The Frequent Hemodialysis Network (FHN) Daily Trial is a randomized controlled trial recruiting subjects from dialysis units associated with designated Clinical Centers in the U.S. and Canada and followed for 1 year. Subjects will be randomized to either conventional hemodialysis Daily HD delivered for at least 2.5 hours (typically 3 to 4 hours), 3 days per week, or to more frequent hemodialysis delivered for 1.5 - 2.75 hours, 6 days per week. The study has two co-primary outcomes: 1) a composite of mortality with the change over 12 months in left ventricular mass by magnetic resonance imaging, and 2) a composite of mortality with the change over 12 months in the SF-36 RAND physical health composite (PHC) quality of life scale.
Inclusion Criteria: 1. Patients with end stage renal disease requiring chronic renal replacement therapy 2. Age 13 years or greater 3. Achieved mean eKt/V of \> 1.0 on at least two baseline sessions 4. Weight 30 kg or greater Exclusion Criteria: 1. Residual renal urea clearance \> 3 mL/min per 35 L. 2. Expectation that native kidneys will recover 3. Vascular access being used for HD is a non-tunneled catheter 4. Inability to come for in-center 6 days a week, including inability to arrange adequate transportation 5. History of poor adherence to thrice weekly HD 6. Medical conditions that would prevent the subject from performing the cardiac MRI procedure (e.g., inability to remain still for the procedure, a metallic object in the body, including cardiac pacemaker, inner ear (cochlear) implant, brain aneurysm clips, mechanical heart valves, recently placed artificial joints, and older vascular stents) 7. Unable to verbally communicate in English or Spanish 8. Requires HD \> 3 times per week due to medical co-morbidity (such as, but not limited to: systemic oxalosis, or requiring total parenteral nutrition). Occasional ultrafiltration on a fourth day per week is not an exclusion criterion. 9. Currently on daily or nocturnal HD, or less than 3 months since the subject discontinued daily or nocturnal HD 10. Scheduled for living donor kidney transplant, change to peritoneal dialysis, home HD, or plans to relocate to another center within the next 14 months 11. Expected geographic unavailability at a participating HD unit for \> 2 consecutive weeks or \> 4 weeks total during the next 14 months (excluding unavailability due to hospitalizations) (frequent HD subjects who leave for vacation may resort back to conventional HD during these time periods) 12. Less than 3 months since the patient returned to HD after acute rejection resulting in allograft failure 13. Currently in acute or chronic care hospital 14. Life expectancy \< 6 months 15. A medical history that might limit the subject's ability to take trial treatments for the 12 month duration of the study, including: currently receiving chemo or radiotherapy for a malignant neoplastic disease other than localized non-melanoma skin cancer, active systemic infection (including tuberculosis, disseminated fungal infection, active AIDS but not HIV, and cirrhosis with encephalopathy) 16. Current pregnancy, or actively planning to become pregnant in the next 12 months 17. Contraindication to heparin, including allergy or heparin induced thrombocytopenia 18. Current use of investigational drugs or participation in another clinical trial that contradicts or interferes with the therapies or measured outcomes in this trial 19. Unable or unwilling to follow the study protocol for any reason (including mental incompetence) 20. Unable or unwilling to provide informed consent or sign IRB-approved consent form