Cardiac autonomic neuropathy predicts renal function decline in patients with type 2 diabetes : a cohort study

Aims/hypothesis: The aim of this work was to assess the impact of cardiac autonomic neuropathy (CAN) on the development and progression of chronic kidney disease (CKD) in patients with type 2 diabetes. Methods: We conducted a cohort study in adults with type 2 diabetes. Patients with end-stage renal disease were excluded. CKD was defined as the presence of albuminuria (albumin/creatinine ratio GFR >∈3.4 mg/mmol) or an estimated (eGFR) <∈60 ml min ^-1 1.73 m ^-2. CKD progression was based on repeated eGFR measurements and/or the development of albuminuria. CAN was assessed using heart rate variability. Results: Two hundred and four patients were included in the analysis. At baseline, the prevalence of CKD and CAN was 40% and 42%, respectively. Patients with CAN had lower eGFR and higher prevalence of albuminuria and CKD. Spectral analysis variables were independently associated with eGFR, albuminuria and CKD at baseline. After a follow-up of 2.5 years, eGFR declined to a greater extent in patients with CAN than in those without CAN (-9.0∈±∈17.8% vs -3.3∈±∈10.3%, p∈=∈0.009). After adjustment for baseline eGFR and baseline differences, CAN remained an independent predictor of eGFR decline over the follow-up period (β∈=∈-3.5, p∈=∈0.03). Spectral analysis variables were also independent predictors of eGFR decline. Conclusions/interpretation: CAN was independently associated with CKD, albuminuria and eGFR in patients with type 2 diabetes. In addition, CAN was an independent predictor of the decline in eGFR over the follow-up period. CAN could be used to identify patients with type 2 diabetes who are at increased risk of rapid decline in eGFR, so that preventative therapies might be intensified.