#2958 SURVIVAL OF HEMODIALYSIS PATIENTS: A LARGE RERTOSPECTIVE STUDY
Authors: Morisi Niccolò , Scarmignan Roberta , Alfano Gaetano , Donati Gabriele 
Published: June 2023

Abstract

Background and Aims
Despite the evolution of haemodialysis (HD) technique, long-term prognosis for HD patients remains poor. The major causes of mortality for HD patients are cardiovascular diseases, followed by infections and tumors. Survival difference between HD and general population is related to chronic exposition to uremic toxin and continuous cardiovascular stress. Corrently there is no consensus about the weight of different mortality factors. Our aim is to delve into some risk factors using a large sample of HD patients.

Method
We performed a longitudinal retrospective analysis with data collected from patients that started HD from 1969 to 2021 in the dialysis center of Modena, Italy. Patients with &lt; 18 years old or &lt; 3 months of HD were excluded. The included characteristics were sex, age of starting HD and duration of treatment, any previous substitutive treatment (e.g., peritoneal dialysis (PD), transplant (TX)) and inscription on waiting list for TX. Statistical tests were performed using Shapiro-Wilk, t-test and ANOVA. Survival analysis was employed using the Kaplan–Meier estimate and Cox regression models with 95% confidence interval (CI).

Results
A total of 2290 patients were submitted to study, 63% of them were male (n = 1451), 10% were placed on waiting list for Tx (n = 224) and 9% came from any substitutive treatment (n = 45 from Tx, n = 154 from PD). At time of HD started, average age was 67,7 (Standard Deviation: 14,8 years). In this group, 22% (n = 504) were older than or equal to 80 years, 40% (n = 911) were between 80 and 65 years, 23% (n = 534) were between 65 and 50 years, 15% (n = 341) were younger than 50 years. The average survival in HD was 1894,2 days, 80% of patients died (n = 1829) and 9% recived kidney transplant (n = 190). One-year mortality rate was 13% (n = 297), with the highest mortality rate in the eldest people (n = 115, Log-Rank p&lt;0,0001). At fifteen years of follow-up 76% died (n = 1740) and 8% (n = 183) were submitted to transplant. Age remained an important risk factor of mortality (Log-Rank p&lt;0,0001) (Figure 1). Conversely, inscription on waiting list for TX (Log-Rank p&lt;0,0001) and previous DP (Log-Rank p = 0,0002) were protective factors. An important mortality predictor at 15 years was the age of beginning HD (p&lt;0,0001). Indeed, using patients with &lt;50 years as dummy variable, patients with age between 50 and 65 years had hazard ratio (HR) of 2,7 (CI 2,2-3,4); HR for age between 65 and 80 years was 5 (CI 4,1-6,1); patients aged &gt;80 years had HR of 11 (CI 8,9-13,7). Other mortality predictors were the inscription on waiting list (HR 0,4, CI 0,2-0,5, p&lt;0,0001) and previous PD treatment (HR 0,76, CI 0,61-0,95, p = 0.01). Sex and previous transplantation were not statistically significant.

Conclusion
The medical progress reached nowadays allows us to keep patients longer out of HD. This leads to an increasing average age of patients starting hemodialysis. Our results show that age is an important factor to determine the survival in HD and this becomes dramatically true for octogenarian patients. On the other side, patients on the waiting list for transplant have a better survival, probably due to a better health status. In conclusion, the challenge of the future will be to act on modifiable risk factors with adequate prevention and treatment of comorbidities. This will allow us to reduce the weight of age as a mortality predictor.