Background: In a randomized controlled trial of 2 g (single-dose) metronidazole (MTZ) versus 500 mg twice daily for 7 days (multidose) for Trichomonas vaginalis treatment, multidose was superior. We examined if the effect was similar by select clinical factors to determine if treatment recommendations could be targeted.
Methods: The primary outcome was T. vaginalis repeat infection at test-of-cure (TOC) 4 weeks after completion of therapy. Analyses were stratified by T. vaginalis history, baseline genital symptoms, and concurrent diagnosis of bacterial vaginosis (BV) per Nugent score at baseline.
Results: Women who returned for TOC (n = 540) were included. At baseline, 52.9% had a self-reported history of T. vaginalis; 79.3%, genital symptoms; 5.8%, a gonorrhea diagnosis; and 47.5%, BV. During follow-up, 97.4% took all MTZ as instructed and 34.5% had interval condomless sex with a baseline partner. At TOC, 14.8% tested positive for T. vaginalis. In stratified analysis, women randomized to single-dose MTZ had a higher rate of TOC T. vaginalis positivity than those randomized to multidose if they were symptomatic at baseline (21.4% vs. 10.8%, P = 0.003) or had a reported history of T. vaginalis (24.1% vs. 12.6%, P = 0.01). Test-of-cure T. vaginalis positivity was higher for women receiving a single dose (18.9%) versus multidose (10.8%), irrespective of baseline BV status (P > 0.06). In multivariable analysis, only a history of T. vaginalis and single-dose MTZ were independently associated with a positive TOC for T. vaginalis.
Conclusions: Although multidose MTZ is recommended for all women with T. vaginalis, it is especially important for women with a T. vaginalis history and, given high posttreatment infection rates, a TOC should be performed.
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