4. Discussion
DISEASE, COMPLICATIONS
Despite the increasing evidence that gut microbiota are important in health and disease, the association between alteration of gut microbiota and bowel preparation for colonoscopy is underinvestigated. The results of the present study provide evidence for the beneficial effects of probiotic pretreatment on the alteration and recovery of the gut microbiome and possible complications after colonoscopy.Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body [In a randomized controlled trial in which the effects of preoperative bowel preparation were evaluated in patients undergoing colorectal surgery, a significant reduction was observed in the total number of bacteria [The strength of the present study was the randomized, double-blind, placebo-controlled trial design in which the beneficial effects of probiotic pretreatment on the gut microbiota and the complications after bowel preparation for colonoscopy were investigated. The present study also had several limitations. First, the number of participants in this study was small. At the start of this study, we wanted to enroll 100 participants based on a previous study; however, this was not possible likely due to the age restriction which was not applied in the previous study. Interim analysis was performed after collecting feces from 32 participants and the data were nearly similar to the data from 51 participants. Similar results were expected even if the number of participants was increased; therefore, we considered that 51 participants were sufficient for analysis. Second, the mean age of participants in this study was relatively young (53.7 ± 1.1 years) compared to the average age of people undergoing bowel preparation for colonoscopy. We set the age of participants to 40–65 years to limit the age factor from acting as a variable, although it should be considered that complications are more prevalent in older people. Third, the association between the specific gut microbiota and the occurrence of complications after colonoscopy was not evaluated. Further studies are needed to confirm the results of this study. Fourth, this trial included only Korean participants and was conducted in a single institution. Therefore, the results may not be directly generalized to populations of other institutions and countries.