Friday, January 16, 2015

Uptake and Population-Level Impact of Expedited Partner Therapy (EPT) on Chlamydia trachomatis and Neisseria gonorrhoeae

Plos: Every day, more than 1 million people worldwide acquire a sexually transmitted infection (STI). STIs are viral, bacterial, or parasitic infections that pass between people during sexual activity (through semen, vaginal fluids, blood, or skin-to-skin contact). Two of the most common STIs—chlamydia and gonorrhea—are caused by bacteria (Chlamydia trachomatis and Neisseria gonorrhoeae, respectively).
Chlamydia rarely has any symptoms, especially in women, although some infected individuals experience pain when urinating or a discharge from the penis or vagina. The typical symptoms of gonorrhea (“the clap”) include a thick green or yellow discharge from the vagina or penis and pain when urinating, but about 10% of infected men and half of infected women have no symptoms. Both these STIs are diagnosed by testing a urine sample or a genital swab and can be treated with antibiotics. If left untreated, both infections can spread to other parts of the body and cause serious health problems including pelvic inflammatory disease (infection of the internal reproductive organs) and infertility in women.

Why Was This Study Done?

Condom use during sex reduces the risk of getting or passing on chlamydia or gonorrhea, but additional approaches are needed to reduce the incidence (the number of new cases in a population in a year) of these STIs. One promising approach is expedited partner therapy (EPT)—treating the sex partners of people with a curable STI without requiring the partners to undergo a medical evaluation. EPT usually involves clinicians giving their patients antibiotics to give to their sex partners (patient-delivered partner therapy, or PDPT). Although clinical trials of EPT have shown that the approach increases partner treatment and decreases gonorrhea and chlamydia reinfection rates, EPT has not been widely adopted in the US. In this stepped-wedge, community-level randomized trial, the researchers test whether a public health program can increase the population-level use of EPT and decrease the prevalence of chlamydial infection (the proportion of a population that has chlamydia) and the incidence of gonorrhea in women. A stepped-wedge randomized trial sequentially and randomly rolls out an intervention to groups (clusters) of people and compares outcomes both between groups and within groups before and after the intervention.

What Did the Researchers Do and Find?

The researchers randomly assigned local health jurisdictions in Washington State, US, to one of four study groups. The intervention, which was instituted sequentially by the groups at intervals of 6–8 months, included the provision of free PDPT packs for clinicians to hand to their patients and the provision of partner services—public health department staff offered patients free PDPT to treat up to three partners and offered to contact the partners of patients who did not want to notify their partners personally about their STI. During the 22-month trial, the intervention increased the proportion of patients receiving PDPT from clinicians from 18% to 34% and the proportion of patients receiving partner services from 25% to 45%. Chlamydia test positivity among young women attending clinics established to screen for chlamydia and gonorrhea as part of US infertility prevention efforts (sentinel clinics) decreased from 8.2% to 6.5%. The incidence of reported gonorrhea among women in the state (gonorrhea infrequently infects women in Washington State, so the researchers needed to look at a larger population than women attending sentinel clinics to get reliable figures for their analysis) decreased from 59.6 per 100,000 to 26.4 per 100,000. After adjusting for temporal trends (changes in the incidence of STIs over time unrelated to the intervention) and running appropriate statistical models, the researchers estimated that the intervention was associated with an approximately 10% reduction in chlamydia positivity and gonorrhea incidence, although these results were statistically insignificant and may therefore be chance findings.

What Do These Findings Mean?

Some aspects of this trial may limit the accuracy and robustness of its findings. For example, during the study period, there was an increase in partner services outside the trial that might have contributed to the observed decreases in STIs and decreased the study’s ability to find an effect associated with the study intervention. Nevertheless, these findings show that the implementation of a public health program promoting the provision of free PDPT substantially increased PDPT use by clinicians in Washington State. Moreover, although the trial did not definitively show that EPT decreased chlamydia test positivity or the incidence of gonorrhea, substantial population-level declines in both STIs occurred concurrently with the introduction of the intervention. The researchers conclude that the continued use and expansion of EPT as a way to reduce the incidence of chlamydia and gonorrhea is warranted, and suggest that the public health intervention used in this trial provides a model for health departments seeking to increase EPT use.

Additional Information.

Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1​001777.
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