Chlamydia: Hidden Infections Management in Primary care (CHIMP)

The majority of Sexually Transmitted Infections (STI) diagnoses in the Netherlands are made by GPs. Yet, the current STI control in the GP setting fails to appropriately reach the GP population and is only focused on urogenital chlamydia infections (missing anorectal positives). Infections remain hidden due to suboptimal retesting advice and strategies (missing repeat positives), and suboptimal partner notification (missing peer positives). Thereby many chlamydia infections remain hidden and will contribute to the ongoing spread of chlamydia. Missing anorectal positives: Treatment of a concomitant anorectal chlamydia infection (women with both urogenital and anorectal chlamydia infection) or isolated anorectal chlamydia infection warrants treatment with doxycycline instead of the standard azithromycin. Yet diagnostic testing for anorectal chlamydia infections in general practice is nearly non-existent. Missing repeat positives: Evidence from different populations shows that up to 25% of women with a chlamydia infection retest positive when retested 4 to 6 months after the initial infection, supporting recent recommendations to routinely retest chlamydia positives. Yet, the current Dutch GP guideline on The STD (Sexual Transmitted Diseases) Consultation does not recommend routine retesting. Promising strategies to increasing chlamydia retesting include electronic reminders (e-mail reminder systems and short text messaging (SMS) technology) and the offer of mailed test kits for home-collection on retesting In this proposed CHIMP study (Chlamydia Hidden Infection Management in Primary care) we aim to determine the prevalence of anorectal chlamydia infections in women presenting in general practice population (WP1) and to evaluate the effect of brief GP counselling, electronic patient reminders and the offer of home-collected chlamydia testing kits on the retesting rate of general practice patients who tested positive for chlamydia (WP2). Moreover we will study important determinants and influencing factors of facilitators and barriers towards optimal chlamydia management, including partner notification, in general practice (WP3). Workpackage 1 will focus on determining the prevalence of anorectal chlamydia infection rates in the general practice population by including an anorectal swab in routine general practice chlamydia test kits provided to those women consulting in general practice in which the GP decides to order chlamydia test. In this prospective observational cohort study in general practice we aim to recruit 1500 patients to determine the anorectal chlamydia infection rate of women, and calculate the number of double infections (hence those with an urogenital and anorectal chlamydia infection) and the number of isolated anorectal chlamydia positives (hence those with a positive anorectal swab, but without a concurrent urogenital infection). Workpackage 2 will assess the effect of brief GP counselling, electronic reminders and the additional offer of home-based chlamydia testing kits on chlamydia repeat positives by retesting within one year in general practice. Based on an estimated urogenital infection rate of 10% in the general practice population, we will be able to evaluate the effect of GP brief counselling in 900 chlamydia positive patients (both men and women tested in in 2 years), compared with a 2-year historical cohort. The evaluation of GP brief counselling combined with electronic reminders and the offer to receive a postal home-based chlamydia testing kit on retesting rate and retest positivity, will be able in a population of 150 women (based on a conservative approach of 33% of women consenting to provide an extra anorectal swab, yielding 1500 tests and an estimated urogenital infection rate of 10% in the general practice population). Workpackage 3 will assess knowledge, attitude and practices in chlamydia management, including barriers and facilitators of partner notification of general practitioners, patients and other stakeholders using focus group discussions or a series of semi-structured interviews. While the GP primarily wants to treat his own patients and prevent morbidity and complications from a primary care perspective, retesting and detecting repeat positives will detect hidden positives which is also important from a public health perspective in the containment of chlamydia. The proposed prospective cohort study will show the prevalence of anorectal chlamydia infections and will thereby inform future recommendations in GP STD guidelines for possible additional routine anorectal chlamydia testing (on top of urogenital testing). Furthermore this study will show the acceptability and applicability of promising interventions (electronic reminders and home-based chlamydia test kits for patients) on top of brief GP counselling to retest after a positive chlamydia test in the busy general practice setting.