Hemostasis in Overt and Subclinical Hyperthyroidism

Area of Science:

• Endocrinology
• Hematology
• Thrombosis Research

Background:

• Conflicting data exists regarding hyperthyroidism's impact on hemostasis.
• Limited population-based studies hinder understanding of clinical implications, particularly venous thromboembolism (VTE) risk.
• This review examines hemostatic alterations in both overt and subclinical hyperthyroidism.

Purpose of the Study:

• To review and synthesize current knowledge on hemostatic changes in hyperthyroidism.
• To evaluate the potential link between hyperthyroidism and an increased risk of VTE.

Main Methods:

• A systematic literature search was performed using the MEDLINE database.
• Keywords included hyperthyroidism, thyrotoxicosis, Graves disease, goiter, hemostasis, coagulation factors, blood coagulation disorders, VTE, bleeding, and fibrinolysis.
• Relevant articles linking hyperthyroidism and hemostasis were included.

Main Results:

• Hyperthyroidism, both overt and subclinical, is generally associated with a hypercoagulable state.
• This may stem from elevated levels of coagulation factors (e.g., FVIII, FX, FIX, vWF, fibrinogen).
• Hypofibrinolysis is also observed, indicated by decreased plasmin/plasmin activator or increased PAI-1 and TAFI.

Conclusions:

• While many studies suggest a hypercoagulable state in overt hyperthyroidism at a biochemical level.
• The clinical significance of these findings regarding the actual occurrence of VTE remains unconfirmed.