Fecal Short and Branched Chain Acids as Possible Biomarkers for Inflammatory Bowel Disease and UC and CD Subgroups? A Case-Control Study

Goals: Investigate feasibility of short (SCFA) and branched chain fatty acids (BCFA) in human stool as biomarkers for inflammatory bowel disease (IBD). Background: Interest in fecal SCFAs and BCFAs has increased. Evidence shows strong connections between these metabolites and IBD pathogenesis and pathophysiology. Study: A case-control study of 74 stool samples (21 healthy; 24 ulcerative colitis, UC; 29 Crohn?s disease, CD) was quantified using a validated, gas chromatography-mass spectrometry (GC-MS) method for acetic, propionic, isobutyric, butyric, isovaleric, valeric, and caproic acid (?g/g stool). Bristol Stool Form Scale (BSFS) and pH were recorded. Results: Receiver operator curve (ROC) analysis resulted in area under the curve (AUC) value of 0.96 (95% CI: 0.89-0.98, P<0.001), with 92% sensitivity and 81% specificity using the acetic/(propionic+butyric+isovaleric+valeric acid) transformation between healthy and IBD groups. ROC analysis resulted in AUC of 0.83 (95% CI: 0.66-0.92, P<0.001), with 75% sensitivity and 86% specificity using the acetic/(isobutyric/propionic acid) transformation between UC and CD subgroups. Acetic acid was the most abundant SCFA (72/74 samples) and nonsignificantly different between groups (healthy vs. IBD; P?0.05, 0.161 and UC vs. CD; P?0.025, 0.623). Conclusions: Fecal SCFAs and BCFAs demonstrated feasibility as biomarkers for IBD. Increased sensitivity and specificity were achieved over fecal calprotectin (FCP) tests between healthy and IBD patients. No useable data was found in the literature to use a validation cohort