Statistical analysis
SE, bacterial vaginosis
REGRESSION, SECONDARY, BACTERIAL VAGINOSIS
Assuming that 80% of participants receiving metronidazole would achieve symptom resolution [All analyses were performed using Stata® SE 15.1 (StataCorp LP, College Station, TX, USA) according to the Statistical Analysis Plan (SAP) which was finalised without knowledge of treatment allocation and prior to database lock.The primary approach to between-group comparative analysis included all participants who were randomised and analysed according to randomised treatment group without imputation of missing outcome data. Pre-specified sensitivity analyses of the primary outcome were conducted to investigate the impact of missing data, additional baseline variables and adherence to allocated treatment.Evaluation of the primary outcome planned to use a mixed-effects model for binary outcome including minimisation factors and whether the participant had performed vaginal douching in the 3 months prior to randomisation. However, due to model non-convergence, a generalised estimating equation for binary outcomes was applied including minimisation factors (excluding type of site since only one general practice recruited participants), and site as a panel variable and excluding whether the participant had performed vaginal douching. The adjusted odds ratio was presented in addition to the planned adjusted risk difference and adjusted risk ratio to allow for consistency in presentation with the sensitivity analyses which used a random effects logit model instead of the planned mixed-effects model, due to non-convergence issues. These changes to the proposed models were documented in the SAP.Most secondary outcomes were analysed using appropriate regression models including minimisation factors (except site type) and outcome baseline value where measured. Side effect data were summarised using counts and proportions, according to the treatment the participant actually received, irrespective of allocation.Pre-planned exploratory sub-group analyses were conducted to investigate whether there was an interaction affecting the primary outcome between treatment group and whether bacterial vaginosis had been confirmed by positive microscopy at baseline, presence of a concomitant STI, number of episodes of bacterial vaginosis in the 12 months before randomisation and total time with bacterial vaginosis in the 12 months before randomisation. These latter two sub-groups were inadvertently not stated in the published protocol but were included in the SAP.The study and its reporting adhered to all CONSORT guidelines.