Haemostatic profile in hypothyroidism as potential risk factor for vascular or thrombotic disease
Article first published online: 21 DEC 2001
European Journal of Clinical Investigation
Volume 31, Issue 2, pages 131–137, February 2001
How to Cite
Müller, B., Tsakiris, D. A., Roth, C. B., Guglielmetti, M., Staub, J.-J. and Marbet, G. A. (2001), Haemostatic profile in hypothyroidism as potential risk factor for vascular or thrombotic disease. European Journal of Clinical Investigation, 31: 131–137. doi: 10.1046/j.1365-2362.2001.00777.x
- Issue published online: 21 DEC 2001
- Article first published online: 21 DEC 2001
- Received 22 May 2000; accepted 20 October 2000
- Factor VII;
- hypercoagulable state;
- subclinical hypothyroidism;
- von Willebrand factor
The influence of thyroid failure on haemostasis is controversial, both hypocoagulable and hypercoagulable states have been reported. Since both subclinical and overt hypothyroidism have been associated with atherosclerosis, a hypercoagulable state in addition might represent a risk factor for thromboembolic disease.
We investigated various haemostatic variables in 42 women with subclinical hypothyroidism and compared them to 66 euthyroid controls. Prothrombin time, activated partial thromboplastin time, fibrinogen, factor VII activity (FVII:C), factor VII antigen (FVII:Ag), factor VIII activity, von Willebrand factor (vWF), antithrombin III, heparin cofactor II, protein C, protein S, plasminogen, antiplasmin, plasminogen activator inhibitor and tissue plasminogen activator, as well as common lipid variables, were measured.
Factor VII:C (P < 0·02) and the ratio FVII:C/FVII:Ag (P < 0·01) were significantly increased in subclinical hypothyroid patients compared to the control group. Both parameters remained higher in hypothyroid patients after exclusion of 18 women on oestrogen replacement therapy. No differences were found between the groups with respect to vWF or the other haemostatic and lipid variables tested.
Patients with subclinical hypothyroidism had significantly higher levels of FVII:C. The greater increase in FVII:C compared to that of FVII:Ag, as shown by the increase in their ratio, might reflect the presence of activated FVIIa. This might mean a hypercoagulable state, which could contribute to the increased prevalence of coronary heart disease reported in such patients. A hypercoagulable state might be another argument in favour of thyroxine replacement treatment in subclinical hypothyroidism, especially in patients with additional risk factors for vascular disease.