Low-Frequency/High-Frequency Ratio Is a Predictor of Death and Hospitalization in Patients on Maintenance Hemodialysis: A Prospective Study.

Introduction: This study aimed to evaluate the predictive value of the low-frequency/high-frequency (LF/HF) ratio in all causes of death and hospitalizations in maintenance hemodialysis (MHD) patients.

Methods: This is a single-center prospective study with a 48-h electrocardiograph (ECG) recording. A total of 110 patients were enrolled in the study from October 1, 2021, to September 30, 2022. ECG recordings started before initiation of the hemodialysis (HD) session and lasted for 48 h, covering the intra- as well as inter-HD period. We divided our participants into two groups based on the median value of LF/HF, one of the frequency domain parameters of heart rate variability (HRV). Patients with LF/HF <1.33 were categorized as group A and those with LF/HF ≥1.33 were group B. The endpoint of the study was a composite event of death or hospitalization. We followed all patients until the composite endpoint or the end of the study on February 28, 2023. Multivariate Cox regression was used to assess the adjusted effect of LF/HF on the composite endpoint.

Results: Patients in group A were older and the number of patients with diabetes was more than that of group B. With regards to the laboratory data, group A had lower serum creatinine and uric acid and higher ferritin and NT-ProBNP. In the index HD session, systolic blood pressure was higher but diastolic blood pressure was significantly lower in group A. During the median follow-up period of 8.8 (7.6-9.8) months, 27 hospitalizations and 10 deaths were documented. Increased LF/HF ratio was an independent protective factor of composite endpoint events (HR = 0.357, 95% CI: 0.162-0.790, p = 0.011).

Conclusion: Risks of mortality and hospitalizations are higher among HD patients having decreased LF/HF ratios. LF/HF in the 48-h recording can be considered as a prognostic factor for risk stratification in HD patients.