Evaluating the Chemerin‑to‑Deiodinase Ratio as a Novel TSH‑Independent Screening Marker for Adult Hypothyroidism: A Case‑Control Study

Abstract

Background: Hypothyroidism is currently diagnosed by thyroid‑stimulating hormone (TSH); however, TSH reflects central rather than peripheral thyroid function. There is a need for TSH‑independent biomarkers that reflect tissue metabolic changes. Methods: In a case‑control study (69 patients with newly diagnosed hypothyroidism and 66 with normal thyroid function, adults aged ≥16 years), we measured serum chemerin, deiodinase type I (DIO1), thyroid hormones, and lipids. The Chemerin‑to‑Deiodinase Ratio (CDR) was calculated. A receiver operating characteristic curve with bootstrap was used to evaluate diagnostic performance, and hierarchical logistic regression was used to measure the independent predictive value of the two components. Results: CDR was more than two-fold higher in hypothyroid patients (median 4.43 vs. 1.91, p < 0.0001) and was not correlated with TSH, T4, or T3. CDR was an independent predictor of hypothyroidism (p<0.001) in a fully adjusted model. CDR exhibited an AUC of 0.800 (95% CI 0.721‑0.872), with bootstrapped sensitivity of 89.9% and specificity of 62.1% at a cutoff >2.31. CDR was not an independent predictor of lipid concentrations. Conclusions: CDR is a new, TSH‑independent screening measure of hypothyroidism that combines peripheral adipokine and thyroid‑hormone‑activation abnormalities. Its high sensitivity suggests it may serve as a useful triage screening test.