Heart Rate Variability Change Before and After Hemodialysis is Associated with Overall and Cardiovascular Mortality in Hemodialysis

Low heart rate variability (HRV) has been recognized to correlate with adverse cardiovascular (CV) outcomes in hemodialysis (HD) patients. It has been reported that HRV might be improved after HD, but whether the improved HRV after HD predicts a better CV prognosis remains to be determined. This study examined the ability of the change in HRV before and after HD in predicting overall and CV mortality in HD patients. This study enrolled 182 patients under maintenance HD. HRV was examined to assess changes before and after HD. The change in HRV (Delta HRV) was defined as post-HD HRV minus pre-HD HRV. During a median follow-up period of 35.2 months, 29 deaths (15.9%) were recorded. Multivariate analysis showed that decreased Delta LF% was associated with increased overall (hazard ratios [HR], 0.978; 95% confidence interval [CI], 0.961-0.996; p = 0.019) and CV mortality (HR, 0.941; 95% CI, 0.914-0.970; p < 0.001), respectively. Moreover, adding Delta LF% to a clinical model provided an additional benefit in the prediction of overall (p = 0.002) and CV mortality (p < 0.001). HRV change before and after HD (Delta HRV) is an useful clinical marker, and it is stronger than HRV before HD in predicting overall and CV mortality.