Diagnostic Utility of Heart Rate Variability, Baroreflex Sensitivity, and Blood Pressure Variability for Detecting Early Cardiovascular Autonomic Dysfunction in Cardiovascular Autonomic Neuropathy in Prediabetic Women – A Cross-sectional Study

Abstract

The present study was undertaken to systematically evaluate the diagnostic utility and association of heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) in prediabetic women for early detection of cardiac autonomic neuropathy (CAN). By examining these three interlinked regulatory domains within the same individuals, this study aimed to capture a comprehensive snapshot of early neurocardiovascular dysregulation in prediabetes. This cross-sectional, comparative study was conducted amongst a total of 100 women, comprising 50 prediabetic women and 50 normoglycemic controls with no history of diabetes, hypertension, cardiovascular disease, or autonomic neuropathy. Individuals with smoking, alcohol use, thyroid disease, arrhythmias, anemia, or medications affecting autonomic function were excluded. All participants underwent detailed clinical evaluation, anthropometry, and fasting biochemical testing including fasting blood sugar (FBS), glycosylated hemoglobin A1c (HbA1c), lipid profile, and renal parameters. Resting blood pressure was measured, and systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) variability were recorded. Cardiac autonomic function testing included: (1) HRV measured using a 10-min electrocardiogram recording analyzed for time-domain (standard deviation of normal-to-normal, root mean square of successive differences, pNN50), frequency-domain (low frequency [LF], high frequency [HF], LF/HF ratio), and non-linear indices (standard deviation [SD]1, SD2). (2) Spontaneous BRS assessed using the sequence method for SBP-BRS, DBP-BRS, and MBP-BRS, and (3) BPV was calculated from beat-to-beat recordings of SBP, DBP, and mean arterial pressure. Statistical analysis used appropriate tests for group comparison, Pearson correlation for associations, multinomial logistic regression for independent predictors, and receiver operating characteristic (ROC) curves to assess diagnostic performance, with area under the curve (AUC) values interpreted per standard guidelines. ROC curves were constructed using prediabetes status as the binary outcome variable to assess the discriminatory ability of autonomic parameters. Among 100 women (50 prediabetic; 50 controls), prediabetes was associated with significantly higher cardiometabolic risk (higher body mass index, SBP/DBP, low-density lipoprotein, triglycerides and HbA1c. Prediabetic women demonstrated markedly reduced HRV across time, frequency and non-linear indices ( p < 0.001), with excellent discriminatory ability (AUC 0.86–0.90). BRS was significantly lower in prediabetics ( p < 0.001), demonstrated good discriminatory ability (AUC 0.87). 44% met criteria for definite CAN, and 86% had ≥1 abnormal autonomic test. BPV indices did not differ significantly at the group level; however, fasting glucose showed strong negative correlations with short-term SBP, DBP and MBP variability in prediabetics. Multivariable models showed that HRV impairment was independently associated with both SBP load and HbA1c. Prediabetic women exhibit early, substantial, and measurable cardiac autonomic dysfunction, with HRV and BRS demonstrating good discriminatory ability. BPV changes appear subtle but correlate strongly with glycemia, suggesting a possible role as an early vascular-autonomic marker. Early autonomic assessment in prediabetes may enable timely detection of high-risk individuals.