Supplementary Material for: Long-term impact of peritoneal dialysis ultrafiltration on cardiorenal patients

Background: Heart failure (HF) prevalence is increasing, and its prognosis worsens in the presence of other comorbidities. Up to 70% of patients develop cardio-renal syndrome (CRS), which is associated with diuretic resistance or kidney deterioration over time. Peritoneal dialysis (PD) for ultrafiltration (PD-UF) could be a potential therapeutic option in CRS, although its long-term outcomes have not been described. Methods: Retrospective registry study of the Catalan Renal Registry on patients with PD-UF indication between 2013-2022. Baseline clinical characteristics and follow-up until December/2022 was studied. Results: Of the 1874 incident patients on PD,198(10.6%) were PD-UF,73.2% of the patients were male and the mean age was70.7±9.3 years. Median eGFR at start was 22.6 [IQR14.8-32.8] ml/min·1.73m2 and 75.0% have an eGFR above 15 ml/min·1.73m2. Previous history of ischemic heart disease, arrhythmia or cardiac surgery was recorded, 57.6% of patients had ≥2 of these pathologies. The most common HF etiology was ischemic heart disease in 21.7% of patients. Median overall patient survival was 21 months [IQR17.3-24.3]. Technique survival at one year was 94.8%, and 27 patients were transferred to other renal replacement therapy (hemodialysis or kidney transplantation). In the cox multivariate analysis, age>75 years (HR 1.76[95%CI 1.20-2.59]), mild frailty (HR2.18[95%CI 1.17-2.59]), severe frailty (HR 17.62[95%CI 1.20-55.48]) and the burden of cardiac disease (2 categories HR 2.17[95%CI 1.05-4.47]; 3 categories HR 2.26 [95%CI 1.05-4.89]) were associated with poor overall survival. Technique survival was associated with eGFR (<30 ml/min·1.73m2 HR 5.64[95%CI 1.32-24.18]) and body mass index (<20 kg/m2 HR 6.53 [95%CI 1.06-40.12]) at baseline. Conclusion: PD-HF is a feasible option in patients with advanced HF and CRS. The complexity of this population increases with older age, frailty and higher cardiac burden.