comparison of post- and pre-dilutional hemodiafiltration in hemodialysis patients

Conditions: Hemodiafiltration

Summary: hemodiafiltration (hdf) is a choice of treatment modalities for patients with end-stage renal disease. hemodiafiltration, combining diffusion and convection, may increase removal of large and middle molecule uremic toxins comparing to conventional hemodialysis. the techniques of hemodiafiltration include pre-dilution and post-dilution according to the infusion site of substitution fluid. post-dilution hdf is most widely used because of higher removal rate of uremic toxins. however, hemoconcentration and clotting of membrane limit its further clearance of toxins. pre-dilution may preserve membrane permeability and maintain hemodynamic status. although lower clearance of small molecule uremic toxins, one study in japan showed survival benefits of pre-dilution hdf, comparing to post-dilution hdf. the aim of this study was to compare pre-dilution and post-dilution hdf in terms of their clinical and biological parameters and clearance of uremic toxins by using cross-over study design.

1. study design: randomly assigned, cross-over study. 2. patient number: 60. 3. inclusion criteria: stable patients end-stage renal disease who were older than 20 years and received thrice-weekly standard hemodialysis for more than 3 months were recruited. 4. exclusion criteria: active systemic disease, liver cirrhosis, active malignancy, receiving immunosuppressive treatment, dialysis with temporal non-tunneled catheter, inadequate dialysis dose (single-pooled kt/v\<1.2). 5. methods: prior to randomization, a charlson comorbidity index score and baseline characteristics are recorded for each patient. each patient who received hdf prior to study will received one-month high-flux hemodialysis with target single-pooled kt/v\>1.2 for washout. the baseline characteristics of each patient including dialyzer, dialysis time, blood flow, dialysate flow, replacement volume, pre- and post-dialysis blood pressure and body weight were recorded. the follow-up laboratory data will also be collected: predialysis c-reactive protein, blood urea nitrogen, creatinine, bicarbonate, sodium, potassium, uric acid, albumin, calcium, phosphate, intact parathyroid hormone, β2-microglobulin, prolactin, fibroblast growth factor 23, α1-microglobulin, indoxyl sulfate, p-cresol sulfate, advance oxidation protein products, advance glycation product, percentage of proinflammatory monocytes; interleukin-6, tumor necrosis factor-α, hematocrit, transferrin saturation and ferritin. urea kinetics including kt/v, urea reduction ratio and normalized protein catabolic rate are calculated. we also used physical symptoms distress scale for life quality measurement. after randomization, two group received standard prescription of pre- and post-dilution hdf. the prescribed convective volume per treatment of post-dilution mode is based on blood flow, filtration fraction and hematocrit to achieved current recommendation of 23 liter/1.73m2. the convective volume of pre-dilution mode will be at least twice higher than the desired dose in post-dilution mode for each patient. after 3-month stable hemodiafiltration, parameters mentioned above will also be checked. two group will be switched for another 3-month course and then switch again. the total following time is 12 months. 6. outcome: the primary objective is to compare the removal of a wide spectrum of solutes such as middle and protein-bound molecules. secondary outcomes are intradialytic tolerance, including intradialytic hypotension, cramps and arrhythmia, and life quality measurements.

Eligibility criteria:
inclusion criteria: * stable patients end-stage renal disease who were older than 20 years and received thrice-weekly standard hemodialysis for more than 3 months were recruited. exclusion criteria: * active systemic disease, liver cirrhosis, malignancy, receiving immunosuppressive treatment, dialysis with temporal non-tunneled catheter, inadequate dialysis dose (kt/v\<1.2).

Keywords: hemodiafiltration pre-dilution post-dilution uremic toxins