Determination of platelet aggregation defcts by in vitro arachidonic acid and adenosin diphosphate induced aggregation tests in patients with thyroid dysfunction

Thyroid dysfunction is common in general population. The relationship between haemostasis and thyroid hormones has been known for years but the mechanisms haven't been clarified yet. In literature, it is shown that thyroid hormone levels effect primary haemostasis in many steps. In this study we evaluated the affect of thyroid dysfunction on platelet aggregation. Thirty seven patients who were diagnosed with hypothyroidism or hyperthyroidism between December 2013 and March 2014 and who did not received medical treatment yet were included in the study. Control group consisted 37 healthy persons. Thyroid function tests, complete blood count, platelet aggregation tests were studied in both patient and control group. Mean arachidonic acid and adenosin diphosphate induced platelet aggregation levels between patient and control groups and between hypothyroidy and hyperthyroidy groups were similar (p=0.053, p=0.546 and p=0.490, p=0.803). We found that age and platelet count effected the most arachidonic acid induced platelet aggregation levels. Arachidonic acid induced platelet aggregation levels decreased with age [B=-5,065; (95% Confidence interval: -9.165 – -0.966) p=0.016] and increased with platelet counts [B=0.0008; (%95 Confidence interval: 0,0001 – 0.002) p=0,029]. We found that the changes of adenosin diphosphate induced platelet aggregation levels were effected only by platelet counts and adenosin diphosphate induced platelet aggregation levels increased with platelet counts [B=0.0007; (%95 Confidence interval: 0.0001 – 0.0013) and p=0.024]. We found that thyroid dysfunction does not effect platelet aggregation alone if it does not change the levels of platelets. Age and platelet count were the main factors that effected arachidonic acid induced aggregation and platelet count was the main factor that effected adenosin diphosphat induced aggregation. Thyroid dysfunction does not effect arachidonic acid induced and adenosin diphosphat induced aggregation test. More studies are needed to detect the relationship between thyroid dysfunction and platelet aggregation.