The Association Between Thyroid Hormone Sensitivity Index And Diabetic Peripheral Neuropathy

Objective: To investigate the correlation between thyroid hormone sensitivity index and diabetic peripheral neuropathy(DPN).Methods: A total of 217 patients with type 2 diabetes(T2D)who were hospitalized in the Department of Endocrinology,the First Affiliated Hospital of University of Science and Technology of China from October 2020 to September 2022 were enrolled in this study.The clinical data of age,gender,course of disease,height,weight,blood pressure and so on were collected.Fasting venous blood of patients was collected in the morning to detect glycosylated hemoglobin A1c(Hb A1c),fasting blood glucose(FBG),triglyceride(TG),total cholesterol(TC),free triiodothyronine(FT3),free thyroxine(FT4),thyroid stimulating hormone(TSH),serum creatinine(Cr)and other indicators.Central thyroid hormone sensitivity was assessed by calculating thyroid feedback quantile index(TFQI),TSH index(TSHI)and thyroid hormone resistance index(TT4RI).Peripheral thyroid hormone sensitivity was assessed by FT3/FT4 ratio.All patients were divided into DPN group and non-DPN group according to symptoms,signs and neuroelectrophysiological examination.Independent sample t test and MannWhitney U test were used to compare the measurement data between the two groups,and chi-square test was used to analyze the count data.The relationship between thyroid hormone sensitivity and Toronto clinical neuropathy score(TCSS),the incidence of DPN and various clinical indicators was analyzed by Pearson correlation analysis.Multiple linear regression analysis was used to explore the influencing factors of thyroid sensitivity index.Logistic regression analysis was used to evaluate the influencing factors of DPN,and the correlation between thyroid hormone sensitivity index and the incidence of DPN was analyzed.ROC curve analysis had diagnostic value for DPN.Results: 1.The FT3/FT4 ratio in DPN group was lower than that in non-DPN group(P=0.04).Compared with the non-DPN group,patients in the DPN group were older,had longer disease duration,and had higher TC levels(all P<0.05).2.Pearson correlation analysis showed that TT4 RI was negatively correlated with FBG and ulnar nerve motor nerve conduction velocity(all P<0.05),and positively correlated with median nerve motor nerve conduction velocity and common peroneal nerve motor nerve conduction velocity(all P<0.05).TFQI was positively correlated with motor nerve conduction velocity of median nerve,motor nerve conduction velocity of common peroneal nerve and sensory nerve conduction velocity of median nerve(all P<0.05).TSHI was negatively correlated with motor nerve conduction velocity of median nerve,motor nerve conduction velocity of common peroneal nerve and motor nerve conduction velocity of common peroneal nerve(all P<0.05).FT3/FT4 ratio was negatively correlated with TCSS(P=0.001).3.Multiple linear regression analysis showed that FT3/FT4 ratio was associated with DPN(P=0.031).4.Logistic regression model showed that FT3/FT4 ratio(OR=0.062,95%CI: 0.006-0.587),duration of diabetes(OR=1.996,95%CI: 1.268-3.142)and TC(OR=0.176,95%CI: 0.060-0.513)were the independent influencing factors for the incidence of DPN.5.ROC curve showed that FT3/FT4 ratio had certain diagnostic value for DPN.Conclusion: Thyroid hormone sensitivity index is associated with DPN in T2 D patients.The central thyroid hormone sensitivity index TT4 RI,TFQI and TSHI are related to abnormal nerve conduction velocity,and the peripheral thyroid hormone sensitivity index FT3/FT4 ratio is an influencing factor for the incidence of DPN.