Foot insensitivity is associated with renal function decline in patients with type 2 diabetes: a cohort study.

BACKGROUND: Identifying patients with diabetes at increased risk of chronic kidney disease (CKD) is essential to prevent/slow the progression to end-stage renal disease (ESRD). CKD and diabetic peripheral neuropathy (DPN) share common mechanisms. Hence, we aimed to examine the relationship between foot insensitivity and CKD in patients with Type 2 diabetes. METHODS: A prospective observational cohort study in adults with Type 2 diabetes. Patients with ESRD were excluded. Foot insensitivity was assessed using the 10-g monofilament test. Renal function was assessed using estimated glomerular filtration rate (eGFR) based on the MDRD equation. Albuminuria was defined as the presence of urinary albumin/creatinine ratio (ACR) >3.4 mg/mmol. RESULTS: Two hundred and twenty eight patients were recruited and followed-up for 2.5 years. One hundred and ninety patients (83.4%) had eGFR ≥ 60 ml/min/1.73 m2. Seventy six (33.3%) patients had foot insensitivity (i.e. abnormal monofilament test). Patients with foot insensitivity had lower eGFR and higher prevalence of albuminuria compared to patients with normal monofilament test. After adjustment for age, gender, ethnicity, diabetes duration, HbA1c, body mass index, insulin treatment, number of anti-hypertensives, history of peripheral vascular disease, and baseline eGFR (R2 0.87), baseline foot insensitivity was associated with study-end eGFR (B = -3.551, p = 0.036). CONCLUSIONS: Patients with Type 2 diabetes and foot insensitivity are at increased risk of eGFR decline. Identifying these patients offers an opportunity to intensify metabolic and blood pressure control to prevent/retard the development of CKD. Future studies of larger sample size and longer follow up from multiple centres are needed to assess the diagnostic performance of our findings in predicting CKD development, and to compare the performance of the monofilament test with albuminuria.

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 (ß = -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.