Methodology quality appraisal

Quality assessment of each RCT and cohort study was carried out by two authors independently and disagreements were resolved by discussion. The methodological quality of two RCTs was assessed using the Cochrane risk of bias tool.[27] For the one-arm cohort studies, quality was assessed by the adjusted Newcastle-Ottawa Scale on the following criteria: representativeness of the UC cohort, ascertainment of FMT, demonstration that outcome of interest was not present at start of study, assessment of outcome, the length (at least 3months) and adequacy of follow-up. [28, 29] It should be noted that we considered “demonstration that outcome of interest was not present at start of study” as “evidence of no prior FMT exposure”.