Autonomic Dysfunction Predicts Long-Term Mortality in Hypotensive Hemodialysis Patients: Prognostic Value of Heart Rate Variability and Turbulence

Purpose Autonomic dysfunction has been implicated in adverse outcomes in end-stage renal disease. However, the prognostic significance of heart rate variability (HRV) and turbulence (HRT) in chronically hypotensive hemodialysis (HD) patients remains unclear. Therefore, the present study aimed to investigate the association between baseline autonomic markers and all-cause mortality using time-to-event analyses. Methods A total of 44 hypotensive and 46 normotensive HD patients who underwent 24-h ambulatory blood pressure monitoring and Holter recording during the interdialytic period were included in this prospective observational cohort study. Moreover, their HRV and HRT parameters were analyzed. Patients were monitored for all-cause mortality outcomes, and survival analyses were performed. Results During follow-up, 39 patients (43.3%) died. Non-survivors had significantly lower standard deviation of the averages of normal-to-normal intervals in all 5-min segments (SDANN) (101.49 ± 11.03 ms vs. 105.80 ± 8.79 ms; p = 0.042) and markedly impaired turbulence onset (TO) (− 1.92 ± 0.42 vs. −2.40 ± 0.43; p < 0.001) compared with survivors. Kaplan–Meier analysis demonstrated significantly reduced survival among patients with abnormal autonomic parameters (standard deviation of all normal-to-normal intervals, SDANN, TO; p < 0.001). In multivariable Cox regression analysis, TO emerged as the strongest independent predictor of mortality (p < 0.001). Conclusion Impaired TO is a powerful and independent predictor of long-term mortality among hypotensive HD patients. These findings indicate that TO is a promising noninvasive marker for risk stratification and that autonomic failure plays a central mechanistic role in adverse outcomes in this high-risk population.