#841 Hemodialysis in focus: patient survival through the lens of time and hazard factors

Abstract Background and Aims Hemodialysis (HD) patients are at high mortality risk, especially during the first year of treatment, due to insufficient adaptation (USRDS, 2020). Those undergoing HD for more than five years exhibit better survival rates, but remain vulnerable to chronic complications (ERA-EDTA, 2018). This study aims to evaluate the impact of key hazard factors (hazard ratio - HR) on survival in HD patients. Method A prospective cohort study involved 120 HD patients aged 18-68 years over a 12-month period. Patients were divided into three groups according to the HD duration: Group 1—up to 12 months (n = 38), Group 2—13–60 months (n = 55), Group 3—over 60 months (n = 27). The study assessed forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) of lungs using spirometry. During the HD session, arterial blood pressure (BP), heart rate (HR), and blood oxygen saturation (SpO₂) were monitored using portable automated device and non-invasive pulse oximetry. Statistical analysis was performed using Cox regression, correlation analysis (r), χ²-test, and mean comparison. Results Key mortality and complication HRs included: male gender (HR = 1.14; 95% CI: 1.03−1.26; P = 0.009), age over 60 (HR = 1.3; 95% CI: 1.12−1.49; P = 0.00044), and inter-dialytic weight gain (IDWG >3.5 kg) (HR = 1.8; 95% CI: 1.5−2.2; P = 0.0002). Among comorbidities, the highest hazards are associated with diabetes mellitus (DM) (HR = 1.7; 95% CI: 1.3−2.2; P = 0.0005), hypoglycemia episodes (HR = 1.6; 95% CI: 1.2−2.0; P = 0.0017), and prolonged intradialytic hypoxemia (PIH) (HR = 2.07; P < 0.001). For arterial hypertension (AH), the hazard was HR = 1.5 (95% CI: 1.1−2.0; P = 0.0018), while for blood pressure variability (BPV >10 mmHg), HR = 1.3 (95% CI: 1.0−1.6; P = 0.023) (Fig. 1). Patients in Group 1 had the highest HR = 1.8 (95% CI: 1.3−2.5), P = 0.01; followed by Group 2—HR = 1.3 (95% CI: 1.1−1.5), P = 0.05; while patients in Group 3 showed a trend toward better survival, HR = 1.0 (95% CI: 0.9−1.2), P = 0.1. However, differences between the groups based on HD duration were not statistically significant (P = 0.114) (Fig. 2). In Groups 1 and 3 patients, a statistically significant relationship was found between actual and predicted FEV1 values: ra = 0.93; pa = 0.002; rp = 0.766; pp = 0.0059 indicating that the pulmonary function is preserved in patients with HD >60 months. At the same time, HD duration strongly correlates with obstructive disorders (r = 0.99; P < 0.001), suggesting progressive obstructive changes over time. HD duration >60 months is associated with worsening dyspnea (r = −0.91; P = 0.032) but negatively correlates with IDWG frequency (r = −0.87; P = 0.002), reflecting better fluid balance control in Group 3 patients. Group 3 had the lowest proportion of patients with AH compared to Groups 1 and 2 (χ² = 8.44; P = 0.015), but the highest frequency of intradialytic hypotension (P = 0.013), highlighting the need for careful BP monitoring in this category of patients. The difference in mean HR values across the groups was 10 beats/min (95% CI: 3.52−16.48; P = 0.027). Group 1 patients had a higher HR compared to those with HD duration >60 months (P = 0.035). HD duration had no statistically significant impact on the presence or absence of PIH (P = 0.2776). Conclusion Survival in HD patients is determined by multiple hazard factors. Diabetes and hypoglycemia have a significant impact, as do effective IDWG control and BPV levels. Prolonged PIH is associated with increased mortality risk. Long-term HD therapy also affects the respiratory function: while the lungs adapt with partial preservation of the function, obstructive disorders progress, and dyspnea worsens over time. Longer HD duration improves fluid balance control; however, patients with extended HD duration experience a higher risk of intradialytic hypotension. Patients with HD duration <12 months have the highest mortality risk, while prolonged treatment (>60 months) shows a trend towards improved survival, although differences between groups were not statistically significant.