Biological and behavioral factors associated with positive chlamydia retests

Kirsty S Smith, Rebecca Guy, Jennifer A Danielewski, Sepehr N Tabrizi, Christopher K. Fairley, Anna M McNulty, William Rawlinson, Marion Saville, Basil Donovan, John Martin Kaldor, Jane S. Hocking, on behalf of the REACT investigators

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Background: Repeat chlamydia detection after treatment is common, and there is concern that treatment failure may be a cause. Methods: Within a randomized trial, we established a prospective cohort of 600 participants with anogenital chlamydia diagnoses (200 each of women, heterosexual men, and men who have sex with men [MSM]). Participants were invited for repeat testing at 3 months and to complete a behavioral survey at 4 months. Positive samples were analyzed for organism DNA load and genovar. We estimated repeat chlamydia positivity, reinfection and treatment failure rates, and investigated the biological and behavioral factors associated with a repeat positive test. Results: A total of 290 participants (100 women, 89 heterosexual men, 101 MSM) were retested at 1 to 4 months, with 43 repeat positives, including 26 classed as reinfection and 9 as treatment failures. Comparing MSM with heterosexual men and women combined, repeat positivity was higher (20.8% vs 11.6%, P = 0.04), and treatment failure was higher (6.9% vs 1.1%, P = 0.01), but there was no difference in reinfection rates (11.9% vs 7.4%, P = 0.21). Among MSM, the odds of repeat positivity increased by 90% with each additional log organism load in the original specimen (baseline) (adjusted odds ratio, 1.9; 95% confidence interval, 1.1-3.2). Among heterosexuals, the odds of repeat positivity decreased by 10% with each additional week delay in being retested for chlamydia (adjusted odds ratio, 0.9; 95% confidence interval, 0.8-0.9). Conclusions: Positive retests were more common among MSM than heterosexuals. Treatment failure was more common in MSM with rectal chlamydia, reinforcing concerns about azithromycin treatment failure.

Original languageEnglish
Pages (from-to)417-422
Number of pages6
JournalSexually Transmitted Diseases
Issue number7
Publication statusPublished - 2017

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