The value of red blood cell distribution width in subclinical hypothyroidism.

OBJECTIVE Therefore, we evaluated the relationship between the subclinical hypothyroidism and red cell distribution width (RDW) levels in a healthy population. SUBJECTS AND METHODS The medical records of 23,343 consecutive health subjects were reviewed. Subjects were classified into four thyroid stimulating hormone (TSH) groups to determine the correlation between TSH and other variables in detail (0.3 to < 2.5 mU/L, 2.5 to < 5 mU/L, 5 to < 7.5 mU/L, and ≥ 7.5 mU/L). RESULTS In the multivariate linear regression analysis, RDW was associated with TSH levels, and e-GFR was inversely associated with TSH levels, respectively (standardized beta coefficient = 0.102, -0.019; p < 0.001, p < 0.001). After adjusting for age and sex, in the four groups, TSH levels were significantly correlated with RDW, estimated glomerular filtration rate (e-GFR), and free thyroxine (fT4) levels in all groups. Furthermore in the 4 th group, RDW levels were more strongly associated with TSH levels than in the other groups (p = 0.006). CONCLUSIONS RDW levels are correlated with euthyroid and subclinical thyroid status. Notably, RDW is more correlated with subclinical hypothyroidism than the euthyroid status. This study presents the relationship between the RDW levels and thyroid function using TSH level in a large healthy population.