Hypothyroidism is Strongly Correlated with Mean Platelet Volume and Red Cell Distribution Width

Objective: Hypothyroidism is characterized with insufficient production and release of thyroid hormones, and cause a variety symptoms including cold intolerance, constipation, deceleration in movement, and hair loss. It is associated with increased inflammatory burden. Therefore, we aimed to observe red cell distribution width (RDW) and mean platelet volume (MPV) levels, novel predictors of inflammation, in patients with hypothyroidism and to compare to those in healthy subjects. Materials and Methods: The subjects with hypothyroidism that show up in internal medicine outpatient clinics of Abant Izzet Baysal University Hospital between January 2020 and January 2021 were enrolled to the retrospective study. Healthy volunteers were enrolled as control subjects. MPV and RDW of the study groups were compared. Results: The median RDW level of hypothyroid and control groups were 13.3 (10-20.7) % and 15.3 (11.8-21.3) %, respectively (p<0.001). The median MPV level of hypothyroid and control groups were 10.2 (6.4-12.4) fL and 8.1 (5.4-11.5) fL, respectively (p<0.001). MPV levels greater than 9.47 fL have 80% sensitivity and 72% specificity in predicting hypothyroidism (AUC: 0.66 [95% CI: 0.58-0.74]; p<0.001). RDW levels greater than 13.4% have 80% sensitivity and 50% specificity in predicting hypothyroidism (AUC: 0.67 [0.82 [95% CI: 0.59-0.75]; p<0.001). Conclusion: We suggest that elevated MPV and reduced RDW levels should alert physicians for hypothyroidism in otherwise healthy subjects. Keywords: Hypothyroidism, Red cell distribution width, Mean platelet volume, Inflammation, Thyroid hormones, Predictor, Retrospective study.