Cardiovascular autonomic neuropathy in chronic kidney disease: A study of kidney biopsy cases

Background The interplay between cardiac and kidney functions is mediated by the autonomic nervous system. Cardiovascular autonomic neuropathy (CAN) is a well-documented dysfunction of this system, with heart rate variability (HRV) serving as the principal diagnostic tool. CAN is recognised as a prognostic marker for adverse kidney outcomes in diabetic kidney disease (DKD). However, the pathogenesis of CAN in patients with non-diabetic chronic kidney disease (CKD) remains underexplored. This study explored the clinicopathological correlates of CAN in individuals with non-diabetic CKD. Methods This cross-sectional analysis evaluated 162 non-diabetic patients with CKD who underwent kidney biopsy from 2020 to 2023. HRV was quantified using the coefficient of variation of the RR interval (CVRR). Clinicopathological characteristics were compared across tertile groups stratified according to CVRR values. Results The median patient age was 47.0 (34.0–57.0) years, and 50.9% were male. The median estimated glomerular filtration rate was 65.0 (42.0–85.0) mL/min/1.73 m ² , and the CVRR was 3.5 (2.4–4.7) %. Low CVRR group was frequently associated with kidney dysfunction, dyslipidemia, advanced interstitial fibrosis/tubular atrophy (IF/TA) and arteriosclerosis. Multivariable analysis revealed that IF/TA was associated with CVRR, independent of established risk factors for CAN ( P  = 0.045). Conclusions This investigation revealed that IF/TA was the renal histopathological feature most strongly correlated with CAN in patients with non-diabetic CKD