#705 Survival of Expanded Hemodialysis and High-Flux Hemodialysis Patients in Colombia: a Cohort's Study

Abstract Background and Aims Survival is a core outcome of hemodialysis (HD) therapy. Progressive improvement in the permeability and biocompatibility of membranes for HD, dialysis techniques and clinical processes around these therapies have been developed. Recently, expanded hemodialysis (HDx) enabled by the medium cut-off membrane Theranova® has demonstrated encouraging efficacy outcomes in terms of better clearance of medium molecules and better outcomes reported by patients when compared to high-flux hemodialysis membranes (HF HD). The objective of the present study is to compare survival in an HDx cohort versus an HF HD cohort at a 48-month follow-up. Method Cohort study, one group with expanded haemodialysis (HDx) enabled by Theranova® and the other with HF HD, adult prevalent HD patients (> 90 days) at Baxter Renal Care Services Colombia starting between September 1, 2017, and November 30, 2017, with follow-up for up to 48 months. The sociodemographic and clinical characteristics of all patients were summarized descriptively. A Fine-Gray regression model was performed to evaluate the factors associated with time to death from causes other than COVID-19, death attributable to COVID-19 cause is a competing risk. A sensitivity analysis was performed using different statistical methods, such as extended Cox regression and Cox regression, after adjusting for imbalance between the cohorts with the inverse probability of treatment weighting (IPTW) method. Results We evaluated 1092 patients, 533 in HF-HD vs 559 in HDx; the mean age 61 years; 42% had diabetes, and 19% had cardiovascular disease. All patients' sociodemographic and clinical characteristics are summarized descriptively by cohort arm (Table 1). A multivariate analysis was performed to evaluate the effect of demographic, clinical, and laboratory variables on the risk of death, adjusting for the competing risk of death from COVID-19 during four years of follow-up. Our results indicate that the Theranova dialyzer has a protective effect on mortality risk when controlling for confounding variables SHR = 0.75 [95% CI: 0.58 to 0.95, p-value = 0.019] (Table 2). The different sensitivity analyses report a statistically significant beneficial effect of Theranova versus HF dialyzer. See Table 3. Fig. 1 shows a difference in the survival functions according to the type of dialyzer. Conclusion HDx enabled by Theranova dialyzer was associated with an approximately 25% reduction in mortality risk compared to HF HD patients followed for up to 4 years; this effect was consistently observed using different survival analysis methods.