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In Argentina, the 3 types of dialysis modality are performed: Low and high flow hemodialysis (HD); Peritoneal Dialysis (PD) and Online Hemodiafiltration (HDFOL). Our objective is to describe the frequency and survival associated with the dialysis modality of incident patients with chronic dialysis (CD) in Argentina.
Observational retrospective cohort study. All incident adult patients (≥ 18 years) to dialysis in the period of 17 years (2004-2021), identified in the Argentine Dialysis and Transplant Registry, were included. In Argentina, it is mandatory the registration of incident patients on chronic renal replacement therapy and organ transplantation. This registration contains identification data, laboratory analyses, type of dialysis, vascular access and patient's comorbidities as well as the cause of ending renal replacement therapy (death). These variables are registered in an online form called DRI, which ensures data availability from all the country.
The survival of the patients in DC was established, and the significant variables associated with survival were considered.
As the HDFOL was incorporated in Argentina in 2014, to compare the survival rate of patients who initiated DC with HD, DP and HDFOL, the population between 1/1/2015 and 12/31/2021 was evaluated. Student's t-test, Wilcoxon test and Pearson Chi2 test were applied as appropriate. For survival analysis, the Kaplan Meier curves were constructed (log-rank test) and Cox proportional-hazards model adjusted for the significant variables. At p <0.05 was considered significant. The MedCalc statistical program was used.
115,972 patients were included (59 ± 17 years old; 41.2% female), of which 57,675 died (48.7%), with a median survival of 44.8 months. Associated with higher mortality were age at admission, cardiovascular disease, Chronic Pulmonary Disease, Neoplasia, Hypoalbuminemia, Anemia, Diabetic Nephropathy, Transient vascular access among the main variables.
The most used modality in order of highest frequency in 2021 was HD 86.4%; DP 8.3% and HDFOL 5.3%.
49,609 patients with a maximum follow-up time of 84 months and an overall mortality of 36.9% were considered for the comparison of survival of dialytic modalities. Motality for each of the modalities was 38%, 19.2% and 18% for HD, PD and HDFOL respectively in the analyzed period. Survival associated with PD and OL HDF was significantly greater than HD up to 88 months. At 60 months, a survival of 56.5% for PD, 54.0% for OL HDF and only 37.4% for HD is observed (p=0.000), see graph 1.
In the adjusted Cox regression model, PD and OLHDF remain significantly superior to HD, starting on PD or OL HDF decreases the relative risk of death between 35% and 48% when compared to starting on HD, in the incident population in DC of Argentina from the period 2015-2021, see graph 2.
It is worth highlighting the limitations of the number of patients included in HDFOL, such as the strength of a real-life study.
Conclusions
HD continues to be the most common renal replacement therapy in Argentina, despite the survival advantages observed with PD. As demonstrated by the latest clinical trials, OLHD is associated with greater survival in this patient population.