Risk factors for chlamydial infection in chlamydia contacts: a questionnaire-based study

Abstract

Background and methodology Treatment of individuals with chlamydial infection and their sexual partners is an important aspect of reproductive health care. Partners of infected individuals are currently offered 'epidemiological treatment', which means that they are offered antibiotic treatment at their fi rst visit without waiting for the result of their chlamydia test. We carried out a study to identify the risk factors for chlamydial infection in partners of infected individuals. Individuals attending a genitourinary clinic as chlamydia contacts were identifi ed and asked to complete a questionnaire about their relationship with the index case and their prior sexual history. The result of their chlamydia test was then analysed against those variables. Results A total of 115 chlamydia contacts were analysed in this study; 60 (52%) were found to be positive for chlamydial infection. In a multivariate analysis, young age, more than one episode of sexual intercourse with the infected partner and a greater total number of sexual partners were associated with a positive chlamydia result. A prediction model for chlamydial infection using these risk factors had a discriminatory ability quantifi ed by an area under the curve (AUC) of 0.76 (95% CI 0.66-0.85). Discussion and conclusions The risk factors identifi ed can be used when discussing epidemiological treatment with individuals who attend sexual health services as chlamydia contacts, or to target clinic resources to a higherrisk group. Larger studies will be necessary to assess the benefi ts and risks of changing to a policy of offering epidemiologic treatment to 'high-risk' contacts only, identifi ed using a predictive model such as the one described here.

Chlamydia infection in individuals reporting contact with sexual partners with chlamydia: a cross-sectional study of sexual health clinic attendees

“…In heterosexuals, chlamydia rates of 52–68% have been reported in contacts of sexual partners with confirmed chlamydia infection 14 26 27. In this study, the proportion diagnosed with chlamydia in the small number of contacts where chlamydia was confirmed in a sexual partner is consistent with this.…”

Mycoplasma genitalium Infection in Adults Reporting Sexual Contact with Infected Partners, Australia, 2008–2016

“…Concordance for M. genitalium infection in heterosexual dyads in which both partners were tested at our service was 47%, reflecting the high risk for concurrent infection in heterosexual partnerships. Overall, the prevalence of M. genitalium infection in heterosexual men and women was within the range reported for chlamydial infection in published studies ( 23 – 26 ).…”

“…The higher the likelihood of infection in a contact of a person with confirmed infection, the stronger the argument for presumptive treatment. Presumptive treatment for chlamydial infection, a sexually transmitted infection with similar characteristics to M. genitalium infection, is recommended based on prevalence estimates of 36%–68% among contacts of sex partners with confirmed chlamydial infection ( 23 – 26 ).…”

Modelling with multiple explanatory variables

“…This statistical technique has been used in two papers in this issue of the Journal, namely those by Kotb et al 1 and Schembri et al 2 These notes are intended to provide a supplementary explanation of this method. [See Box 1 for a glossary of terms used in this article.…”