Factors Associated With Positive Post-Treatment STI Tests and Sexual Knowledge, Attitudes, Behaviors and Practices (ECART-IST)

**Background and Rationale**

Chlamydia trachomatis and Neisseria gonorrhoeae are common sexually transmitted infections (STIs) and remain important public health concerns.

Although effective antibiotic treatments are available, some individuals continue to have positive laboratory tests after treatment. These positive results may be associated with persistent infection, reinfection, or other factors.

Sexual knowledge, attitudes, behaviors, and practices may influence the risk of a positive post-treatment test. However, the relationship between these factors and post-treatment test results remains insufficiently understood.

**Study Objectives**

The primary objective of ECART-IST is to identify factors associated with a positive post-treatment nucleic acid amplification test (NAAT/PCR) for Chlamydia trachomatis and/or Neisseria gonorrhoeae at week 4 and/or week 8, according to the dimensions of a Knowledge, Attitudes, Behaviors, and Practices (KABP) questionnaire.

Secondary objectives include describing participants' sexual health knowledge and behaviors, estimating positive test rates at follow-up visits, and exploring associations with treatment adherence, sexual re-exposure, and other clinical or sociodemographic characteristics.

**Study Design and Procedures**

ECART-IST is a prospective, longitudinal, single-center study conducted at the Centre Hospitalier de Martigues, France.

The study aims to enroll 238 adults with a confirmed Chlamydia trachomatis and/or Neisseria gonorrhoeae infection.

Participants will receive antibiotic treatment according to standard clinical practice. No experimental medication or modification of the usual treatment strategy is planned.

At the initial visit, researchers will collect sociodemographic, clinical, microbiological, and behavioral information. Participants will also complete a KABP questionnaire.

Two additional follow-up visits are scheduled at week 4 (plus or minus 7 days) and week 8 (plus or minus 7 days).

At each follow-up visit, participants will undergo a post-treatment NAAT/PCR test. Researchers will also collect information about treatment adherence, sexual behaviors, possible re-exposure, and changes in KABP questionnaire responses.

When appropriate and technically feasible, bacterial cultures and antimicrobial susceptibility testing may also be performed.

**Statistical Analysis**

The proportion of participants with a positive post-treatment test at week 4 and/or week 8 will be estimated with a 95% confidence interval.

Researchers will compare participants with positive and negative follow-up tests.

Univariable analyses will explore associations between the study outcome and KABP scores, clinical characteristics, treatment adherence, and sexual behaviors.

Multivariable logistic regression will be used to identify factors independently associated with positive post-treatment tests. Results will be expressed as adjusted odds ratios with 95% confidence intervals.

Longitudinal changes in KABP questionnaire scores may also be analyzed using statistical methods appropriate for repeated measurements.

**Expected Contribution**

This study aims to improve understanding of the behavioral, clinical, and microbiological factors associated with positive STI tests after treatment.

Its findings may help healthcare professionals improve patient education, prevention strategies, and follow-up care for people diagnosed with chlamydia or gonorrhea.