Study Treatment, Dosage, and Route of Administration: Enrolled patients have been randomized in 2 groups: 15 patients continued high flux bicarbonate hemodialysis (BHD), whereas 15 patients switched to mixed on-line hemodiafiltration (mOL-HDF using FX 1000 CorDiax, Fresenius Medical Care, Bad Homburg, Germany) for 9 months.