title: Cardiac autonomic neuropathy predicts renal function decline in patients with type 2 diabetes: a cohort study.
abstract: OBJECTIVE
  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
  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.
authors.affiliation: Centre of Endocrinology, Diabetes and Metabolism, Institute of Biomedical Research, The Medical School, University of Birmingham, Birmingham, B15 2TT, UK, a.a.tahrani@bham.ac.uk.
authors.forename: Abd A
authors.initials: AA
authors.lastname: Tahrani
authors.forename: Kiran
authors.initials: K
authors.lastname: Dubb
authors.forename: Neil T
authors.initials: NT
authors.lastname: Raymond
authors.forename: Safia
authors.initials: S
authors.lastname: Begum
authors.forename: Quratul A
authors.initials: QA
authors.lastname: Altaf
authors.forename: Hamed
authors.initials: H
authors.lastname: Sadiqi
authors.forename: Milan K
authors.initials: MK
authors.lastname: Piya
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Stevens
mesh_terms: D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003929:Diabetic Neuropathies / Q000150:complications*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000209:etiology*