What Is the Optimal Time to Retest Patients With a Urogenital Chlamydia Infection? A Randomized Controlled Trial

BACKGROUND Chlamydia trachomatis is a common, often recurring sexually transmitted infection, with serious adverse outcomes in women. Current guidelines recommend retesting after a chlamydia infection, but the optimum timing is unknown. We assessed the optimal retest interval after urogenital chlamydia treatment. METHODS A randomized controlled trial among urogenital chlamydia nucleic acid amplification test positive heterosexual clients of the Amsterdam sexually transmitted infection clinic. After treatment, patients were randomly assigned for retesting 8, 16, or 26 weeks later. Patients could choose to do this at home (and send a self-collected sample by mail) or at the clinic. Retest uptake and chlamydia positivity at follow-up were calculated. RESULTS Between May 2012 and March 2013, 2253 patients were included (45% men; median age, 23 years; interquartile range, 21-26). The overall uptake proportion within 35 weeks after the initial visit was significantly higher in the 8-week group (77%) compared with the 16- and 26-week groups (67% and 64%, respectively, P < 0.001), and the positivity proportions among those retested were comparable (P = 0.169). The proportion of people with a diagnosed recurrent chlamydia infection among all randomized was similar between the groups (n = 69 [8.6%], n = 52 [7.4%], and n = 69 [9.3%]; P = 0.4). CONCLUSIONS Patients with a recent urogenital chlamydia are at high risk of recurrence of chlamydia and retesting them is an effective way of detecting chlamydia cases. We recommend inviting patients for a re-test 8 weeks after the initial diagnosis and treatment.