Chronic inflammation and mortality in haemodialysis: effect of different renal replacement therapies. Results from the RISCAVID study

Background. The 'RISchio CArdiovascolare nei pazienti afferenti all' Area Vasta In Dialisi' (RISCAVID) study is an observational and prospective trial including the whole chronic haemodialysis (HD) population in the northwest part of Tuscany (1.235 million people). The aim of the study was to elucidate the relevance of traditional and non-traditional risk factors of mortality and morbidity in HD patients as well as the impact of different HD modalities. Methods. A total of 757 HD patients (mean age 66 +/- 14 years, mean dialytic age 70 +/- 76 months, diabetes 19%) were prospectively followed up for 30 months and all-cause mortality, cardiovascular (CV) mortality and non-fatal CV events (acute myocardial infarction and stroke) were registered. At the time of the enrolment, demographic, clinical and laboratory data of the whole population were entered into a centralized database. Serum albumin, high-sensitive C-reactive protein (CRP), interleukin-6 (IL-6) and interleukin-8 (IL-8) were centrally determined at the start of the study. Patients were stratified into three groups according to the HD modality: standard bicarbonate HD (BHD) (n = 424), haemodiafiltration (HDF) with sterile bags (n = 204) and online HDF (n = 129). The Cox proportional hazards regression assessed adjusted differences in CV morbidity and mortality risk; a multivariate analysis was also performed. Results. All-cause and CV mortality was 12.9%/year and 5.9%/year, respectively. Patients with combined high levels of CRP and pro-inflammatory cytokines showed an increased risk for CV (RR 1.9, P < 0.001) and all-cause mortality (RR 2.57, P < 0.001). Multivariate analysis adjusted for comorbidity and demographic showed CRP as the most powerful mortality predictor (P < 0.001) followed by IL-6. The Cox proportional hazards regression assessed that online HDF and HDF patients had a significantly increased adjusted cumulative survival than BHD (P < 0.01). Conclusions. Data at 30 months from this study showed the synergic effect of CRP and pro-inflammatory cytokines as the strong predictors of all-cause and CV mortality. HDF was associated with an improved cumulative survival independent of the dialysis dose.