Weight Changes in Fecal Microbiota Transplant for Clostridium difficile

Abstract Background Fecal microbiota transplant (FMT) for relapsing Clostridium difficile infections (CDI) allows for rapid repopulation of the colonic microbiome and may prevent future relapses. FMT is considered safe, however subsequent impact on weight and metabolism are incompletely understood. Animal studies have shown that alterations in microbiota lead to changes in weight; this is also suggested in humans, based on limited anecdotal evidence. This study explores changes in weight associated with FMT. Methods We conducted a retrospective observational study of patients who underwent FMT at our 1100-bed community-based academic healthcare system. FMT protocol requires 2 documented CDI relapses and failed vancomycin taper. FMT methods include colonoscopy, EGD and oral capsules. Of note, donor stool (OpenBiome, Boston, Massachusetts) criteria include BMI 5% gain 11 (65) >10% gain 6 (35) >5% loss 6 (50) >10% loss 2 (17) Average % of body weight change (among those with changes) - Gain 7.7 Loss 5.5 Conclusion In this limited population, it appears FMT may predispose to weight gain, which may reflect improved health with CDI cure. However, effects of FMT on patient’s microbiomes must also be considered. As this intervention becomes more widely used we must be increasingly aware of possible metabolic side effects and ensure documentation of weight changes as part of FMT protocols. Disclosures All authors: No reported disclosures.