Correlation between Subclinical Hypothyroidism and Metabolic Syndrome: A Retrospective Study

BACKGROUND: Several studies worldwide have studied the correlation between subclinical hypothyroidism (SCH), and metabolic syndrome (MetS), but have reported inconsistent findings. OBJECTIVES: To assess the correlation between SCH and MetS in a population from Saudi Arabia. METHODS: This retrospective study was conducted at King Abdulaziz University Hospital and analyzed all thyroid function tests conducted between January 1, 2019, to December 31, 2021. A predesigned checklist was used to collect data about patients’ characteristics such as age, gender, nationality, TSH, FT4 level, and MetS components. RESULTS: A total of 41,519 thyroid function tests were conducted during the study period. From this, 1303 (3.1%) patients were found to have SCH, with the majority being females (74.4%). The prevalence did not differ according to gender but increased to 3.5% among those aged >60 years. MetS components between mildly and markedly elevated TSH were significant for total cholesterol (P < 0.001) and high-density lipoprotein cholesterol (P < 0.05). Male patients with SCH were at a higher risk of developing diabetes (P < 0.001) and hypertension (P < 0.02), than female patients with SCH. After adjusting for age, in the multiple stepwise linear regression analysis, a significant association was found between TSH levels and ALT (odds ratio: 0.77) and SBP (odds ratio: 0.35). CONCLUSION: The study demonstrated that the prevalence of SCH is similar between both genders but increases with age. MetS components were abnormal in patients aged >50 years and in males with SCH. SCH and MetS components were found to be correlated, and thus monitoring these variables in patients with SCH is advisable.