Risk factors and characteristics of gut microbiota and metabolites in inflammatory bowel diseases patients with urolithiasis

Abstract

Objective: To identify the related factors and characteristics of gut microbiota and metabolites in inflammatory bowel disease (IBD) patients with urolithiasis. Methods: A total of 68 IBD patients with urolithiasis and 136 gender-and age-matched IBD patients without urolithiasis in the Department of Gastroenterology, Peking Union Medical College Hospital from January 2014 to December 2019 were recruited. The diagnosis of urolithiasis was confirmed by plain films, ultrasonography, abdominal computed tomography or intravenous urography. The clinical data of patients were collected, and the association between the clinical characteristics and urolithiasis was further analyzed. The fecal samples were collected from 10 patients with urolithiasis and 18 patients without urolithiasis, and the gut microbiota and metabolites composition were analyzed. Results: There were 49 male and 19 female IBD patients with urolithiasis, with a mean age of (36.0±12.4) years, and 98 male and 38 female patients without urolithiasis, with a mean age of (36.1±12.5) years. Univariate analysis revealed that the rate of ileostomy and the resection of small intestine in Crohn's disease (CD) patients with urolithiasis (n=34) was significantly higher than CD patients without urolithiasis (n=68) (26.5% vs 7.4%, P=0.019). And the erythrocyte sedimentation rate was also higher [26.5 (12.0, 40.8) vs 13.0 (7.2, 32.5) mm/1 h, P=0.022] in CD patients with urolithiasis. There were no significant differences in clinical characteristics and biochemical parameters between the ulcerative colitis (UC) patients with urolithiasis (n=34) and without urolithiasis (n=68) (all P>0.05). The multivariate logistic regression analysis indicated that ileostomy and the resection of small intestine were the independent related factors for urolithiasis in CD patients (OR=4.619, 95%CI: 1.178-18.111, P=0.028). There was no significant difference in α and β diversity between the two groups (all P>0.05). At the phylum level, there was no significant difference in the abundance of microbiota (all P>0.05). At the genus level, the abundance of Enterococcus (P=0.049), Eubacterium_eligens (P=0.036) was significantly decreased. At the species level, the abundance of Bacteroides_coprocola was increased in urolithiasis group (P=0.035), while the abundance of Blautia_caecimuris was significantly decreased (P=0.042). No significant difference was found in fecal metabolites between the two groups (all P>0.05). According to LDA effect size (Lefse) analysis, taxa including Sphingomonadales, Fenollaria, Bacteroides_coprocola contributed greatly to the difference between the two groups. Conclusions: Ileostomy and the resection of small intestine are related factors for urolithiasis in patients with CD. Gut microbiota may be involved in the occurrence of urolithiasis in patients with IBD.