Prevalence of Thyroid Disorders in Patients with Type 2 Diabetes Complicated with Diabetic Neuropathy

Abstract Background Diabetic peripheral neuropathy(DPN) is the most common complication of Type 2 diabetes mellitus (T2DM), affecting as many as 50% of diabetic patients. Thyroid dysfunction and diabetes mellitus are closely linked. Several studies have documented the increased prevalence of thyroid disorders particulary hypothyroidism in patients with diabetes mellitus and vice versa. Recent studies have shown that free triiodothyronine (fT3), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) levels have been linked to insulin resistance and chronic complications of diabetes particulary DPN. Aim of work: This study aims to investigate the prevalence of thyroid dysfunction in patients with type 2 diabetes mellitus complicated with diabetic peripheral neuropathy. Patients and Methods This study was a cross sectional study that was conducted at Diabetes outpatient clinic at Ain Shams university Hospital. This study was performed on 250 patients with type 2 diabetes with diabetic peripheral neuropathy aging from 18 to 60 years old not known to have thyroid dysfunction, with a clinical diagnosis of diabetes (type 2) and diabetic peripheral neuropathy. All candidates were subjects to full history, full clincal, neurological and thyroid examination and laboratory investigations (Fasting blood glucose, 2hrs post prandial, HbA1c, lipid profile. Tsh, ft3,ft4, alb/cr ratio, Alt, Ast, urea, creatinine, urine analysis and thyroid U/S if needed). Results Among the studied 250 patients, 192 (76.8%) patients have Normal thyroid status, 58 (23.2%) patients have thyroid dysfunction distributed as the following : 23 (9.2%)patients with Subclinical Hypothyrodism, 19 (7.6%) patients with Hypothyrodism, 7 (2.8%)patients withSubclinical hyperthyroidism and 9 (3.6%) patients with Hyperthyrodism. Regarding the DPN grade, 43 (17.2%) patients have Mild DPN, 167(66.8%) patients have Moderate DPN and 40(16.0%) patients have DPN according to DPN grade using the known questionnaire of neuropathy (total ssympto NTSS-6 questionnaire). Among the studied population 79 (31.6%)patients are males while 171(68.4%) are females and their ages ranged from 35 to 64 years (mean 52.11 years), The Mean BMI was 27.59 ± 3.77kg/m2. Among patients with Thyroid Dysfunction There were statistically significant difference between Severity of DPN and Thyroid function tests. Among patients with thyroid dysfunction, moderate DPN was the most prevelant47/58patients (81.0%)followed by mild DPN 8/58 patients (13.8%) and the least was severe DPN 3/58 patients (5.2%). Also Among the euthyroid patients, moderate DPN was the most frequent 120/192 patients (62.5%),but followed by severe DPN 37/192 patients (19.3%) and the least was mild DPN 35/192 patients (18.2%). (P value = 0.015) There were highly statistically significant difference between patients with normal Thyroid status and patients with Thyroid dysfunction regarding Cholesterol (P value=0.000), Triglyceride (P value = 0.000) and LDL (P value = 0.001) being higher in those with thyroid dysfunction, and there were statistically significant difference between patients with normal thyroid status and patients with thyroid dysfunction regarding Alb/cr R (p value=0.034), and there were no statistically significant difference between patients with normal Thyroid status and Thyroid dysfunction regarding FBG(mg/dl), 2hrs PP(mg/dl), Hba1c(%), FT3(pg/ml), FT4(ng/dl) and HDL (mg/dl) Conclussions Thyroid dysfunction mainly subcinical hypothyroidism is more prevalent among T2DM subjects with DPN.