Clinical efficacy of Tailin formulation combined with continuous low-dose antimicrobial therapy for recurrent urinary tract infection: study protocol for a multicenter, double-blind, randomized, controlled clinical trial

BACKGROUND: Given the increasing rates of antimicrobial resistance (AMR), recurrent urinary tract infection (rUTI) is becoming refractory more and more. Antibiotic prophylaxis including continuous low-dose antibiotic therapy (CLAT), is the common treatment for rUTI of the world. However, the presumably adverse reactions caused by CLAT alone should be paid more attention. Studies indicated that Chinese herbal medicine (CHM) might be an available treatment method for rUTI. Tailin formulation (TLF) is a herbal prescription developed for the treatment of rUTI in the 2000s in Shanghai Municipal Hospital of Traditional Chinese Medicine. Our previous studies have shown TLF could prevent urinary tract infection both in pyelonephritis (PN) rat model and in PN patients. Additionally, our published data demonstrated TLF is helpful to reduce the recurrence of rUTI and protect renal tubular function in clinic. In order to find a novel treating project for rUTI to increase the clinical curative effect, we thus try to combine TLF with CLAT to treat rUTI and design an optimized, pragmatically clinical trial to evaluate the efficacy and safety of this project. METHODS/DESIGN: This is a multicenter, double-blind, randomized, controlled clinical trial. We will enroll 200 eligible patients diagnosed with uncomplicated rUTI and then divide them randomly into two groups with a 1:1 ratio: TLF + CLAT group and placebo + CLAT group. This trial consists of two stages, a 12-week period of treatment and a 12-week period of post-treatment follow-up, respectively. The primary outcome will be the recurrence rate at the 12th week of the follow-up period; the second outcomes will be the post-treatment changes in renal and liver function; furthermore, traditional Chinese medicine (TCM) symptoms, non-infection-related physical signs, and subjective symptoms will be scored, and the number of episodes of each subject will be also recorded; meanwhile, vital signs indicators and serious adverse events (SAEs) will be monitored throughout the trial. DISCUSSION: This study will provide convictive research-derived data to evaluate clinical efficacy and safety of TLF combined with CLAT for rUTI, and provide an evidence-based recommendation for clinicians. Moreover, post-treatment changes in non-infection-related physical signs and subjective symptoms were included in the efficacy evaluation, which is important and more significant for assessing the clinical benefits for those rUTI patients. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100041914. Registered on 10 January 2021. Protocol date and version: September 12, 2020; version 1. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-021-05830-4.