# Comparison of Heart Rate Variability in People With Diabetes-Related Neuropathic Foot to Their Counterparts Without a Foot Ulcer History: A Propensity Score Matching Study

## TL;DR

People with diabetic foot ulcers have worse heart rate variability, indicating more severe heart function issues, compared to those without ulcers.

## Contribution

This study identifies significant differences in cardiac autonomic function between individuals with and without diabetic foot ulcers using propensity score matching.

## Key findings

- Individuals with DFU had lower HRV measures compared to those without DFU.
- DFU was independently and negatively associated with all HRV measures.
- DFU patients had a 2.5-fold increase in severe cardiac autonomic impairment.

## Abstract

Background: The reasons that individuals with diabetic foot ulceration (DFU) have higher cardiovascular mortality than those with Type 2 diabetes mellitus (T2DM) but without DFU remain controversial. We aimed to compare the differences in cardiac autonomic function between individuals with neuropathic DFU and their counterparts without DFU.

Methods: Three hundred and sixty-two participants with T2DM (181 with DFU and 181 without DFU) who were free of peripheral artery disease (PAD) were included in the final analysis after propensity score matching (PSM). All individuals underwent a 24-h ECG Holter and used the following indices of heart rate variability (HRV) to assess cardiac autonomic function: the standard deviation of the normal sinus interval (SDNN), the root mean square of successive RR interval differences (rMSSD), the standard deviation of the 5-min average RR intervals (SDANN), the percentage of normal adjacent RR interval difference > 50 ms (PNN50), the low-frequency power (LF), the high-frequency power (HF), and the LF/HF ratio.

Results: Individuals with DFU had lower SDNN, LF/HF, PNN50, rMSSD, HF, SDANN, and LF than their counterparts without DFU (all p < 0.05). Individuals with DFU had a 2.5-fold increase in severe impairment of cardiac autonomic modulation (i.e., SDNN < 50 ms) compared to those without DFU (21.6% vs. 8.8%, p < 0.001). DFU was independently and negatively associated with all the abovementioned HRV measures (all p < 0.05).

Conclusion: Among people with neuropathic diabetic foot only, cardiac autonomic function was still more severely impaired in individuals with DFU than in their counterparts without DFU.

Trial Registration:
CHiCTR2300076628