LAUSR

Gut microbiome alteration increases uremic toxin levels inducing chronic inflammation and leading morbidity and mortality in patients with chronic kidney disease. Phosphate-binding agents may potentially change the composition of the gut microbiota. However, the limited clinical study investigates the microbiome difference between iron-containing and calcium-containing phosphate binders. The aim of this study was to compare the microbiota composition in hemodialysis patients treated with ferric citrate or calcium carbonate. The stool microbiota was investigated in hemodialysis patients with ferric citrate used (n=8) and calcium carbonate used (n=46) by 16S rRNA next-generation gene sequencing profiling. The altered microbiota between two different phosphate binders was analyzed. Differences in the microbial composition of the two patient groups were assessed using linear discriminant analysis effect size. Hemodialysis patients with calcium carbonate used revealed significantly reduced microbial species diversity (Shannon index and Simpson index) and increased microbial dysbiosis index compared with ferric citrate users. Compared to patients taking calcium carbonate, a distinct microbial community structure in patients taking ferric citrate, with an increased abundance of Bacteroidetes phylum and decreased abundance of phylum Firmicutes. In comparison between two phosphate binder users, members of the order Lactobacillales were prominent in calcium carbonate therapy, including family Streptococcaceae and genus Streptococcus. In contrast, taxa of the genus Ruminococcaceae, Flavonifractor, and Cronobacter were enriched in ferric citrate phosphate binder users. The fecal microbiota was richer and more diverse in the ferric citrate group than in the calcium carbonate group. Hemodialysis patients with ferric citrate used were associated with differences in the gut microbiome composition compared to calcium carbonate users.