Heart Rate Variability as a Marker of Cardiac Autonomic Neuropathy and Autonomic Dysfunction in Prediabetic Patients: A Retrospective Study
Cantürk Kaya1, Turgay Aslan2, Ceyla Konca Değertekin1, Uğur Erçin3, Özge Kurmuş21Department of Internal Medicine, Ufuk University, Ankara, Türkiye2Department of Cardiology, Ufuk University, Ankara, Türkiye
3Department of Medical Biochemistry, Ufuk University, Ankara, Türkiye
INTRODUCTION: Heart rate variability has been associated with autonomic neuropathy, which is seen in diabetes. Cardiac autonomic neuropathy is found to be related to a poor prognosis in diabetic patients. It is thought that neuropathy that develops in diabetic patients begins in the early stages. We aimed to assess heart rate variability (HRV) in prediabetic patients to explore whether autonomic changes may begin during the prediabetes stage.
METHODS: This retrospective study included prediabetic patients who underwent 24-hour Holter ECG monitoring. Patients were identified based on fasting plasma glucose (FPG) and HbA1c values extracted from medical records. Prediabetes was defined as HbA1c 5.7–6.4% and fasting plasma glucose 100–126 mg/dL. Patients with thyroid dysfunction, overt diabetes, arrhythmias or those using drugs affecting heart rate were excluded. HRV parameters, including SDNN, SDANN, rMSSD, pNN50, triangular index, and frequency-domain measures (LF, HF, VLF, LF/HF), were analysed.
RESULTS: Fifty participants were included (25 prediabetic, 25 controls). The groups were similar in age and sex. All HRV parameters were lower in prediabetic patients compared to controls. Time-domain measures SDANN, rMSSD, pNN50, and triangular index and frequency-domain measures HF, VLF, and LF/HF ratio were significantly reduced (p < 0.05). Effect sizes and 95% confidence intervals were reported, and sensitivity analyses adjusted for age and sex confirmed findings.
DISCUSSION AND CONCLUSION: HRV is reduced in prediabetic patients, consistent with early autonomic dysfunction. These findings suggest that cardiac autonomic neuropathy may begin in prediabetic patients. All HRV parameters were lower than those of the control group and can serve as non-invasive indicators of early autonomic dysfunction and cardiac autonomic neuropathy.
Keywords: Prediabetes, heart rate, autonomic neuropathy.
Manuscript Language: English