High rates of anorectal chlamydia in women: a cross-sectional study in general practice

BACKGROUND: Genital and anorectal Chlamydia trachomatis (CT) frequently present together in sexually transmitted infection (STI) clinics. AIM: To investigate the prevalence of co-occurrent genital and anorectal chlamydia infection, and to study whether sexual behaviour is associated with anorectal infection. DESIGN & SETTING: A cross-sectional study in general practices in the north of the Netherlands. METHOD: Women attending general practice with an indication for genital chlamydia testing were included and asked to complete a structured questionnaire on sexual behaviour. Anorectal infection prevalence was compared according to testing indications: standard versus experimental (based on questionnaire answers). Variables associated with anorectal chlamydia were analysed by univariate and multivariate logistic regression analyses. RESULTS: Data could be analysed for 497 of 515 women included. Overall, 17.8% (n = 87/490) were positive for CT; of these, 72.4% (n = 63/87) had co-occurrent genital and anorectal infection, 13.8% (n = 12/87) had genital infection only, and 12.6% (n = 11/87) had anorectal infection only. Rectal infection was missed in 69.3% of cases using the standard indication alone, while adding the sexual history still missed 20.0%. Age was the only variable significantly associated with anorectal infection. CONCLUSION: The prevalence of anorectal disease is high among women who visit their GP with an indication for genital CT testing. Many anorectal infections are missed despite taking comprehensive sexual histories, meaning that standard treatment of genital infection with azithromycin may result in rectal persistence. Performing anorectal testing in all women with an indication for genital CT testing is, therefore, recommended.