Abstract: Objective To study the changes in platelet volume indices in patients with Graves’ disease(GD) before and after therapy. Methods From July 2009 to Dec. 2009, 275 patients with GD were enrolled in this study, 199 patients were euthyroid(Euthyroid group), 99 patients were still hyperthyroid(Hyperthyroid group). Platelet count(PLT), mean platelet volume(MPV), platelet distribution width(PDW), platelet-large cell ratio(P-LCR) and changes of mean platelet volume(△MPV) and platelet-large cell ratio(△P-LCR) were measured. Results Before therapy, compared to patients with euthyroid state, MPV and P-LCR were significantly lower in patients with hyperthyroid state. After therapy, MPV, PDW and P-LCR were significantly higher in the hyperthyroid group. Before and after therapy in two groups, PDW, △MPV and △P-LCR were significantly different(P<0.01). P-LCR was higher than 24.85% before therapy and lower than 30.55% after therapy, which suggest that GD patients may have been in euthyroid state after therapy. Conclusion GD patients achieved euthyroid state after treatment, there were falls in MPV, PDW and P-LCR than before. There were significant differences in PDW, △MPV and △P-LCR in the two groups before and after therapy. P-LCR suggested that the therapy may be effective and it maybe features of GD that have not previously been described.

Key words: hyperthyroidism, Graves disease, platelet volume indices, platelet-large cell ratio