Variation of clinical and laboratory features in chronic dialysis patients treated with high-flux hemodialysis after switching to online hemodiafiltration.

PURPOSE: The study of online hemodiafiltration (HDF) benefits over high-flux hemodialysis (HD) raises great interest. The purpose was to compare clinical and laboratory parameters in patients treated with HD who were switched to HDF.

METHODS: Forty-eight HD patients (study group) were switched to HDF, while other 521 patients remained on HD as a control group. During last 6 HD months and during first year of HDF, we determined in both groups the following parameters: monthly-weekly dialysis time, systolic and diastolic blood pressure, body mass index (BMI), interdialytic body weight gain (IBWG), blood flow rate (Qb), weekly erythropoietin-stimulating agents dose (EPO), single-pool Kt/V, calcium, phosphorus (P), hemoglobin and normalized protein catabolic ration (nPCR), plus every 3 months--albumin, parathormone (PTH), ferritin and transferrin saturation (TSAT). In both groups, parameters in the last 6 HD months were compared to those in the first 6 months and, respectively, to those in the first year of HDF.

RESULTS: In the study group, albumin and nPCR were significantly higher in the HD period not only compared to the first 6 months of HDF, but also compared to the first year of HDF. IBWG and P were higher with HD compared to the first year of HDF, but not with the first 6 months. PTH, Kt/V, Qb and EPO were higher in both HDF periods. In the control group, albumin was significantly higher in the first 6 months after the switch, but it was significantly lower in the first year. BMI, ferritin, PTH, Kt/V, Qb, TSAT and weekly dialysis time were higher in both HDF periods, while nPCR, EPO, SBP and DBP were lower. IBWG and Hb rose only during the first year after the switch, while P was lower in the first year, but not in the first 6 months.

CONCLUSIONS: Nutrition, assessed by albumin, nPCR and BMI, was not improved by HDF compared to HD. With HDF, Kt/V and phosphorus control were better, similar results were observed in the control group. A larger EPO dose was needed with HDF for maintaining a similar hemoglobin level.