CONSEQUÊNCIAS CARDIOMETABÓLICAS DO HIPOTIREOIDISMO SUBCLÍNICO: MECANISMOS FISIOPATOLÓGICOS E IMPLICAÇÕES TERAPÊUTICAS DA LEVOTIROXINA

• DOI: https://doi.org/10.22533/at.ed.8208182509103

• Palavras-chave: Hipotireoidismo Subclínico; Levotiroxina; Doenças Cardiovasculares; Metabolismo; Terapia Hormonal.

• Keywords: Subclinical Hypothyroidism; Levothyroxine; Cardiovascular Diseases; Metabolism; Hormone Therapy.

• Abstract: Introduction: Subclinical hypothyroidism is defined by elevated serum TSH levels with normal free T4 concentrations. Although often asymptomatic, it has relevant physiological repercussions, particularly on cardiovascular and metabolic systems. Alterations in myocardial contractility, peripheral vascular resistance, and lipid metabolism have been widely reported, indicating progressive cardiac impairment and increased atherosclerotic risk. Methods: A narrative review was conducted using PubMed, Scopus, and Web of Science databases, including studies published between 2019 and 2024. Clinical trials, meta-analyses, and systematic reviews addressing the relationship between subclinical hypothyroidism, cardiovascular dysfunction, and levothyroxine treatment were included. Results: Evidence indicates that subclinical hypothyroidism is associated with diastolic dysfunction, ventricular hypertrophy, atherogenic dyslipidemia, and elevated inflammatory markers. Levothyroxine therapy demonstrated moderate benefits in lipid profile, cardiac function, and insulin sensitivity, particularly in patients with TSH >10 mIU/L or increased cardiovascular risk. However, findings remain controversial in elderly or asymptomatic individuals, where overtreatment may induce adverse effects such as tachyarrhythmias and bone loss. Conclusion: Subclinical hypothyroidism significantly affects cardiometabolic homeostasis. Levothyroxine therapy should be individualized, balancing potential benefits and risks according to patient age, cardiovascular status, and comorbidities.