A Cross-Sectional Study on the Prevalence of Subclinical Hypothyroidism in Metabolic Syndrome Patients at a Tertiary...

Metabolic syndrome (MetS) is defined as a "constellation" of cardiometabolic risk factors, characterized by hypertension, atherogenic dyslipidemia, hyperglycemia, prothrombotic and proinflammatory conditions which, jointly, increase the risk of suffering cardiovascular diseases (CVD) and type 2 diabetes mellitus. Thyroid dysfunction is also believed to affect parameters such as high-density lipoprotein (HDL) cholesterol, triglycerides, plasma glucose, and blood pressure, in turn increasing the risk of CVD. Subclinical hypothyroidism (SCH), which independently raises the risk of CVDs and their associated complications, is more frequently detected in patients with MetS compared to the general population. When both conditions coexist, the risk of CVD and its complications is significantly heightened. The objective of the study was to find out the prevalence of SCH in patients with MetS.

A prospective cross-sectional study was conducted in the Department of General Medicine, New Civil Hospital, Surat, Gujarat, India. Eighty patients who fulfilled the criteria for MetS by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III), were taken into the study. A detailed history, anthropometric measurements, blood pressure, fasting blood glucose, lipid profile, and thyroid profile (Free T3, Free T4, and serum thyroid-stimulating hormone (TSH)) were undertaken. The thyroid profile was done by chemiluminescence immunoassay (CLIA) method.

Out of 80 patients with MetS, 48 were female and 32 were male, with the overall mean age of the study population being 46.5±9.5 years. Among them, 23.7% of the population was found to be having thyroid dysfunction. Among the thyroid dysfunction, SCH was highly prevalent (18.8%), 3.8% patients had overt hypothyroidism and 1.3% patients had subclinical hyperthyroidism. There were no overt hyperthyroid patients in our study. HDL (mg/dl) and TSH (mIU/L) were significantly higher in the SCH group as compared to other types of hypothyroidism group (p-value < 0.05).

There is a statistically significant prevalence of SCH (18.8%) in MetS patients. It is clear from the study that one-fifth of MetS patients or every fifth patient with MetS had SCH. Thus, looking proactively for SCH in MetS and treating it would prevent conversion to overt hypothyroidism and complications of MetS.