: (“Chlamydia” OR “Chlamydia trachomatis”) AND ((“anal” OR “rect*” OR “anorect*”) OR (“extra?genital” OR “multi?site”)). Studies were included if anorectal NG data were available. Random-effects meta-analyses calculated pooled estimates; heterogeneity was investigated using meta-regression.

Results 25 studies were eligible. Anorectal CT positivity ranged from 0% to 17.5%, with a summary estimate of 8.0% (95% CI 7.0 to 9.1; I2=88.5%). Anorectal NG positivity ranged from 0% to 17.0%, with a summary estimate of 2.1% (95% CI 1.6 to 2.8; I2=92.7%). The association between urogenital and anorectal positivity was stronger for NG than CT (summary prevalence ratio (PR)=89.3 (95% CI 53.1 to 150.3; I2=80.1%), PR=32.2 (95% CI 25.6 to 40.7; I2=70.3%), respectively), and between oropharyngeal and anorectal positivity it was stronger for NG than CT (PR=34.8 (95% CI 10.2 to 118.2; I2=89.9%), PR=8.8 (95% CI 6.8 to 11.5; I2=58.1%), respectively). Anal intercourse was associated with anorectal NG (PR=4.3; 95% CI 2.2 to 8.6; I2=0.0%) but not with anorectal CT (PR=1.0; 95% CI 0.7 to 1.4; I2=0.0%).

Conclusions Anorectal CT is more common than anorectal NG, but anorectal NG is more strongly associated with anal intercourse, urogenital and oropharyngeal NG, suggesting that ongoing discussion about anorectal CT should also include NG. Longitudinal data are required to further understanding of the aetiology of anorectal STIs and assess whether anorectal screening is needed in women.

Trial registration number CRD42df017080188.

  • chlamydia trachomatis
  • neisseria gonorrhoeae
  • women
  • systematic review, meta-analysis

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  • Handling editor Jackie A Cassell

  • Contributors AL and JSH designed the search strategy and reviewed the abstracts. AL extracted the data, and JSH reviewed the data. AL performed the meta-analysis and meta-regression and wrote the first draft of the paper. JSH, FYSK, WH, EPFC and CKF commented in detail on the drafts and approved the final version.

  • Funding AL is supported by a National Health and Medical Research Council (NHMRC) Postgraduate Scholarship (1133144). JSH is supported by an NHMRC Senior Research Fellowship (1136117).

  • Competing interests None declared.

  • Patient consent for publication Not required.

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

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