BackgroundHypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHIs) have improved the treatment of renal anemia, especially in patients resistant to erythropoiesis-stimulating agents (ESAs). HIF facilitates maintain gut microbiota homeostasis, which plays an important role in inflammation and iron metabolism, which are in turn key factors affecting ESA resistance. The current study aimed to investigate the effects of roxadustat on inflammation and iron metabolism and on the gut microbiota in patients with ESA resistance.MethodsWe conducted a self-controlled, single-center study including 30 patients with ESA resistance undergoing maintenance hemodialysis. All patients received roxadustat without iron agents for renal anemia. Hemoglobin and inflammatory factors were monitored. Fecal samples were collected before and after 3 months’ administration and the gut microbiota were analyzed by 16S ribosomal RNA gene sequencing.ResultsHemoglobin levels increased after treatment with roxadustat for 3 months (P< 0.05). Gut microbiota diversity and abundance also changed, with increases in short-chain fatty acid (SCFA)-producing bacteria (Acidaminococcaceae, Butyricicoccus,Ruminococcus bicirculans,Ruminococcus bromii,Bifidobacterium dentium,Eubacterium hallii) (P< 0.05). Serum SCFA levels also increased (P< 0.05). Inflammatory factors, including interleukin (IL)-1, IL-6, tumor necrosis factor (TNF)-α, interferon-γ, and endotoxin gradually decreased (P< 0.05). Serum hepcidin, ferritin, and total and unsaturated iron-binding capacities decreased (P< 0.05), while soluble transferrin receptor levels increased at each time point (P< 0.05). There were no significant differences in serum iron and transferrin saturation at each time point. The abundance ofAlistipes shahiiwas significantly negatively correlated with IL-6 and TNF-α (P< 0.05).ConclusionsRoxadustat alleviated renal anemia in patients with ESA resistance by decreasing inflammatory factors and hepcidin levels and improving iron utilization. These effects were at least partly mediated by improved diversity and abundance of SCFA-producing gut bacteria, probably via activation of HIF.