The Relationship Between Serum Sodium And Diabetic Peripheral Neuropathy In Type 2 Diabetes Mellitus

Objective: Diabetes is often complicated with hyponatremia. The relationship between serum sodium level and diabetic peripheral neuropathy is unknown. The aim of this study is to investigate the relationship between serum sodium level(including normal range) and diabetic peripheral neuropathy in patients with type 2 diabetes mellitus.Methods: This study is a retrospective investigation, included 930 participants with type 2 diabetes,excluded other neuropathy and severe complications of patients. According to the results of the nerve conduction studies, determine whether there is diabetic peripheral neuropathy, a total of 331 patients with DPN, and 599 patients without DPN. Collect patients' generally baseline information, glycosylated hemoglobin(Hb A1c), blood glucose, blood lipid, serum sodium, urinary albumin creatinine ratio, estimated glomerular filtration rate and other biochemical indicators. Through the nerve conduction studies(EMG), a total of patients were measured the motor nerve conduction velocity(MCV) of median nerve, ulnar nerve, tibial nerve,phil total nerve, and the sural nerve conduction velocity(SCV) of median nerve, ulnar nerve, phil shallow nerve and sural nerve, and the corresponding motor nerve conduction amplitude(MAMP), sensory nerve conduction amplitude(SAMP). SPSS18.0 software was used for statistical analysis of research data. Multi-factor method was used to analyze the correlation between serum sodium level and nerve conduction velocity, nerve conduction amplitude. Binary logistic regression and the forest figure were used to analyze the relationship between serum sodium level and DPN.Results: Hyponatremia group had a higher detection rate of DPN(56.4%) VS non hyponatremia group(34.7%)(P =0.006). With a decrease of serum sodium level, the prevalence of DPN rose, and the nerve CV gradually declined. Even in normal range of serum sodium level, this trend still existed. Multivariate tests indicated that there were significant differences in nerve conduction velocity of different level of serum sodium groups. Excepted the composite motor nerve conduction amplitude vector(Composite MAMP), the composite motor nerve conduction velocity vector(Composite MCV), the composite sensory nerve conduction velocity vector(Composite SCV) and the composite sensory nerve conduction amplitude vector(Composite SAMP) were statistically significant. Logistic regression analysis showed that the negative relationship between serum sodium level and DPN was still independence related after adjustment for age, gender, duration of DM, BMI [OR = 0.915(0.870-0.962), P < 0.001]. And this relationship still had statistical significance after further adjustment for systolic and diastolic blood pressure, Hb A1 c, e GFR, serum potassium level [OR=0.940(0.888-0.995),P=0.032], and adjusting for antihypertensive drugs, hypoglycemic drugs, hypertension, smoking and drinking [OR=0.931(0.875-0.990),P=0.023]. The relationship between normal range of serum sodium and DPN was independence related after adjustment for age, gender, duration of DM, BMI [OR = 0.923(0.862 0.988), P = 0.021]. But there was no statistical significance after further adjustment. Subgroup analysis found that, the significant correlation between serum sodium and DPN was incarnated by different groups of gender and age, long duration(duration of diabetes ? 10 years), non-obese patients(BMI < 24 kg / m2), Hb A1 c < 7% and ACR ?30mg/g. In normal range of serum sodium, the correlation was incarnated by age<65, duration of diabetes ? 10 years, BMI < 24 kg / m2.Conclusions: Hyponatremia is one of the risk factors of DPN, even in normal range of serum sodium level, this trend still exists. Hyponatremia could be a potential biomarker for DPN.