MEAN PLATELET VOLUME LEVELS IN PATIENTS WITH OVERT HYPOTHYROIDISM BEFORE AND AFTER LEVOTHYROXINE TREATMENT

Objective. Hypothyroidism accelerates atherosclerosis and thyroid hormone replacement inhibits this progression. Platelet activation and aggregation play major role in the pathophysiology of atherothrombosis. Mean platelet volume (MPV), a determinant of platelet function, is a newly emerging risk factor for atherosclerosis. The present study was designed to evaluate levels of MPV before and after the levothyroxine (LT4) treatment in patients with overt hypothyroidism. Design. The study included 30 Hashimoto's thyroiditis patients with overt hypothyroidism and 20 healthy control subjects. Hypothyroid patients were given LT4 replacement therapy. Fasting glucose, lipid levels and blood counts were assessed before and after the maintenance of euthyroidism. Results. Fasting glucose, platelet count and all lipid parameters were similar between the two groups. The mean MPV level of hypothyroid patients was hither than of the control group (p<0.01). A significant decrease in the mean MPV level was detected after the maintenance of euthyroidism with LT4 treatment (p<0.05). Conclusion. This study suggests that patients with overt hypothyroidism tend to have increased platelet activation. This activation may cause increased risk of atherothrombotic complications that may be reversed by treatment of hypothyroidism.