VARIATION TENDENCY OF COAGULATION PARAMETERS IN DIFFERENT HYPOTHYROIDISM STAGES.

The hemostatic balance is a complex system where the delicate equilibrium is regulated by several factors including hormones. Hypothyroidism, as a common disease in the general population, affects both the coagulation and fibrinolytic systems. However, the reliable clinical evidence is so far lacking and published data remain conflicting. According to the severity of the disease, we divided all study subjects into four groups: 50 controls, 47 patients displaying subclinical hypothyroidism, 41 patients displaying moderate hypothyroidism (TSH≤50 mU/L), and 53 patients displaying severe hypothyroidism (TSH>50 mU/L). We investigated various coagulation parameters including: activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen (FIB) and international normalized ratio(INR). Compared with control subjects, patients with subclinical hypothyroidism displayed hypercoagulability, as reflected by shorter APTT levels and increased FIB levels. The patients with moderate hypothyroidism had only increased TT levels without any significant variation in the other studied parameters, which suggested neither obvious bleeding tendency nor clotting tendency. The patients with severe hypothyroidism displayed a bleeding tendency, as reflected by higher APTT, PT, TT, INR levels and decreased FIB levels. The patients with different hypothyroidism stages display various abnormalities of coagulation.