Cardiovascular Risk Assessment in Subclinical Hypothyroid Individuals with Thyroid-stimulating Hormone <10 uIU/ml

Area of Science:

• Cardiology
• Endocrinology
• Medical Imaging

Background:

• Subclinical hypothyroidism (SCH) is characterized by elevated serum thyroid-stimulating hormone (TSH) with normal free thyroid hormone levels.
• The cardiovascular risk associated with SCH, particularly with TSH levels below 10 uIU/ml, remains unclear.
• Epicardial fat thickness (EFT) is an emerging marker for cardiovascular risk.

Purpose of the Study:

• To investigate the cardiovascular risk in individuals with subclinical hypothyroidism (TSH <10 uIU/ml) using epicardial fat thickness (EFT) measurements.
• To explore the correlation between TSH levels and EFT in this population.

Main Methods:

• A cross-sectional study involving 35 cases of subclinical hypothyroidism (TSH <10 uIU/ml) and 35 matched controls.
• Epicardial fat thickness (EFT) was assessed by a single cardiologist for all participants.
• Statistical analysis included correlation, subgroup analysis, and receiver operating characteristic (ROC) curve analysis.

Main Results:

• Median EFT was significantly higher in subclinical hypothyroid cases (3.8 mm) compared to controls (2.6 mm) (P = 0.0002).
• A moderate positive correlation (r=0.561) was observed between TSH levels and EFT.
• Higher EFT was noted in the TSH subgroup of ≥7.6 to <10 uIU/ml, and both TSH and LDL were associated with high EFT (>4 mm).
• ROC analysis indicated acceptable discriminatory power for TSH and LDL in predicting EFT >4 mm.

Conclusions:

• Individuals with subclinical hypothyroidism (TSH <10 uIU/ml) exhibit significantly increased epicardial fat thickness compared to euthyroid controls.
• A positive correlation exists between TSH levels and EFT, suggesting EFT as a potential indicator of cardiovascular risk in SCH.
• TSH and LDL are associated with increased EFT, highlighting their role in cardiovascular risk stratification in subclinical hypothyroidism.