Solutions to Reduce Unnecessary Imaging-Reply.

bic chamber at only 1 center, making it impossible to process autologous FMT stool anaerobically at each trial site. We believe, however, that the risk of bias from this is minimal. Autologous stool samples were processed at room temperature and frozen within minutes of laboratory delivery. Therefore, there was not sufficient time, nor optimized growth conditions, for significant proliferation of oxygentolerant organisms, such as Enterobacteriaceae, during processing. While the relative proportion of oxygen-tolerant, potentially pathogenic bacteria was likely to be higher following aerobic processing, the overall number of such organisms would not likely have been increased. Although the autologous stool may have been devoid of some beneficial organisms due to aerobic processing, this would not have introduced significantly increased numbers of pathogens and thus should not have significantly reduced the placebo response. Of course, much of this explanation is supposition based on best evidence available, and the answer can only be clarified with a randomized clinical trial comparing anaerobic and aerobic donor FMT groups. It is not clear that steroids potentiate the effect of donor FMT because there are no human trials powered to assess this. Benech and colleagues cite data from a murine model in support of this notion.3 Post hoc analyses from 2 previous randomized FMT studies in humans with ulcerative colitis demonstrated no effect of steroid therapy on remission.4,5 Paramsothy et al4 reported that 0 of 9 patients in the donor FMT group who entered the trial while taking steroids achieved remission. Conversely, in the post hoc logistical regression analysis in our study, oral steroids were associated with a greater reduction in total Mayo score following donor FMT. Therefore, the data from human trials are inconsistent on this question. It is also unclear whether the length of time receiving steroid therapy prior to enrollment would influence any putative effect. The patients entering our trial taking steroid therapy underwent a mandatory steroid taper, which would have diminished any late steroid effect as steroid therapy ongoing at week 8 was considered therapeutic failure. In addition, only a minority of patients entered the study receiving steroid therapy, and there was no statistical difference between the number of patients taking steroids in the donor FMT and autologous FMT groups (8/38 [21%] vs 11/35 [31%]; odds ratio, 0.67 [95% CI, 0.23-1.80]; P = .61). Therefore, any differences in steroid therapy duration prior to enrollment are unlikely to have significantly influenced the rate of remission overall.