Patients are randomly assigned to 1 of 4 groups: moderate dose dialysis, low flux membrane; high dose dialysis, low flux membrane; moderate dose dialysis, high flux membrane; or high dose dialysis, high flux membrane. Moderate dose is a target eKt/V of 1.05 and high dose is 1.45. The dose and delivery of dialysis are measured monthly by the equilibrated fractional clearance of urea (eKt/V) calculated with double pool kinetics.