Heart Rate Variability and Ewing's Battery-Derived Cardiac Autonomic Neuropathy in Prediabetic versus Healthy Adults: A Case-Control Study from Central India

Abstract

Aims: Prediabetes affects an estimated 136 million Indian adults, with central India identified as a region of disproportionate burden. We assessed and compared heart rate variability (HRV) and Ewing's-battery-derived cardiac autonomic neuropathy (CAN) between prediabetic and healthy adults, and correlated autonomic indices with clinical and biochemical parameters.

Methods: In this age- and sex-matched case-control study, 100 prediabetic adults (ADA 2024 criteria) and 100 healthy controls underwent anthropometric and biochemical assessment, 5-minute resting HRV recording, and the five-test Ewing battery. Between-group comparisons used the independent t-test/Mann-Whitney U test, Chi-square/Fisher's exact test, Pearson/Spearman correlation, and multiple linear regression (α=0.05).

Results: All time- and frequency-domain HRV parameters and all five Ewing-battery components were significantly impaired in prediabetic participants (p<0.001). CAN, graded by composite Ewing score, was present in 100% of prediabetic participants (63% Early, 21% Definite, 16% Severe) versus 3% of controls (p<0.001). Within the prediabetic group, waist circumference, not BMI or glycaemic indices, was the only significant independent predictor of SDNN (β=−0.68 ms/cm, p=0.019; model R²=0.114).

Conclusions: Cardiac autonomic dysfunction is already measurable, and in this cohort near-universal, in prediabetic adults, and correlates more consistently with central adiposity than with glycaemia. These findings support incorporating brief, non-invasive autonomic screening into the routine evaluation of prediabetic individuals in high-burden Indian populations.