Diabetic Peripheral Neuropathy Associated With Urinary Albumin-to-Creatinine Ratio And Estimated Glomerular Filtration Rate In Type 2 Diabetics

Background: Diabetic Peripheral Neuropathy(DPN) has been shown to be associated with renal function. We aimed to investigate the potential association between urinary albumin-to-creatinine ratio(UACR) and estimated glomerular filtration rate(e GFR) and DPN. We were especially interested in the relationship between normal or mildly abnormal UACR and e GFR with DPN.Methods: A retrospective study was performed in 1059 patients with type 2 diabetes(589 male patients and 470 female patients) from the First Affiliated Hospital of Fujian Medical University between June 2010 and September 2014. DPN was documented by nerve conduction function tests. There are 417 DPNs and 642 non-DPNs in the total group. Patients' baseline data such as gender, age, course of the disease, use of drugs, and some biochemical indicators such as urinary albumin-to-creatinine ratio, estimated glomerular filtration rate, serum creatinine, uric acid, blood lipids, glycosylated hemoglobin have been collected. Ulnar, median, sural, and peroneal nerve conduction velocities(NCVs) were performed on each subject using EMG.Results:1. The DPN population demonstrated higher UACR [54.65(12.11-472.45)mg/g VS 9.18(5.35-22.70)mg/g, P=0.000], lower e GFR[89.61(65.41-108.53)ml/min/1.73m2 VS 104.43(88.63-124.69)ml/min/1.73m2,P=0.000] than the non-DPN population.2. With the increase of UACR and the decrease of e GFR, the NCVs decreased and the prevalence of DNP increased, even though they were in the normal or mildly abnormal UACR and e GFR groups.3. After adjusted for age, gender, course of disease, blood pressure, body mass index(BMI), glycated hemoglobin A1c(Hb A1c), fasting plasma glucose(FPG), uric acid(UA), and history of diabetic retinopathy, diabetic foot, smoking, drinking and medication, NCVs were negatively correlated with UACR, and were positively correlated with e GFR. Even in UACR<30mg/g and e GFR?60 ml/min/1.73m2 groups, this correlation still existed in varying degrees.4. UACR and e GFR were independently associated with the risk of DPN(OR=3.143, 95%CI=2.427-4.069, P<0.001; OR=2.616, 95%CI = 2.000- 3.423, P<0.000). Even in the UACR<30mg/g and e GFR?60 ml/min/1.73m2 groups, the relationship above still existed and patients in the highest tertiles of UACR and lowest tertiles of e GFR demonstrated a greater risk of DPN(OR=2.456, 95%CI=1.461-4.127, P=0.001; OR=2.021, 95%CI=1.276-3.203, P=0.003).5. Receiver-operating characteristic(ROC) analysis revealed that the area under curve(AUC) of UACR, e GFR, and joints indicate DPN was 0.749, 0.662, and 0.731 respectively. Sensitivity was 62.00%, 47.40%, 55.30% respectively, while specificity was 75.0%, 77.3%, 81.5% respectively.Conclusions: Lower e GFR and higher UACR were associated with the risk of DPN, even though normal or mildly abnormal UACR and e GFR has already been an indicator of DPN. Furthermore, UACR is more sensitive than e GFR. Separately, UACR was a moderate indication of DPN, and combining it with e GFR didn't increase its effect of indication to DPN.