Upswing of Syphilis in Women With HIV

SEATTLE -- Prior intravenous drug use and hepatitis C infection were tied to increased syphilis rates in women with HIV, factors that could help guide screening decisions in this high-risk group, a new study found.

Women with a history of IV drug use had more than twice the likelihood of syphilis infection (adjusted OR 2.3, 95% CI 1.3-3.9), as did those with prior hepatitis C infection (adjusted OR 2.1, 95% CI 1.3-3.7), Jodie Dionne-Odom, MD, of the University of Alabama at Birmingham, reported here.

"There appears to be a strong association between intravenous drug use and hepatitis C infection among women living with HIV infection," Dionne-Odom said during a press conference at the Conference on Retroviruses and Opportunistic Infections (CROI). "Further studies are needed to determine if this association is mediated via transactional sex or high-risk sex partners."

Syphilis rates in the U.S. have been rising since 2012 and are at a 20-year peak, she said, and noted that the study findings dovetailed with CDC research indicating that drug use is driving the epidemic in women.

The retrospective study looked at over 4,000 women with HIV enrolled in the Clinical Network of Integrated Clinical Systems (CNICS) Cohort who were screened for syphilis. Among them, 2.8% tested positive for the sexually transmitted infection, for a rate of 7.6 cases per 1,000 person-years.

"The focus on syphilis in HIV infection has been on men, and particularly men who have sex with men, but these studies on women are important because there have been more than 900 cases of congenital syphilis in 2018, and we need to know which interventions to do that will impact those rates," Dionne-Odom said. "These predictors are important to understand so we can come up with interventions to try to reduce the problem."

She noted that screening is one way, as syphilis is treatable and testing is relatively easy in the U.S., but that currently there are no recommendations as to when and how often to perform screening. "We have a ways to go to define how often we need to be looking, particularly in high-risk women," she said.

Based on the findings, she said guidelines should prioritize women with HIV and IV drug abuse for syphilis screening and prevention.

"We have rising rates of syphilis in the United States, so finding risk factors for these women and doing more testing and treatment to catch people early is quite important," Susan Buchbinder, MD, of the University of California, San Francisco, told MedPage Today.

"We in San Francisco do testing quarterly for sexually transmitted infections," said Buchbinder, who was not involved in the study, noting that this routine testing is "part of the integration of all pre-exposure prophylactic services."

For their study, Dionne-Odom's group tested 4,416 women (median age 47) from the CNICS cohort for syphilis. About 64% of the women were black, 28% were white, and 8.2% were Hispanic. Roughy three-quarters of women reported that they were infected with HIV through heterosexual sex, while 18% said they were infected through injection drug use and 7% were unaware of how they acquired the infection.

Women in the study had at least one HIV clinic visit from 2005 to 2016. Data were extracted from the electronic medical record and patient reported outcomes were collected every 6 months. Incident syphilis was defined as a newly positive non-treponemal serologic test after a previously negative test or a fourfold increase in titer, both with positive confirmatory testing. The median number of years with visits to clinicians for HIV consultation was 5; the median number of HIV-related visits in a year was 3.

During their most recent year in care, 40.3% of the women said they had no sexual partner, 52.0% said they had one, and 7.2% said they had two or more. About 4% of women said they had more than six sexual partners in the past year. About 52% said they consistently used condoms during intercourse, and 13.7% said they had sex after doing drugs or alcohol.