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Short report
STIs in sex partners notified for chlamydia exposure: implications for expedited partner therapy
  1. Fleur van Aar1,
  2. Birgit H B van Benthem1,
  3. Ingrid V F van den Broek1,
  4. Hannelore M Götz1,2
  1. 1 Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
  2. 2 Department of Infectious Disease Control, Municipal Public Health Service, Rotterdam, the Netherlands
  1. Correspondence to Fleur van Aar, National Institute for Public Health and the Environment, PO Box 1, 3720BA, Bilthoven, the Netherlands; fleur.van.aar{at}rivm.nl

Abstract

Objectives Expedited partner therapy (EPT) may reduce chlamydia reinfection rates. However, the disadvantages of EPT for chlamydia include missing the opportunity to test for other STIs and unnecessary use of antibiotics among non-infected partners. As part of a larger study that investigated the feasibility of EPT in the Netherlands, we explored the frequency of STI among a potential EPT target population of chlamydia-notified heterosexual men and women attending STI clinics for testing.

Methods Cross-sectional national STI/HIV surveillance data, which contain information on all consultations at STI clinics, were used to calculate STI positivity rates stratified by chlamydia notification and gender, and proportions of STI that were attributable to clients notified for chlamydia.

Results Of all consultations in 2015 (n=101 710), 14 445 (14.4%) clients reported to be notified exclusively for chlamydia. Among chlamydia-notified clients, the chlamydia positivity rate was 34.2% (n=4947), and consequently 65.8% (n=9488) of them tested negative for chlamydia. Chlamydia-notified clients contributed to 10.2% of all gonorrhoea infections (n=174/1702) and 10.9% of all infectious syphilis, HIV and/or infectious hepatitis B infections (n=15/173).

Conclusion Implementing EPT without additional STI testing for all partners of chlamydia-infected index patients implies that STIs other than chlamydia will be missed. Although the chlamydia positivity rate was high among chlamydia-notified partners, two-thirds would unnecessarily use azithromycin. An evaluation of EPT against the current partner treatment strategy is needed to carefully weigh the potential health gains against the potential health losses and to explore the characteristics of EPT-eligible partners.

  • chlamydia trachomatis
  • partner notification
  • gonorrhoea
  • infection control
  • surveillance
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Introduction

Treatment of sex partners is an important strategy for chlamydia control. The Dutch STI clinics provide traditional partner notification (PN) for STIs.1 As chlamydia is highly prevalent, and PN via STI clinic physicians (provider referral) is time-consuming, the majority of the index clients notify their sexual contacts themselves (patient referral). Besides, patients may prefer patient referral over provider referral.2 Persons who attend the STI clinic because of a chlamydia notification receive STI testing similar to other patients. However, the partner management guidelines allow immediate treatment before test results are available to prevent reinfection if the STI notification is verified, or when the client was notified by a current (steady) partner or had recent (<2 months) sexual contact with the index patient.3 Still, recurrent chlamydia infections are common among STI clinic clients.4

Expedited partner therapy (EPT) includes alternative approaches to partner management, such as patient-delivered partner therapy, which aims to reduce barriers to STI testing and treatment for the index patients’ partners. Therefore, EPT may increase the number of partners notified and treated.5 Moreover, EPT may reduce chlamydia reinfection rates by decreasing the time between the treatment of index patients and their partners. The ultimate goal is to reduce chlamydia incidence at the population level, but this effect has not yet been established.6 Although EPT might have beneficial effects, there are concerns about the missed opportunity to screen a high-risk population for STI other than chlamydia, assuming that the population reached by EPT would also be reached by traditional patient referral. In addition, uninfected sexual contacts of index patients could unnecessarily receive antibiotic treatment (azithromycin).7

We explored the legitimacy of the EPT concerns as part of a larger study that investigated the feasibility of EPT implementation in the Netherlands (Patient Initiated Contact treatment for Chlamydia: Understanding the Potential for increased effectiveness of Partner treatment in the Netherlands (PICC-UP)). Men who have sex with men were excluded in the PICC-UP studies because of high risk for STI/HIV coinfections.8 The aim of the current study was to gain insight into the frequency of STI in a potential target population for EPT at STI clinics: heterosexual men and women who reported to be notified for chlamydia exposure.

Methods

We used national STI/HIV surveillance data from 2015, which contained routinely collected data from all STI clinics in the Netherlands.8 STI clinics provide low-threshold STI/HIV testing and care, which is free of charge and targeted at high-risk groups. During consultation, clinicians collected information on demographic variables, sexual risk behaviour, STI/HIV history, STI testing and diagnosis. A selection of information registered in the electronic patient records was sent to the national STI clinic surveillance database. Notifications for STIs by sex partners were routinely registered, including for which STI clients were notified.

We used the PN data to create a dichotomous outcome: clients notified exclusively for chlamydia exposure versus all other clients, which include persons who were notified for other STI (either with or without chlamydia) and clients who were not notified. These categories were chosen because EPT would only be an option if the index patient is diagnosed with chlamydia only, but not if coinfected with other STIs. The number and positivity rates of STIs were explored for heterosexual men (men who had sex with women only) and women (both heterosexual and lesbian) stratified by STI notification. In addition, the proportions of other STIs (gonorrhoea, syphilis, HIV and/or hepatitis B) that were attributable to clients who were notified for chlamydia exposure were calculated.

Results

Study population

In 2015, 35 719 consultations among heterosexual men and 65 991 consultations among women were reported (table 1). In general, the STI clinic visitors were at high risk of having an STI; for example, of all clients, 35.4% reported STI-related symptoms, 26.0% originated from an STI endemic country (including Turkey and all countries in Africa, Asia, Eastern Europe and Latin America), and 47.5% reported having had more than three sex partners in the past 6 months. In addition, in 20 250 (19.9%) consultations, the client reported to be notified for an STI. The majority of the clients were notified exclusively for chlamydia (n=14 445; 71.3% of all STI notifications).

Table 1

Number and percentage of consultations, chlamydia-notified clients and STI among heterosexual men and women attending STI clinics in the Netherlands in 2015

STI diagnoses by STI notification

One-third of all chlamydia infections were among clients who were notified exclusively for chlamydia (4937/15 105; 32.7%; table 1), among whom the chlamydia positivity rate was 34.2% (heterosexual men: 32.4%; women: 35.9%). Conversely, 65.8% of the chlamydia-notified clients tested negative for chlamydia. The chlamydia positivity rate was lower among clients who received other STI notifications or who were not notified (11.7%).

In total, 669 heterosexual men and 1033 women were diagnosed with gonorrhoea (table 1). One out of ten gonorrhoea infections (174/1702; 10.2%) was diagnosed among clients notified exclusively for chlamydia. Of these, 92 (52.9%) were coinfected with chlamydia. Among chlamydia-notified clients, 1.2% (heterosexual men: 0.8%; women: 1.6%) tested positive for gonorrhoea.

In total, 15 infectious syphilis, HIV or infectious hepatitis B infections were diagnosed among heterosexual men and women notified exclusively for chlamydia. Of these, seven had a concomitant chlamydia infection. Looking at the characteristics of these clients in more detail showed that 13 out of these 15 clients were first-generation immigrants from STI/HIV endemic countries.

Discussion

PN is an important tool for chlamydia control, as we found a high chlamydia positivity rate among chlamydia-notified clients. Still, two-thirds of the chlamydia-notified clients tested negative for chlamydia, while other STIs were not uncommon: chlamydia-notified clients contributed to one out of ten gonorrhoea diagnoses among heterosexual male and female STI clinic clients within a year, and one infectious syphilis and two HIV infections were found. This indicates that EPT for chlamydia for all partners in this setting can result in overtreatment and missed diagnosis of other STIs, especially gonorrhoea.

Our results are limited to a high-risk population attending STI clinics and cannot be generalised to other settings in which STIs are diagnosed (eg, general practices). Another limitation is that the results concern a population already visiting the STI clinic after an STI notification. In this group, EPT may lead to missed infections. However, EPT may also facilitate treating partners at high risk of a chlamydia infection who would otherwise not be reached by traditional PN and/or would not seek STI testing. Thus, EPT may also lead to more chlamydia infections treated that would not have been tested anyway. Unfortunately, the frequency of no-show after PN has not yet been investigated in the Netherlands. Last, PN practices are often based on self-report; hence, explanations for discordance between the reported STI notification and diagnosis include, in addition to STI acquisition from different partners, incomplete PN by the index patient or incorrect PN information provided by the notified client.

Enhanced approaches to the current chlamydia test-and-treat prevention strategy, such as EPT, are needed to decrease the chlamydia (re)infection rate. However, determining the feasibility of EPT implementation is complex as there is no clear cut-off point at which the balance between EPT benefits and risks remains positive. A previous study found high chlamydia rates and relatively low rates of other STIs in partners of index patients, and therefore concluded that EPT benefits might outweigh the disadvantages.9 We found a slightly lower chlamydia positivity rate and a considerable number of gonorrhoea infections among chlamydia-notified clients. One could argue that our benefit–risk balance is unfavourable.

Another concern of EPT is overtreatment with antibiotics, especially since many efforts are done to decrease unnecessary use of antibiotics and thereby to slow down the development of antimicrobial resistance. Although azithromycin resistance has not yet been documented in Chlamydia trachomatis, the resistance in gonococci is increasing in the Netherlands and internationally.8 10 To prevent antibiotic overuse, direct partner treatment is only advised for the current and most recent (ex-)partners according to guidelines.3 With these restrictions we expect higher chlamydia positivity rates than presented in the current study (34.2%), but unnecessary use of antibiotics may still occur. Unfortunately, the characteristics of the index patients who referred their partners were not included for routine surveillance and could not be explored.

If EPT methods are going to be developed, we recommend to offer chlamydia and gonorrhoea (home) testing in addition to treatment in order to detect gonorrhoea (co)infections and to enable PN for the partners’ sex partners. Second, according to our results, EPT should not be recommended for sex partners with a migration background from STI/HIV endemic regions. A pilot study would be needed to explore the willingness to accept home testing and treatment among partners and the ability of index patients to provide accurate information on the risk profile of their partners.

In conclusion, EPT without further STI testing for all sexual contacts of chlamydia-infected index patients could lead to both missed diagnoses of STIs other than chlamydia and overtreatment with antibiotics. However, an evaluation of EPT against the current partner treatment strategy is needed to carefully weigh the potential health gains of EPT against the potential health losses and to explore the characteristics of EPT-eligible partners.

Acknowledgments

We would like to thank all nurses and physicians of the STI clinics for their contribution to data collection.

References

View Abstract

Footnotes

  • Handling editor Katy M E Turner

  • Contributors FA coordinated the national STI clinic data collection, analysed and interpreted the data, and drafted the manuscript. HMG was the leader of the PICC-UP project. All other authors were involved in the data interpretation and contributed to drafting and revision of the paper. All authors read and approved the final manuscript.

  • Funding This work was part of a larger project ‘Patient Initiated Contact treatment for Chlamydia: Understanding the Potential for increased effectiveness of Partner treatment in the Netherlands’ (PICC-UP), which was supported by the Netherlands Organisation for Health Research and Development (ZonMw) (grant number: 522002001).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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