John Yango, Orsalia Alexopoulou, Stephane Eeckhoudt, Cedric Hermans and Chantal Daumerie
Several hemostatic abnormalities have been described in hypothyroidism, such as modification of coagulation proteins and bleeding tendency. Although thyroid hormone deficiency is considered to be responsible for these changes, the underlying mechanisms have not yet been established.
To evaluate the respective influence of peripheral thyroid hormones (free thyroxine) and TSH on blood clotting by assessing coagulation parameters in patients with a history of total thyroidectomy for thyroid cancer, under three different conditions: induced hypothyroidism, euthyroid state, and following recombinant human TSH (rhTSH) administration.
Coagulation parameters (platelet count, fibrinogen, international normalized ratio, prothrombin time, thrombin time, activated partial thromboplastin time (APTT), factor VIII activity ((FVIII:C), as well as von Willebrand factor antigen (VWF:Ag) and VWF activity using collagen binding assay (VWF:CBA)) were measured in patients with severe hypothyroidism following withdrawal of thyroid hormone replacement therapy, and in the same patients with euthyroidism after restoring replacement treatment (group A), and before and after administering rhTSH (group B).
FVIII:C, VWF:Ag, and VWF:CBA were significantly decreased (P<0.001), whereas APTT was significantly increased (P<0.001) in patients with severe hypothyroidism compared with patients in the euthyroid state. No changes in clotting parameters were observed in patients who received rhTSH therapy.
This prospective study shows that severe short-term hypothyroidism is associated with significantly lower levels of VWF:Ag, VWF:CBA, and FVIII:C. Administration of exogenous TSH has no effect on coagulation parameters. These findings suggest that thyroid hormone deficiency is likely to be the main cause of coagulation alterations in patients with hypothyroidism.
Luigi Bartalena, Lelio Baldeschi, Alison Dickinson, Anja Eckstein, Pat Kendall-Taylor, Claudio Marcocci, Maarten Mourits, Petros Perros, Kostas Boboridis, Antonella Boschi, Nicola Currò, Chantal Daumerie, George J Kahaly, Gerasimos E Krassas, Carol M Lane, John H Lazarus, Michele Marinò, Marco Nardi, Christopher Neoh, Jacques Orgiazzi, Simon Pearce, Aldo Pinchera, Susanne Pitz, Mario Salvi, Paolo Sivelli, Matthias Stahl, Georg von Arx and Wilmar M Wiersinga
Wilmar Wiersinga, Miloš Žarković, Luigi Bartalena, Simone Donati, Petros Perros, Onyebuchi Okosieme, Daniel Morris, Nicole Fichter, Jurg Lareida, Georg von Arx, Chantal Daumerie, Maria-Christina Burlacu, George Kahaly, Susanne Pitz, Biljana Beleslin, Jasmina Ćirić, Goksun Ayvaz, Onur Konuk, Füsun Balos̜ Törüner, Mario Salvi, Danila Covelli, Nicola Curro, Laszlo Hegedüs, Thomas Brix and EUGOGO (European Group on Graves’ Orbitopathy)
To construct a predictive score for the development or progression of Graves’ orbitopathy (GO) in Graves’ hyperthyroidism (GH).
Prospective observational study in patients with newly diagnosed GH, treated with antithyroid drugs (ATD) for 18 months at ten participating centers from EUGOGO in 8 European countries.
348 patients were included with untreated GH but without obvious GO. Mixed effects logistic regression was used to determine the best predictors. A predictive score (called PREDIGO) was constructed.
GO occurred in 15% (mild in 13% and moderate to severe in 2%), predominantly at 6–12 months after start of ATD. Independent baseline determinants for the development of GO were clinical activity score (assigned 5 points if score > 0), TSH-binding inhibitory immunoglobulins (2 points if TBII 2–10 U/L, 5 points if TBII > 10 U/L), duration of hyperthyroid symptoms (1 point if 1–4 months, 3 points if >4 months) and smoking (2 points if current smoker). Based on the odds ratio of each of these four determinants, a quantitative predictive score (called PREDIGO) was constructed ranging from 0 to 15 with higher scores denoting higher risk; positive and negative predictive values were 0.28 (95% CI 0.20–0.37) and 0.91 (95% CI 0.87–0.94) respectively.
In patients without GO at diagnosis, 15% will develop GO (13% mild, 2% moderate to severe) during subsequent treatment with ATD for 18 months. A predictive score called PREDIGO composed of four baseline determinants was better in predicting those patients who will not develop obvious GO than who will.