Effect of Lactobacillus plantarum P9 on defecation, quality of life and gut microbiome in individuals with chronic diarrhoea: Protocol for a randomized, double-blind, placebo-controlled clinical trial.

Background: Probiotics may be an ideal choice for these patients, given it can improve the defecation and quality of life of individuals with chronic diarrhoea. However, evidence-based medical research is still limited to support its use as a diarrhoea agent. Method: A randomized, double-blind, placebo-controlled clinical trial is designed to pinpoint the efficiency and possible action modes of probiotics for chronic diarrhoea. 200 eligible volunteers with chronic diarrhoea are randomly assigned to a probiotic group (orally taking Lactobacillus plantarum p9 probiotics powder) or a placebo group. Except an independent project administrator who will be responsible for unblinding, the other researchers are blinded. Primary outcome is diarrhoea severity score, and secondary outcomes include weekly mean frequency of defecation, weekly mean stool appearance score, weekly mean stool urgency score, emotional state score, gut microbiome, and faecal metabolome. Each outcome measure will be assessed at the timepoints of pre-administration (day 0), administration (day 14 and/or 28), and post-administration (day 42) to identity inter- and intra-groups differences. Adverse events will be recorded to evaluate the safety of L. plantarum p9. Discussion: The study protocol will provide high-quality evidence for the use of probiotics as a diarrhoea agent when it is strictly conducted out, providing evidence regarding whether and to what extent L. plantarum p9 can improve the defecation and well-being of individuals with chronic diarrhoea. Trial registration: Chinese Clinical Trial Registry (ChiCTR) (NO. ChiCTR2000038410). Registered on November 22, 2020, https://www.chictr.org.cn/showproj.aspx?proj=56542.