Lactic acid gel versus metronidazole for recurrent bacterial vaginosis in women aged 16 years and over: the VITA RCT

Results: Recruitment stopped prior to reaching the target of 1900 participants on recommendation from the Data Monitoring Committee and Trial Steering Committee after a planned review of the results indicated that the research question had been answered. Overall, 518 participants were randomised and primary outcome data were available for 409 participants (79%; 204 in the metronidazole arm, 205 in the lactic acid gel arm). Participant-reported symptom resolution at week 2 was higher with metronidazole (143/204; 70%) than with lactic acid gel (97/205; 47%) (adjusted risk difference -23.2%, 95% confidence interval -32.3% to -14.0%). Recurrence in 6 months in a subset of participants who had initial resolution and were available for follow-up was similar across arms (metronidazole arm: 51/72, 71%; lactic acid gel arm: 32/46, 70%). A higher incidence of some side effects was reported with metronidazole than with lactic acid gel (nausea 32% vs. 8%; taste changes 18% vs. 1%; diarrhoea 20% vs. 6%, respectively). At week 2, the average cost per participant with resolved symptoms was 86.94 pound (metronidazole), compared with 147.00 pound (lactic acid gel). Some participants preferred using lactic acid gel even if they perceived it to be less effective than metronidazole. Limitations: Loss to follow-up for collection of the primary outcome data was 21% and was similar in both arms. There is a risk of bias owing to missing outcome data at 3 and 6 months post treatment. Conclusions: A higher initial response was seen with metronidazole than with lactic acid gel, but subsequent treatment failure was common with both. Lactic acid gel was less cost-effective than metronidazole. In general, women disliked taking repeated courses of metronidazole and preferred lactic acid gel, even when they were aware that it was less likely to provide symptom resolution. In the absence of effective curative therapy, further evaluation of non-antibiotic treatments to control the symptoms of recurrent bacterial vaginosis is required to improve quality of life for these patients. Further microbiological analysis of vaginal samples would be useful to identify additional factors affecting response to treatment. Trial registration: Current Controlled Trials ISRCTN14161293. Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 2. See the NIHR Journals Library website for further project information.