LAUSR

Four RCTs have been published that compared on-line HDF (Ol-HDF) with HD. However, to date, an indisputable answer in determining whether patients treated with Ol-HDF had a better survival than those treated with high-flux HD (Hf-HD) has not been reached. The aim of our study was to retrospectively evaluate the impact of the dialysis modality (Hf-HD, Ol-HDF or acetate-free biofiltration AFB) on patient survival and dialysis adequacy. We retrospectively evaluated all the incident patients that started dialysis due to uremia from 01-01-2008 to 31-12-2018 at the U.O. Nephrology ASST Spedali Civili of Brescia. Exclusion criteria were: duration of dialysis treatment less than 3 months, and previous dialytic treatment or kidney transplantation. The dialysis modality performed (Hf-HD vs Ol-HDF), the modality of infusion (pre-dilution or post-dilution) and mean total convective volume (replacement fluid volume + ultrafiltration) during last year’s dialysis session in Ol-HDF were analyzed for each patient. During observation 677 patients started HD treatment. 70 patients were excluded due to less than 3 months HD treatment. 607 patients (male 390, 64%) were analyzed. 467 pts (77%) were treated with Hf-HD, 103 pts (17%) with Ol-HDF, 36 pts (6%) with AFB. Median duration of HD treatment was 2.6 years (IQR 1.3; 4.7). Ol-HDF was performed in post-dilution mode in 60% of cases (total convective volume 25±4 L); pre-dilution mode was used in 40% of the cases (total convective volume 51±18 L). Patients in the Ol-HDF group were significantly younger than those in Hf-HD and AFB groups (respectively 59±15 years vs 71±15 vs 78±9, p <0.05), and had less diabetes, hypertension and ischemic heart disease (p<0.05) while presenting similar prevalence of cirrhosis (p=0.93) and peripheral vascular disease (p=0.09). Adequacy indices were similar between groups (eKt/V 1.39±0.02 vs 1.41±0.01 vs 1.44±0.04, p=0.47) as well as the protein intake (PCRn 0.92±0.01 vs 0.93±0.01 vs 0.90±0.03 g/Kg/d, p=0.69) and residual renal function (1.5±0.3 vs 1.6±0.1 vs 0.8±0.4 ml/min, p=0.20). Patients on Ol-HDF more frequently had an AV fistula (71% vs 58% vs 59%, p<0.05). At the end of follow-up, 12% of patients had undergone kidney transplantation, 42% continued dialytic treatment while 43% died. Univariate analysis showed a better survival for Ol-HDF patients (Figure 1) (p <0.05). This benefit was confirmed in multivariate analysis (Figure 2) showing that older age, cirrhosis and ischemic heart disease negatively affect survival, while a high protein intake, use of an AV fistula and Ol-HDF (HR 0.43[0.30-0.61]) are protective. The use of Ol-HDF is associated with better survival compared to Hf-HD. This is confirmed after adjustment for demographic and comorbidities of the patients, characterizing Ol-HDF as an independent predictor of better survival.