From the *Sydney Sexual Health Centre/Sydney and Sydney Eye Hospital, Sydney, Australia; and †School of Public Health and Community Medicine, University of New South Wales, Kensington, Australia
Correspondence: Dr Anna McNulty, MBBS, Sydney Sexual Health Centre, GPO 1614, Sydney 2000, Australia. E-mail: firstname.lastname@example.org.
Received for publication January 17, 2008, and accepted March 21, 2008.
Reinfection of index patients by untreated sexual partners accounts for a significant proportion of incident bacterial sexually transmissible infections. The most widely practiced method of partner notification, whereby the index case contacts known sexual partners, results in relatively few sexual partners presenting for assessment.1 Alternative strategies that have been proposed to enhance conventional partner notification include patient delivered partner therapy (PDPT). PDPT requires the index case to give their contacts the treatment for the STI without the contact having to access a clinical service. This strategy has been shown to reduce the rate of reinfection in the index patient for gonorrhea and chlamydia.2–5 However, a limitation of this approach is that concurrent STIs in the contacts may remain undiagnosed and untreated. In addition, because there is no clinical interaction with a health care worker, there is no opportunity to identify other secondary contacts. To examine the extent to which these issues are relevant in an Australian urban sexual health clinic setting, we decided to investigate the concurrent STIs diagnosed in those who present as potential contacts of chlamydia and the number of other sexual partners who are identified.
Sydney Sexual Health Centre is the major public sexually transmissible infections clinic for inner and eastern Sydney, Australia with between 15,000 and 17,000 patient attendances per year. The reason for presentation to the clinic is collected at each visit and entered into the clinic database. For the study period June 2003 until June 2006, the medical records of all those who presented as a contact of chlamydia, non-gonococcal urethritis (NGU), and pelvic inflammatory disease (PID) were extracted. Those who presented as contacts of more than one bacterial STI or HIV were excluded from the study. Clinic policy states that all those who present as sexual contacts of an STI are tested for other bacterial STI and HIV infection; however, this study did not determine the proportion of individuals who had each test performed. The files were reviewed for demographic information, sexual behavior data, and diagnoses of chlamydia infection, newly diagnosed HIV infection, infectious syphilis, gonococcal infection, and Trichomonas vaginalis infection. Only diagnoses that occurred as a consequence of the visit for assessment as a sexual contact of chlamydia were included. Contacts of gonorrhea were excluded in this study as no oral therapy for gonorrhea is available in Australia. For heterosexual patients who proved to have chlamydia, data were collected on whether other secondary contacts within the preceding 6 months were contactable and whether it was documented that they were successfully contact traced. It was not possible to determine from the medical record whether the secondary contacts were assessed or treated. Data were entered in an Excel spreadsheet. Descriptive statistics and Fisher exact test were applied to determine significance.
Ethics approval was obtained for the study from South Eastern Sydney and Illawarra Area Health Service Ethics Committee.
There were 626 contacts eligible for the study, 195 women and 431 men. Of the men, 188 (43.6%) were men who had sex with men. Of the total study population, 466 (74.4%) were contacts of chlamydial infection, 121 (19.3%) were contacts of NGU, and 39 (0.6%) were contacts of PID. Of the total, 199 (31.8%) tested positive for Chlamydia trachomatis by PCR.
Of the 438 heterosexuals, there were few diagnoses of chlamydial complications or other bacterial STI, though higher rates of other STI diagnoses occurred in men who have sex with men (P <0.0001, Table 1). In heterosexual men, 2 (0.8%) were diagnosed with epididymitis. In women, 8 (4.1%) were diagnosed with PID or another bacterial STI. In MSM, 26 (13.8%) were diagnosed with another bacterial STI or HIV.
Of the heterosexual contacts, 145 (33%) were subsequently diagnosed with chlamydia. Of these 62 (42.8%) identified no other sexual partners where contact tracing was determined to be necessary. Men (n = 33) were no more likely than women (n = 29) to have no other partners to notify (P = 0.23). In the remaining 83 cases where other contacts were identified as likely to be contactable, the mean number of other partners was 1.7, with a median of 2 and a range of 1 to 7. A total of 137 other contacts were identified. Of these cases, in 29 (34.9%) it was documented that these further contacts were notified: in 5 cases attempts by the patient to contact trace were unsuccessful and in the remaining 49 (57.8%) the outcome was not documented in the medical record.
Our findings are similar to those reported by Stekler et al.6 In this study, the files of 8623 individuals who attended as sexual contacts in 4 US STD clinics were reviewed. They found comparable concordance to our study in heterosexual men and women, with PID diagnosed in 3.8% of women and 3.2% of men and women diagnosed with gonorrhea compared with 3.1% and 1.0%, respectively, in our study. In men who had sex with men they found 6.3% of those presenting as contacts were newly diagnosed with HIV infection, which is similar to our rate of 5.3%. In addition 6.1% of men who have sex with men presenting as chlamydia contacts had gonorrhea compared with 8.0% in our study.
In a study conducted in an US STD clinic population of young, high risk heterosexuals in partnerships, Khan et al.7 found that among those who were contacts of Chlamydia trachomatis only, 6% had gonorrhea and 11% had trichomoniasis.
In the Australian context, the only study to look at concurrent diagnoses in those seen as contacts of STIs was conducted in the Kimberley region of north western Australia among a remote, predominantly Aboriginal population. In this study, Mak et al.8 found that 36% of those seen as chlamydia contacts had gonorrhea and 5% had syphilis. However, this population is not comparable with an urban sexual health clinic population. In Australia, there are low rates of bacterial STI and HIV diagnosed in urban heterosexual populations.9
In our study, further potentially contactable sexual partners were identified by 57% of those contacts who were diagnosed with chlamydia. In a Melbourne study10 of patients presenting to the clinic, 77% of those who were diagnosed with an STI said that they would be able to contact partners in the preceding 4 to 6 months. Our lower figure is comparable with this; as in our study, the study population were contacts and therefore one of their sexual partners had already been treated thus reducing the proportion of presenting contacts who would have further contacts.
We identified 137 secondary contacts in our study. Australian data11,12 on the success of patient initiated partner notification suggest that only 28% to 29% of these contacts, that is, 21 people, would present. It is likely that between 18.6% and 49.1% of these would test positive for chlamydia.11 Patient delivered partner therapy to the index case may therefore miss the opportunity to identify between 4 (2.9%) and 10 (7.3%) individuals in our study who are contacts of contacts and who have chlamydia and need treatment.
Our study is limited by its retrospective design and the reliance on medical record review. We were unable to confirm the diagnosis in the index case of those who were referred as contacts. It is likely that a number of individuals were not contacts of chlamydia at all and explains why only 31.8% of the contacts subsequently proved to have chlamydia. This is toward the lower end of the range in the studies done on concordance between sexual partners for chlamydia.13,14 Our estimates of coinfection may be underestimates as it is possible that not all patients were tested for all STIs. The quality of the medical record information on contact tracing was quite variable as there are no standard fields in the medical record on this question. Data are not routinely collected at our clinic on the number of sexual partners in the last 6 months, which is the recommended period for contact tracing for C trachomatis in Australia.15 Therefore, we had to infer from the record the likely number of other sexual partners who would need to be contact traced.
Our study does however demonstrate that PDPT would be a worthwhile strategy to consider particularly in heterosexual male partners in urban settings. It could not be recommended for use in men who have sex with men because of the missed opportunity to diagnose other STIs and HIV infection. Others have demonstrated that PDPT leads to an increase in the number of partners treated16 therefore the small number of secondary contacts that are missed would potentially be offset by the increased number of partners treated via PDPT. Although concern exists that the complications of untreated chlamydia may be missed in situations where PDPT is used; it is also plausible that complications would be prevented through access to early treatment via PDPT. Future research should focus on interventions to encourage those who use PDPT to also access clinical services.
The legal status of this option should be investigated and strategies developed to facilitate its implementation in Australian states and territories.
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