Cardiovascular outcomes in subclinical thyroid disease: an update

Area of Science:

• Endocrinology
• Cardiovascular Medicine
• Internal Medicine

Background:

• Subclinical thyroid disease is characterized by abnormal thyroid stimulating hormone (TSH) levels with normal circulating thyroid hormones.
• Both subclinical hypothyroidism (SCH) and subclinical hyperthyroidism (SCHr) have been associated with adverse cardiovascular outcomes.
• The therapeutic role of thyroid hormone and antithyroid treatments for subclinical thyroid disease is still under investigation.

Approach:

• Review of current literature on subclinical thyroid disease and cardiovascular outcomes.
• Analysis of findings regarding cardiovascular mortality in SCH, particularly in older adults.
• Examination of the relationship between SCHr and atrial fibrillation, including recent follow-up data.

Key Points:

• Cardiovascular disease is a significant factor in all-cause mortality for patients with SCH, especially those over 60.
• Levothyroxine treatment did not demonstrate a reduction in cardiovascular events or mortality in pooled clinical trials for SCH.
• While SCHr is linked to atrial fibrillation, mild SCHr in older adults showed no increased incidence over 5 years; however, SCHr may independently contribute to vascular disease via endothelial progenitor cell dysfunction.

Conclusions:

• The effect of treating subclinical thyroid disease on cardiovascular outcomes is not yet definitively established.
• Further prospective studies and clinical trials are necessary to clarify the benefits of treatment, particularly in younger patient cohorts.