Hemostasis in Hypothyroidism and Autoimmune Thyroid Disorders.

Area of Science:

• Endocrinology
• Hematology
• Immunology

Background:

• Conflicting evidence exists regarding the impact of hypothyroidism on hemostasis and venous thromboembolism (VTE) risk.
• Limited population-based studies hinder clinical implications of hemostatic changes in hypothyroidism.

Purpose of the Study:

• To review laboratory and population-based findings on hemostatic alterations in hypothyroidism and autoimmune thyroid disorders.
• To assess the association between thyroid dysfunction and the risk of VTE.

Main Methods:

• A comprehensive literature search was performed using MEDLINE.
• Keywords included hypothyroidism, autoimmune thyroiditis, coagulation factors, hemostasis, and venous thromboembolism.
• Relevant papers on thyroid disorders and hemostasis were included in the review.

Main Results:

• Overt hypothyroidism is linked to a hypocoagulable state with decreased platelet count, aggregation, von Willebrand factor, and certain coagulation factors.
• Subclinical hypothyroidism and autoimmune thyroid disease show increased fibrinogen, factor VII, and plasminogen activator inhibitor-1, suggesting a hypercoagulable and prothrombotic state.
• Contradictory findings were noted across studies.

Conclusions:

• Overt hypothyroidism is associated with hypocoagulability, while subclinical and autoimmune thyroid disorders may promote a prothrombotic state.
• Conflicting results necessitate further investigation.
• Prospective studies are warranted to clarify VTE risk across different thyroid dysfunction levels.