Behavioural and medical predictors of bacterial vaginosis recurrence among female sex workers: longitudinal analysis from a randomized controlled trial

BACKGROUND: Data on risk factors of recurrent bacterial vaginosis (RBV) are still scarce. We used data from female sex workers (FSW) participating in a randomized controlled microbicide trial to examine predictors of BV recurrence. METHODS: Trial’s participants with at least an episode of BV which was treated and/or followed by a negative BV result and at least one subsequent visit offering BV testing were included in the analysis. Behavioural and medical data were collected monthly while laboratory testing for STI and genital tract infections were performed quarterly. The Andersen-Gill proportional hazards model was used to determine predictors of BV recurrence both in bivariate and multivariate analyses. RESULTS: 440 women were included and the incidence rate for RBV was 20.8 recurrences/100 person-months (95% confidence interval (CI) =18.1–23.4). In the multivariate analysis controlling for the study site, recent vaginal cleansing as reported at baseline with adjusted hazard-ratio (aHR)=1.30, 95% CI = 1.02-1.64 increased the risk of BV recurrence, whereas consistent condom use (CCU) with the primary partner (aHR=0.68, 95% CI=0.49-0.93) and vaginal candidiasis (aHR=0.70, 95% CI=0.53-0.93), both treated as time-dependent variables, were associated with decreased risk of RBV. CONCLUSION: This study confirms the importance of counselling high-risk women with RBV about the adverse effects of vaginal cleansing and the protective effects of condom use with all types of partners for the prevention of sexually transmitted infections, including BV. More prospective studies on risk factors of BV recurrence are warranted. TRIAL REGISTRATION: Trial registration: NCT00153777