Chronic inflammation is widely diffuse in maintenance haemodialysis (HD) patients and is associated with poor survival. Middilution (MID) is a novel dialytic technique that could improve inflammatory status by increasing convective clearance . However this topic is unknown. The aim of this prospective cross-over study was to compare the effect of an higher to a lower convection rate on inflammatory biomarkers in HD patients.
After a 1 month run-in period of bicarbonate dialysis, chronic HD patients were shifted with a cross-over design to a higher convection treatment by Middilution (MID) or a lower convection treatment by post-dilution hemodiafiltration (HDF). Each study period of 4 months was followed by 1 month of HD and the total duration of the study was 9 months. Primary outcome was the change of serum C reactive Protein (CRP), IL-6, IL-1, IL-10, TGF-β, TNF-α, β2-Microglobulin, albumin and prealbumin, monthly assessed, during four months of each treatment. Repeated Measures ANOVA or Friedman test was performed according the distribution of each parameter.
Ten HD patients were enrolled (age:64.9±12.6 years; dialytic vintage: 10.6(2.7-16.2) years; 70% males). Mean convection volume was 40.6±2.6 L/session (of which 26.5±1.7 L/session in post-dilution) in MID and 16.8±2.1 L/session in HDF. In MID we registered a reduction of CRP from 11.3 [3.2-31.0] to 3.1[1.4-14.4] mg/L (P=0.007), IL-6 from 12.7 [5.0-29.7] to 8.3 [4.4-14.0] pg/mL (P=0.003), TGF-β from 10.6[7.4-15.6] to 7.4[5.9-9.3] ng/mL (P=0.001) and β2-Microglobulin from 39.0±9.4 to 30.1±9.1 mg/L (P<0.0001). In HDF a significant reduction of CRP from 8.5 [3.2-31.0] to 4.6 [3.2-31.0] mg/L (p=0.037) and β2-Microglobulin from 39.4±9.3 to 30.1±9.1 mg/L was detected (P<0.0001). In MID the percentage changes of serum CRP and IL-6 were correlated with post-dilutional convective volume [R=0.73 (P=0.018) and R=0.71 (P=0.022) respectively].
MID is associated with an attenuation of inflammatory pattern that seems to be correlated with higher convective volume.
