Clinical evaluation of the efficacy and safety of nasturtium herb and horseradish root versus placebo in the continuous prophylaxis of recurrent uncomplicated cystitis: a double-blind randomised clinical trial

This study aimed to demonstrate the efficacy and safety of a herbal combination drug of nasturtium herb and horseradish root in the continuous prophylaxis of recurring uncomplicated cystitis. The clinical trial was conducted as a phase III, two-armed, placebo-controlled, randomised, double-blind, prospective, and multi-center study, which followed a parallel-group design in Germany. Data were collected in a multicenter setup in Germany. Patients of either sex aged ≥ 18 years with recurring uncomplicated cystitis were considered for the study. Interventions were Nasturtium herb and horseradish root prophylaxis versus placebo. The primary outcome measure was the rate of first recurrent urinary tract infection (rUTI) observed during six months of recurrence prophylaxis in the herbal and the placebo group from day 0 to day 180. Additional efficacy outcome measures included: recurrence rates at scheduled visits during the course of recurrence prophylaxis; recurrence rates during three- and six-month follow-up and Investigator’s assessment of efficacy at completion of recurrence prophylaxis. Safety evaluation included type, frequency, and severity of reported adverse events. A total of 224 patients were enrolled, of which 217 women were included in the full analysis set. Patients were randomised to treatment with either nasturtium herb and horseradish root (N = 110) or placebo (N = 107). The cumulative recurrence rate increased for the placebo group to approximately 40% by day 90 and 48% by day 180, while the nasturtium herb and horseradish root group had lower rates of 26% and 36%, respectively. The overall risk of rUTI was reduced by 36% (hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.42–0.97, p = 0.0327) in the treatment group. This effect remained consistent (although statistically insignificant) during the follow-up period up to 360 days. There were no significant differences between groups, for any of the reported adverse effects. The results of this study indicate that nasturtium herb and horseradish root may be an effective, safe prophylactic treatment for female patients suffering from rUTIs. This trial was registered with EudraCT under the number: EudraCT 2013-004653-25. The study was approved on 2nd of May 2014 and the first participant was enrolled on 9th of May 2014.