The Impact of COVID-19 on Long-Term Mortality in Maintenance Hemodialysis: 5 Years Retrospective Cohort Study

Background: Hemodialysis (HD) patients are a highly vulnerable population with elevated mortality driven by comorbidities and dialysis-specific factors. While most studies focused on intra-pandemic outcomes, long-term effects remain underexplored. We aimed to evaluate 5-year mortality and the impact of COVID-19 vaccination in chronic HD patients. Methods: A retrospective study was conducted on 211 HD patients monitored between 2020 and 2024. Outcomes included overall and cardiovascular mortality, risk factors in COVID-19-positive patients, and vaccination impact. Logistic regression identified independent predictors. Results: The cohort had a mean age of 65.6 ± 13.3 years, with 55.9% males and mean dialysis vintage of 6.9 ± 5.5 years. Overall mortality reached 53.6%, while 38.4% were vaccinated. Predictors of all-cause mortality included age (OR = 1.078, p < 0.001), BMI (OR = 0.868, p < 0.001), hemoglobin (OR = 0.581, p < 0.001), phosphorus (OR = 1.351, p = 0.025), dialysis adequacy (OR = 0.138, p = 0.013), and ischemic cardiopathy (OR = 0.327, p = 0.009). In COVID-19-positive patients, mortality was associated with age (OR = 1.069, p = 0.002), low hemoglobin (OR = 0.642, p = 0.014), BMI (OR = 0.885, p = 0.009), CRP (OR = 1.015, p < 0.001), and coronary artery disease (OR = 5.68, p < 0.001). Cardiovascular disease was the leading cause of death (44.6% in COVID-19-positive vs. 73.3% in negatives, p = 0.006). Vaccination significantly reduced COVID-19-related mortality (OR = 0.023, p = 0.005) but did not influence overall or non-COVID mortality. Conclusions: Five-year mortality in HD patients remained high, mainly cardiovascular, and was strongly influenced by age, BMI, hemoglobin, dialysis adequacy, and comorbidities. COVID-19 vaccination substantially reduced COVID-related mortality but did not alter all-cause outcomes. These findings support vaccination and careful risk stratification in HD populations for future pandemics.