#529 Educational level and mortality in patients receiving chronic hemodialysis in Lazio Region—Italy
Authors: Marino Claudia , Angelici Laura , Giaccari Marta , Cesaroni Giulia , Cascini Silvia , Bargagli Anna Maria , Davoli Marina , Agabiti Nera 
Published: May 2024

Abstract

Background and Aims
In 2010, 2.6 million people received Kidney Replacement Treatment (KRT) worldwide. Hemodialysis (HD) is the most commonly used KRT. HD patients have a consistent risk of death. The impact of Educational Level (Edl) on the mortality in HD patients is unclear. This study aims to analyse the association between the Edls and mortality in incident chronic HD patients using the Lazio Regional Dialysis and Transplant Registry.

Method
A cohort of incident HD patients between 2008 and 2022 was selected. Patients under 18 years old and with a follow-up period shorter than 91 days were excluded. All patients were characterized by sociodemographic and clinical characteristics at the incident date and were followed from the incident date until the earliest of the following dates: death, transplantation, renal function recovery or end of the study (one or three years after initiation). One-year and three-year Crude Mortality Rates*100 Person Years (CMR*100PY) overall and by Edal (low: up to primary school, medium: secondary school, high: university degree and more) were calculated. Cumulative survival estimates at one year and three years since starting HD, were presented as Kaplan-Meier curves by EdL and compared using the log-rank test. Crude and adjusted Hazard Ratios (HR) and respective 95% Confidence Intervals (95% CI) of the association between EdL and one and three-year mortality were calculated using univariate and multivariate Cox regression models (reference category: low EdL). Sociodemographic and clinical characteristics were considered potential confounders or effect modifiers in the adjusted Cox regression models.

Results
The cohort counted 9,776; 33.5% had a low EdL, 30.7% had a medium, and 35.8% had a high EdL. The mean age decreased with increasing EdL (73 and 65 in low and high EdL, respectively) as the proportion of females (43.0% and 26.0% in low and high EdL, respectively). During the first year of HD, 1,683 deaths occurred, and 3,827 occurred within three years. One-year CMR*100PY were 24.1 (95% CI 22.4-26.0) in low EdL, 17.4 (95% CI: 15.9-19.0) in medium EdL and 15.0 (95% CI: 13.8-16.4) in high ED. The corresponding three-year CMR were 22.7 (95% CI 21.6-23.8), 17.4 (95% CI 16.4-18.4) and 15.1 (95% CI 14.2-16.0). One-year survivals estimates were 78.0% in low EdL, 83.8% in medium and 85.8% in high EdL (log-rank test: p-value &lt; 0.001). The three-years survival estimates were 51.0% in low EdL, 59.3% in medium EdL and 63.7% in high EdL (log-rank test: p-value &lt; 0.001). In one-year mortality the crude HRs were 0.72 (95% CI: 0.64–0.81) and 0.62 (95% CI: 0.55–0.70) of medium and high EdL vs. low EdL respectively; the corresponding adjusted HRs were 0.93 (95% CI: 0.83–1.06) and 0.92 (95% CI: 0.81–1.04) (Fig. 1). Similar results were obtained for three-year mortality: crude HRs were 0.77 (95% CI: 0.71–0.83) and 0.66 (95% CI: 0.62–0.72); adjusted HRs were 0.99 (95% CI: 0.92–1.08) and 0.97 (95% CI: 0.89–1.06), respectively (Fig. 2).).

Conclusion
Based on the present study, high educational level does not appear to be associated with lower mortality risk at either one-year or three-years. Hemodialysis patients are constantly monitored by National Health Service; this probably cancels the effect of low educational level on mortality. Although EdL is a strong indicator of socioeconomic position, it does not capture all dimensions of disadvantage. The mechanisms that underline the poor prognosis in Haemodialysis patients are complex and further investigations are needed.