The characteristics of patients frequently tested and repeatedly infected with Chlamydia trachomatis in Southwest Limburg, the Netherlands

Determinants and prediction of Chlamydia trachomatis re-testing and re-infection within 1 year among heterosexuals with chlamydia attending a sexual health clinic

Background

Chlamydia trachomatis (chlamydia) is one of the most common sexually transmitted infections (STI) globally, and re-infections are common. Current Australian guidelines recommend re-testing for chlamydia 3 months after treatment to identify possible re-infection. Patient-delivered partner therapy (PDPT) has been proposed to control chlamydia re-infection among heterosexuals. We aimed to identify determinants and the prediction of chlamydia re-testing and re-infection within 1 year among heterosexuals with chlamydia to identify potential PDPT candidates.

Methods

Our baseline data included 5,806 heterosexuals with chlamydia aged ≥18 years and 2,070 re-tested for chlamydia within 1 year of their chlamydia diagnosis at the Melbourne Sexual Health Center from January 2, 2015, to May 15, 2020. We used routinely collected electronic health record (EHR) variables and machine-learning models to predict chlamydia re-testing and re-infection events. We also used logistic regression to investigate factors associated with chlamydia re-testing and re-infection.

Results

About 2,070 (36%) of 5,806 heterosexuals with chlamydia were re-tested for chlamydia within 1 year. Among those retested, 307 (15%) were re-infected. Multivariable logistic regression analysis showed that older age (≥35 years old), female, living with HIV, being a current sex worker, patient-delivered partner therapy users, and higher numbers of sex partners were associated with an increased chlamydia re-testing within 1 year. Multivariable logistic regression analysis also showed that younger age (18-24 years), male gender, and living with HIV were associated with an increased chlamydia re-infection within 1 year. The XGBoost model was the best model for predicting chlamydia re-testing and re-infection within 1 year among heterosexuals with chlamydia; however, machine learning approaches and these self-reported answers from clients did not provide a good predictive value (AUC < 60.0%).

Conclusion

The low rate of chlamydia re-testing and high rate of chlamydia re-infection among heterosexuals with chlamydia highlights the need for further interventions. Better targeting of individuals more likely to be re-infected is needed to optimize the provision of PDPT and encourage the test of re-infection at 3 months.

Patterns of sexual behaviour associated with repeated chlamydia testing and infection in men and women: a latent class analysis

BACKGROUND

Adolescents and young adults are at higher risk of acquiring Chlamydia trachomatis infection (chlamydia), so testing is promoted in these populations. Studies have shown that re-testing for chlamydia is common amongst them. We investigated how sexual risk behaviour profiles are associated with repeated testing for chlamydia.

METHODS

We used baseline data from a cohort of 2814 individuals recruited at an urban STI -clinic. We applied latent class (LC) analysis using 9 manifest variables on sexual behaviour and substance use self-reported by the study participants. We fitted ordered logistic regression to investigate the association of LC membership with the outcomes repeated testing during the past 12 months and lifetime repeated testing for chlamydia. Models were fit separately for men and women.

RESULTS

We identified four LCs for men and three LCs for women with increasing gradient of risky sexual behaviour. The two classes with the highest risk among men were associated with lifetime repeated testing for chlamydia: adjOR = 2.26 (95%CI: 1.50-3.40) and adjOR = 3.03 (95%CI: 1.93-4.74) as compared with the class with lowest risk. In women, the class with the highest risk was associated with increased odds of repeated lifetime testing (adjOR =1.85 (95%CI: 1.24-2.76)) and repeated testing during past 12 months (adjOR = 1.72 (95%CI: 1.16-2.54)). An association with chlamydia positive test at the time of the study and during the participant's lifetime was only found in the male highest risk classes.

CONCLUSION

Prevention messages with regard to testing for chlamydia after unprotected sexual contact with new/casual partners seem to reach individuals in highest risk behaviour classes who are more likely to test repeatedly. Further prevention efforts should involve potentially more tailored sex-specific interventions taking into consideration risk behaviour patterns.

Chlamydia trachomatis Infections in a Tertiary Care Portuguese Hospital: An 11-Year Retrospective Study

BACKGROUND

Chlamydia trachomatis infections remain a burden worldwide. The goals of this study were to determine the number of C. trachomatis infections per year, characterize the demographic traits of the infected population and identify the associated sexually transmitted infections (STI), over the last 11 years, in Lisbon main Hospital Centre.

MATERIALS AND METHODS

Laboratorial confirmed C. trachomatis infections diagnosed between January 1st, 2009 and December 31st, 2019 were evaluated.

RESULTS

A total of 6404 samples were collected, with 602 being positive for C. trachomatis, corresponding to 550 patients. 60% of diagnoses were made by dermatovenereologists and most cases occurred in males (n = 371; 67.5%), with a median age of 26.1 years (standard deviation 7.98), ranging from 13 to 68 years. More than half the cases (51.3%) occurred below the age of 25 years. In 87 patients (15.8%) there was previous history of STI, in 198 patients (36%) a concomitant STI was present and 43 patients (7.8%) developed a posterior STI. Concerning follow-up, 196 patients (corresponding to 35.6% of total patients) did not show for a re-evaluation after the diagnosis was made.

CONCLUSION

Confirmed cases of C. trachomatis infection have risen along the years, affecting mainly people younger than 25 years. C. trachomatis infection is especially associated with Neisseria gonorrhoeae infection, but other STI are also very prevalent. Considering the potential complications of C. trachomatis infection, screening and treatment are necessary. The high percentage of diagnoses made by dermatovenereologists support the pivotal role of dermatovenereology in diagnosing C. trachomatis infections.

Chlamydia trachomatis Infections in a Tertiary Care Portuguese Hospital: An 11-Year Retrospective Study

BACKGROUND

Chlamydia trachomatis infections remain a burden worldwide. The goals of this study were to determine the number of C.trachomatis infections per year, characterize the demographic traits of the infected population and identify the associated sexually transmitted infections (STI), over the last 11years, in Lisbon main Hospital Centre.

MATERIALS AND METHODS

Laboratorial confirmed C.trachomatis infections diagnosed between January 1st, 2009 and December 31st, 2019 were evaluated.

RESULTS

A total of 6404 samples were collected, with 602 being positive for C.trachomatis, corresponding to 550 patients. 60% of diagnoses were made by dermatovenereologists and most cases occurred in males (n=371; 67.5%), with a median age of 26.1years (standard deviation 7.98), ranging from 13 to 68years. More than half the cases (51.3%) occurred below the age of 25years. In 87 patients (15.8%) there was previous history of STI, in 198 patients (36%) a concomitant STI was present and 43 patients (7.8%) developed a posterior STI. Concerning follow-up, 196 patients (corresponding to 35.6% of total patients) did not show for a re-evaluation after the diagnosis was made.

CONCLUSION

Confirmed cases of C.trachomatis infection have risen along the years, affecting mainly people younger than 25 years. C.trachomatis infection is especially associated with Neisseriagonorrhoeae infection, but other STI are also very prevalent. Considering the potential complications of C.trachomatis infection, screening and treatment are necessary. The high percentage of diagnoses made by dermatovenereologists support the pivotal role of dermatovenereology in diagnosing C.trachomatis infections.