Medium Cut-Off and High-Flux Membranes on Mineral and Bone Metabolism in Hemodialysis Patients

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication in patients receiving maintenance hemodialysis and is associated with abnormalities in mineral metabolism, bone turnover, vascular calcification, and increased cardiovascular risk. Biomarkers such as fibroblast growth factor-23 (FGF-23) and sclerostin play important roles in the pathophysiology of CKD-MBD and have been associated with adverse clinical outcomes in patients with end-stage kidney disease. Medium cut-off (MCO) hemodialysis membranes have been developed to enhance the removal of middle-molecular-weight uremic toxins compared with conventional high-flux membranes. Because FGF-23 and sclerostin are relatively large circulating molecules, MCO membranes may provide improved clearance and potentially influence CKD-MBD-related biological pathways. This study is a single-center, prospective, randomized, open-label, two-sequence, two-period crossover clinical investigation conducted in maintenance hemodialysis patients. Eligible participants will be randomized in a 1:1 ratio to one of two treatment sequences. Sequence A will receive MCO hemodialysis for three months followed by high-flux hemodialysis for three months. Sequence B will receive high-flux hemodialysis for three months followed by MCO hemodialysis for three months. Assessments will be performed at baseline, Month 3, and Month 6. Primary outcome measures include changes in serum FGF-23 and sclerostin concentrations. Secondary outcome measures include changes in pulse wave velocity (PWV), body composition parameters measured by BCM, handgrip strength, health-related quality of life (KDQOL-36), pruritus severity (UP-Dial), and pain characteristics (SF-MPQ). Routine laboratory evaluations will be performed according to standard clinical practice. In addition, blood samples will be collected for FGF-23 and sclerostin measurements at each study visit. Safety assessments will include monitoring of adverse events, dialysis-related intolerance, and clinically significant medical events throughout the study period. The results of this study are expected to provide evidence regarding the effects of MCO membranes on CKD-MBD-related biomarkers and patient-centered outcomes and may contribute to optimizing membrane selection strategies in maintenance hemodialysis practice.