Multidose Metronidazole Treatment for Trichomonas vaginalis More Effective Than Single-Dose Treatment in Clinical Practice: A Retrospective Cohort Study.

BACKGROUND

Trichomonas vaginalis (TV) is the most prevalent nonviral sexually transmitted infection globally. The objective of this study was to estimate the effectiveness of multidose metronidazole treatment on repeat TV test positivity in pregnant and nonpregnant women.

METHODS

This retrospective cohort study used electronic medical record data and included patients testing positive for TV by nucleic acid amplification test between July 2020 and June 2022 at a large safety-net hospital in the Southeast United States. The primary exposure was treatment type (no treatment, single-dose metronidazole, and multidose metronidazole), and the outcome was a repeat positive TV test between 4 and 20 wk after the initial test. Covariates included demographic characteristics, substance use, pregnancy, and concurrent sexually transmitted infection. Log-binomial regression modeling estimated the association between treatment type and repeat positive TV test.

RESULTS

Of 1583 women with a positive TV test during the study period, 66% were under the age of 35 y, 96% self-identified as Black, and 39% were pregnant. Only 487 women (31%) had a repeat test performed and 26% of these (n = 125) had TV on repeat testing. Compared with multidose treatment, both no treatment and single-dose treatment were associated with a higher risk of repeat positive TV test (relative risk: 2.43; 95% confidence interval: 1.48-4.01 and relative risk: 1.44; 95% CI: 1.05-1.99, respectively).

CONCLUSIONS

Repeat test rates were low and repeat TV positivity was high. Multidose metronidazole was superior to single-dose treatment. Strategies to increase repeat testing and address high repeat positivity should be undertaken in routine clinical settings.