This study aims to compare the effects of medium cut-off (MCO) and high-flux hemodialysis membranes on mineral and bone metabolism biomarkers in patients receiving maintenance hemodialysis. Chronic kidney disease-mineral and bone disorder (CKD-MBD) is characterized by disturbances in biomarkers such as fibroblast growth factor-23 (FGF-23) and sclerostin, which are associated with bone turnover, vascular calcification, and adverse clinical outcomes.

This is a single-center, prospective, randomized, open-label, two-sequence, two-period crossover clinical study. Thirty adult patients receiving maintenance hemodialysis will be randomized to receive either MCO membrane treatment followed by high-flux membrane treatment or the reverse sequence, with each treatment period lasting three months.

Serum FGF-23 and sclerostin levels will be measured at baseline, Month 3, and Month 6. Additional assessments will include pulse wave velocity (PWV), body composition monitoring (BCM), handgrip strength, health-related quality of life (KDQOL-36), pruritus severity (UP-Dial), and pain assessment (SF-MPQ). The study will evaluate whether MCO membranes provide additional benefits compared with conventional high-flux membranes regarding CKD-MBD-related biomarkers and patient-centered outcomes.

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.

Inclusion Criteria:

• Age 18 to 80 years.
• Receiving maintenance hemodialysis for at least 6 months.
• Clinically stable and receiving thrice-weekly hemodialysis.
• Able to comply with study procedures, questionnaires, and scheduled assessments.
• Able and willing to provide written informed consent.

Exclusion Criteria:

• Acute infection at screening or enrollment.
• Major surgery within the previous 3 months.
• Active malignancy requiring ongoing treatment.
• Terminal illness with limited life expectancy.
• Physical or cognitive impairment preventing completion of study procedures or questionnaires.
• Inability or unwillingness to provide written informed consent.

Individual participant data (IPD) are not planned to be shared publicly. The study involves a limited number of participants from a single center, and data will be retained and managed in accordance with institutional policies, ethical requirements, and applicable data protection regulations.

This is an open-label study. Participants, care providers, and investigators are aware of the assigned dialysis membrane. No masking procedures are planned.