Intestinal flora imbalance has a high prevalence in CKD patients and is closely invloved with CKD complications like malnutrition and anemia, which affects quality of life and long-term prognosis of CKD patients. Probiotics is the bioactive compound produced by probiotics when it consumes prebiotics. It can alleviate the condition and improve quality of life of patients by regulating growth of microbiota directly and indirectly and inhibiting growth of pathogenic microorganism. The purpose of the trial is to explore the effect of exogenous postbiotics supply on the quality of life and nutritional status of elderly hemodialysis patients.

The study is a multicenter prospective open-labled and randomized controlled trial. Elderly patients with age ≥65 years and received hemodialysis treatment for more than 6 months will be included in the study. During the screen period, the patients with medical history that might affect oral feeding or gastrointestinal functions will be excluded.

After enrollment, the patients will be educated about how to keep diet records and then they will be randomly divided into group A (intervention group) and group B (placebo group) in an 1:1 ratio. The patients in group A will receive oral postbiotics and group B receive placebo. The treatment period is 12 weeks. Subsequently, group A ends the trial, and group B enters the remedial treatment period, receiving oral postbiotics, and the treatment cycle is 12 weeks.

At 0, 12 and 24 weeks quality of life score, nutrition evaluation, diet status and gastrointestinal symptom score respectively will be evaluated. The stool and serum of patients will be collected for intestinal flora and urotoxins measurements. Besides, the trial will collect routine biochemical indicators. The investigators will analyze those indicators above from the baseline to end of treatment and compare the difference between intervention group and placebo group.