Prospective Evaluation of Coexistence of Subclinical Hypothyroidism with Type 2 Diabetes Mellitus and Its Effect on Metabolic Profile

Abstract

BACKGROUND Subclinical hypothyroidism is the term used to describe a condition where there is isolated elevated serum thyroid stimulating hormone level in the setting of normal serum free thyroxin levels in the absence or presence of symptoms. There is no uniformity in various studies regarding association between subclinical hypothyroidism and type 2 diabetes mellitus with regard to prevalence and change in metabolic profile. METHODS After enrolment of patients, a detailed relevant history of patients was taken and detailed clinical examination was done. All information obtained from patients was recorded in predesigned proforma. After 8 hours of fasting, serum levels of glucose, HbA1c, total cholesterol, high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) by fully automated clinical biochemistry analyser EM 200 were checked. Serum free T3, free T4 and thyroid stimulating hormone (TSH) were measured using standard assay. RESULTS Fasting glucose was significantly higher (P = .00001) in diabetes mellitus plus subclinical hypothyroidism group than patients with diabetes mellitus (DM) and euthyroid group (156.3 + 15.77 mg / dl vs. 128.1 + 21.44 mg / dl). Fasting insulin was significantly higher (P = .00001) in diabetes mellitus plus subclinical hypothyroidism group than patients with DM and euthyroid group (3.69 + 0.82 mu / L vs. 2.36 + 0.75 mu / L). There was no significant difference between two groups regarding HbA1c. CONCLUSIONS From our study we conclude that prevalence of subclinical hypothyroidism was higher in type 2 diabetes patients than normal population and there was female predominance. Body mass index was significantly higher in subclinical hypothyroidism group and there was no significant difference between the two groups regarding duration of diabetes mellitus. Patients with subclinical hypothyroidism have poor glycaemic control. KEYWORDS Subclinical Hypothyroidism, Diabetes Mellitus, Metabolic Profile