Background: In chronic hemodialysis (HD) patients, the repetitive induction of the acute phase response (APR) may induce a chronic micro-inflammatory state, leading to various long-term complications.
Methods: The present prospective study was designed to assess the alterations in the APR in 74 patients who were randomized to HD with a high-flux polysulfone (PS; F 60S), a super-flux PS (F 500S), or a super-flux cellulosic tri-acetate (CTA and CTA with filtered dialysate, CTA(f)) dialyzer. Blood samples collected at the start of the study and after twelve weeks were analyzed for interleukin-6 (IL-6) and C-reactive protein (CRP). In addition to the microbiological quality of the dialysate, the appearance of a "clinical event" was assessed.
Results: At baseline, mean IL-6 levels were within the reference range whereas mean CRP levels were slightly elevated. Mean values did not change after 12 weeks of HD with either modality. After subdividing the patients in quartiles with increasing change in plasma CRP, 23.0% of the patients showed a change of more than 8.0 mg/L. In a multiple regression analysis, CRP levels appeared to be independent of the degree of dialysate contamination, the material and the flux characteristics of the devices. In fact, the variable "clinical events" was the only significant predictor of the plasma CRP levels (P < 0.001).
Conclusions: Based on these results, both PS and CTA super-flux dialyzers appear safe for clinical use. Whether changes in CRP values, which are associated with intercurrent clinical events, influence the long-term prognosis of chronic HD patients remains to be established.