Predictive value of heart rate variability on long-term mortality in end-stage kidney disease on hemodialysis.

Autonomic disturbance is common in end-stage kidney disease (ESKD). Heart rate variability (HRV) is a useful tool to assess autonomic function. We aimed to evaluate the predictive value of HRV on all-cause mortality and explore the proper timing of HRV assessment. This prospective cohort study enrolled 163 ESKD on hemodialysis patients from April-December 2018. HRV measurements were recorded ten minutes before hemodialysis, four hours during hemodialysis, and ten minutes after hemodialysis. Clinical parameters and all-cause mortality were recorded. Cox-proportional hazard regression was used for statistical analysis. After a median follow up of 40 months, 37 (22.7%) patients died. Post-dialysis HRV parameters including higher very low frequency (VLF) (hazard ratio [HR], 0.881; 95%confidence interval [CI], 0.828-0.937; p<0.001), higher normalized low frequency (nLF) (HR, 0.950; 95%CI, 0.917-0.984; p = 0.005) and higher LF/HF ratio (HR, 0.232; 95%CI, 0.087-0.619; p = 0.004) were the independent predictors associated with lower risk for all-cause mortality. Higher post-dialysis normalized high frequency (nHF) increased risk of mortality (HR, 1.051; 95%CI, 1.015-1.089; p = 0.005). HRV parameters at pre-dialysis and during dialysis were not predictive for all-cause mortality. The area under receiver operating characteristic curve (AuROC) of VLF for survival was highest compared to other HRV parameters at post-dialysis period (AuROC 0.71; 95% CI; 0.62-0.79; p<0.001). In conclusion, post-dialysis HRV parameters predicted all-cause mortaliy in ESKD. VLF measured at post-dialysis exhibited best predictive value for survival in chronic hemodialysis patients.

Effects of interdialytic interval on heart rate variability in chronic hemodialysis patients: a cross-sectional study.

Previous studies showed that long interdialytic interval of chronic hemodialysis increased risk of sudden cardiac death compared to short interdialytic interval. Diabetes mellitus (DM) and autonomic dysfunction are the strong adverse predictors of survival in ESRD patients. We aimed to compare autonomic function between long and short interdialytic interval of chronic hemodialysis in patients with and without DM. One-hundred sixty-three patients receiving chronic hemodialysis were enrolled. The electrocardiogram recording was performed twice in each patient during 4-h hemodialysis session after long and short interdialytic intervals to assess heart rate variability (HRV). Mean age was 61.4 ± 14.3 years. HRV parameters during hemodialysis did not differ between long and short interdialytic interval in overall population. Nevertheless, in 82 (50.3%) patients, SDNN (47.4 ± 23.8 vs. 43.4 ± 19.5 ms, P = 0.039), ASDNN (24.8 ± 14.3 vs. 22.7 ± 12.3 ms, P = 0.025), LF (8.4 ± 6.8 vs. 7.6 ± 6.6 ms2, P = 0.040) increased after long interdialytic interval. The greater change of SDNN, ASDNN, VLF and LF between long and short interdialytic intervals was noted in DM, compared to non-DM patients. We demonstrated that there was no difference of HRV parameters after short and long interdialytic interval. However, there was greater autonomic alteration observed in DM than non-DM patients between 2 interdialytic intervals.