Subclinical kidney disease is associated with diabetic autonomic neuropathy

Background: A relationship between chronic kidney disease (CKD) and heart rate variability (HRV) has been reported. Patients with CKD have an abnormally low HRV, which contributes to increased risk of heart attack. However, studies of patients with a decreased eGFR above the clinical cut-off point (>60 ml/min) but below normal (90 ml/min) have not been reported. Therefore our study concentrated on determining whether HRV is affected in people with lowered eGFR and whether diabetes has an effect on HRV in mild/subclinical renal disease, that is 60 ml/min < eGFR < 90 ml/min but above 60 ml/min.Methods and Results: Fifty-five patients were included in this study. Patients were divided into two groups: Control (n = 45) and Diabetic (n = 10). A 20 min lead II ECG was recorded for each patient and analysed (Chart 5; ADInstruments). The control and diabetes group was further divided in to those with 60 ml/min < eGFR < 90 ml/min and those with an eGFR < 60 ml/min. No exclusion criteria were applied. Analysis of data was with ANCOVA (SPSS V17). Significance was set at p < 0.05. There was a significant (p = 0.0125) interaction between eGFR and diabetes status. Our results indicated that lowered eGFR did not affect HRV in nondiabetics but had an effect in people with diabetes.Discussion: Heart function was significantly related to diabetes and eGFR status even with clinically normal kidney function. This suggests that regular screening of kidney function and the presence of diabetic dysautonomia should be carried out from the time of diabetes diagnosis.