Background
Online haemodiafiltration (OL-HDF is associated with increased convective clearance compared to HD, even with a high flux membrane. The aim of this study was to compare the effect of OL-HDF and high-flux HD  (HF-HD) on anemia, metabolic bone disease markers and dialysis efficiency. Patients and Methods
 In this prospective study, 16 children, on hemodialysis for at least three months, were shifted from HF-HD to OL-HDF for a period of 3 months on each modality. The mean age of patients was 10.31 ± 3.28 years, and the mean duration on HD was 57.50 ± 38.24 months. Blood pressure, hemoglobin (Hb), Calcium, phosphorus and Parathyroid hormone were measured after 3 months of HF-HD and again after 3 months of OL-HDF. Results
In our study, dialysis efficiency expressed by Kt/V was significantly improved by OL-HDF (2.07±0.47) as compared to HF-HD (1.75±0.46); p value of 0.006. Significantly lower levels of Phosphorus and Parathyroid hormone (PTH) on HF-HD compared to OL-HDF were observed (4.25 ±1.3 to 4.92 ±1.9 mg/dl on OL-HDF, p value 0.04; and 404±476 to 749±79 g/dl, p value 0.001, respectively). The levels of Hb, hematocrit (HCT) and ferritin, Erythropoietin dose requirements were not significantly differnet. Systolic blood pressure values showed significant reduction on HF-HD (111.4 ±12.3 and 114.4 ±10.9 mmHg respectively, p value 0.013). Conclusions
Over a period of three months, oHDF was not associated with better anemia management and nutrition when compared to HF-HD, while HDF proved to be more beneficial in dialysis efficiency. HF-HD was more effective in controlling BP and metabolic bone disease.