Mean Platelet Volume in Graves’ disease: A Sign of Hypermetabolism Rather than Autoimmunity?

OBJECTIVE To evaluate the impact of mean platelet volume (MPV) on predicting disease course among patients with Graves' disease (GD). METHODS This retrospective study was performed between 2013-2016 at the Outpatient Endocrinology Clinic of Baskent University Faculty of Medicine, Adana hospital on 65 patients with GD. Among participants, 30 cases experienced thyrotoxicosis again during the first six months after discontinuing anti-thyroid drug (ATD) sessions that had been carried out for at least 12 months prior to stopping (Relapse group). We also observed 35 patients who exhibited normal thyroid functions within six months following ATD withdrawal (Remission group). MPV levels and thyroid function tests were recorded and total duration of ATD therapy was calculated for all participants. RESULTS The mean MPV level that was measured at the time of drug withdrawal did not differ between groups, being 8.0±1.2 fL in the Relapse group vs. 8.0±1.0 fL in the Remission group (p=0.81). However, we found that the relapse MPV was higher than the withdrawal MPV in the Relapse group (9.2±1.3 fL) than it was in the Remission group (8.0±1.2 fL, p=0.00). CONCLUSIONS Higher relapse MPV in Relapse group but similar MPV levels in both groups at ATD withdrawal may be attributed to hypermetabolism or hyperthyroidism rather than autoimmunity of GD. Abbreviations:BMI: Body mass index GD: Graves' disease MPV: Mean platelet volume TSH: Thyroid-stimulating hormone TRAbs: Thyrotropin receptor antibodies ATD: Anti-thyroid drug fT4: Free thyroxine fT3: Free triiodothyronine CBC: Complete blood count PTC: Papillary thyroid carcinoma.