Many rectal STIs in women missed by genital testing only

Testing women for the presence of sexually transmitted infections (STIs) only at the urogenital site will miss approximately 20% of STIs in women who report having receptive anal intercourse, a STD surveillance network study indicates.
“As an obstetrician-gynecologist, I thought it would be interesting to analyse data from women who report having receptive anal intercourse and see what the rates of chlamydia and gonorrhea might be,” Eloisa Llata, MD, MPH, Centers for Disease Control and Prevention, Atlanta, Georgia, said in podcast prepared by the journal, Obstetrics & Gynecology.
“We found that about one in five women who reported having receptive anal intercourse will only be infected at the rectal site, so if we only screen women with a urine-based approach, we are going to miss these women and the opportunity to stop transmission,” she added.
“So this study underscores the need to ascertain a comprehensive sexual history for all patients, male and female, in order to identify risky behaviours and to test accordingly,” Llata emphasized.
The researchers collected and analysed data from the STD Surveillance Network involving 10 state and local health jurisdictions for all visits between January 2015 and December 2016.
The researchers included 94,094 visits made to STD clinics in five jurisdictions in the analysis.
A total of 7.4% of women presenting for care during a 2-year interlude reported having receptive anal intercourse.
Some 94.1% of women were tested for Chlamydia trachomatis at the urogenital site, whereas 94.5% were tested for Neisseria gonorrhea at the same site.
Fewer women, at 76.9%, were tested for the same two STIs at the rectal site.
C trachomatis positivity was 9.1%, and N gonorrhea positivity was 5.4% among women tested only at the genital site.
Results differed among women who were tested only at the rectal site. In this subgroup of women, C trachomatis was detected in 26.7% of samples and N gonorrhea in 6.1% of them.
Investigators then identified infection rates for each of the two STIs separately in women who were tested at both the genital and rectal sites.
Analysis of this subgroup of women found that 10.4% of women tested positive for C trachomatis; of these, 20.9% of women were positive for the infection at the genital site only, whereas 58.6% of women tested positive at both the genital and rectal sites.
Another 20.5% of women were positive for C trachomatis only at the rectal site.
For women who were tested at both the genital and rectal site for N gonorrhea, 4.5% of women had been infected with the STI.