Cardiovascular autonomic neuropathy associates with nephropathy lesions in American Indians with type 2 diabetes

Aims Cardiovascular autonomic neuropathy (CAN) predicts clinical diabetic nephropathy (DN). We investigated the relationship between DN structural lesions and CAN. Methods Sixty three Pima Indians with type 2 diabetes underwent kidney biopsies following a 6-year clinical trial testing the renoprotective efficacy of losartan vs. placebo. CAN was assessed a median 9.2 years later. CAN variables included expiration/inspiration ratio (E/I), standard deviation of the normal R-R interval (sdNN), and low and high frequency signal power and their ratio (LF, HF, LF/HF); lower values reflect more severe neuropathy. Associations of CAN with renal structural variables were assessed by linear regression adjusted for age, sex, diabetes duration, blood pressure, HbA1c, glomerular filtration rate, and treatment assignment during the trial. Results Global glomerular sclerosis was negatively associated with sdNN (partial r = - 0.35, p = 0.01) and LF (r = - 0.32, p = 0.02); glomerular basement membrane width was negatively associated with all measures of CAN except for LF/HF (r = - 0.28 to - 0.42, p < 0.05); filtration surface density was positively associated with sdNN, LF, and HF (r = 0.31 to 0.38, p < 0.05); and cortical interstitial fractional volume was negatively associated with HF (r = - 0.27, p = 0.04). Conclusions CAN associates with DN lesions.