ACTA ENDOCRINOLOGICA (BUC)

Context. Previous studies have demonstrated a correlation between creatinine and cystatin levels and thyroid disorders. Objective. To further investigate the diagnostic value of serum creatinine to cystatin C ratio in the diagnosis of thyrotoxicosis. Design. One hundred eighty four thyrotoxicosis patients and 406 healthy controls were enrolled. Subjects and Methods. We assessed at baseline characteristics, serum Cr:Cyc in thyrotoxicosis group, control group and subgroups and analyzed the relationship between the indicator and the etiology of thyroid gland toxicity. Results. Subgroup analysis indicated that the Cr:Cyc ratio in the Graves' disease (GD) group was lower than those in the Hashimoto's thyroiditis (HT) and subacute thyroiditis (SAT) groups (P<0.001). Correlation analysis demonstrated that the Cr:Cyc ratio was positively correlated with thyroid stimulating hormone (TSH) and thyrotropin receptor antibody (TRAb) but negatively correlated with free triiodothyronine (FT3) and free thyroxine (FT4) in the GD group. Receiver operating characteristic (ROC) curve analysis indicated that the area under the curve (AUC) value of the Cr:Cyc ratio for the diagnosis of thyrotoxicosis was 0.933 (P<0.001), and the AUC value for the diagnosis of GD was 0.778 (P<0.001). Conclusion. The Cr:Cyc ratio has clinical significance in the diagnosis of thyrotoxicosis and the identification of thyrotoxicosis etiology.