Impact of changes in chlamydia treatment guidelines on recurrent/persistent rectal Chlamydia trachomatis infections

Abstract Introduction Prior to 2021, the US Centers for Disease Control and Prevention (CDC) recommended either doxycycline or azithromycin as first-line treatments for Chlamydia trachomatis. By 2016, there was evidence showing that doxycycline was more effective than azithromycin for the treatment of rectal CT. This motivated the Public Health – Seattle & King County Sexual Health Clinic (PHSKC SHC) to update their clinic’s protocol to treat rectal CT with exclusively doxycycline in mid-2016. The CDC later recommended this in July 2021. Methods Leveraging health records from the clinic, we performed a controlled interrupted time series analysis to evaluate the impact of updated treatment guidelines at the clinic on recurrent/persistent rectal chlamydia (RP-CT) infections among men who have sex with men using recurrent/persistent rectal gonorrhea as a control outcome. We also evaluated if there were patient demographic and behavioral correlates associated with receipt of azithromycin before and after the change in clinic guidelines. Results Our analysis revealed a significant relative trend change between RP-CT and RP-GC when comparing the period of full implementation to pre-implementation, showing a 16.9% greater reduction in the quarterly trend of RP-CT cases compared to RP-GC cases. Self-identifying as White and living with HIV were positively associated with receiving azithromycin for treatment of rectal CT after the change in guidelines. Conclusions The significant reduction in the trend change for RP-CT vs. RP-GC when comparing the fully implemented period of exclusively doxycycline to the pre-implementation period demonstrates the impact of the new treatment guidelines in reducing incidence of RP-CT infections.