Thyroid Feedback Quantile-based Index

Thyroid Feedback Quantile-based Index
Synonyms	TFQI, PTFQI
Reference range	–0.74 – +0.74
Test of	Sensitivity of TSH-producing pituitary cells to thyroid hormones; also a marker for the set point of thyroid homeostasis

The Thyroid Feedback Quantile-based Index (TFQI) is a calculated parameter for thyrotropic pituitary function. It was defined to be more robust to distorted data than established markers including Jostel's TSH index (JTI) and the thyrotroph thyroid hormone sensitivity index (TTSI).

How to determine the TFQI

The TFQI can be calculated with

${\displaystyle TFQI=F_{FT4}(FT4)-(1-F_{TSH}(TSH))}$

from quantiles of FT4 and TSH concentration (as determined based on cumulative distribution functions).^[1] Per definition the TFQI has a mean of 0 and a standard deviation of 0.37 in a reference population.^[1] This explains the reference range of –0.74 to + 0.74.

Reference range

Parameter	Lower limit	Upper limit	Unit
TFQI (PTFQI)	–0.74	+0.74

Clinical significance

Higher values of TFQI are associated with obesity, metabolic syndrome, impaired renal function, diabetes, and diabetes-related mortality.^{[1][2][3][4][5][6][7]} In a large population of community-dwelling euthyroid subjects the thyroid feedback quantile-based index predicted all-cause mortality, even after adjustment for other established risk factors and comorbidities.^[8]

A cross-sectional study from Spain observed increased prevalence of type 2 diabetes, atrial fibrillation, ischemic heart disease and hypertension in persons with elevated PTFQI.^[9]

Serum Concentrations of Adipocyte Fatty Acid-Binding Protein (A-FABP) are significantly correlateted to TFQI, suggesting some form of cross-talk between adipose tissue and HPT axis.^[10]

TFQI results are also elevated in takotsubo syndrome,^[11] potentially reflecting type 2 allostatic load in the situation of psychosocial stress. Reductions have been observed in subjects with schizophrenia after initiation of therapy with oxcarbazepine^[12] and quetiapine,^[13] potentially reflecting declining allostatic load.

Despite positive association to metabolic syndrome and type 2 allostatic load a large population-based study failed to identify an association to risks of dyslipidemia and non-alcoholic fatty liver disease (NAFLD).^[14]

See also

• Thyroid function tests
• Thyroid's secretory capacity
• Sum activity of peripheral deiodinases
• Jostel's TSH index
• Thyrotroph Thyroid Hormone Sensitivity Index

References

1. Laclaustra, M; Moreno-Franco, B; Lou-Bonafonte, JM; Mateo-Gallego, R; Casasnovas, JA; Guallar-Castillon, P; Cenarro, A; Civeira, F (February 2019). "Impaired Sensitivity to Thyroid Hormones Is Associated With Diabetes and Metabolic Syndrome". Diabetes Care. 42 (2): 303–310. doi:10.2337/dc18-1410. PMID 30552134.
2. "Schilddrüsenhormonresistenz und Risiko für Diabetes und metabolisches Syndrom". Diabetologie und Stoffwechsel. 14 (2): 78. 16 April 2019. doi:10.1055/a-0758-5718. S2CID 243074371.
3. Paschou, Stavroula A.; Alexandrides, Theodoros (19 October 2019). "A year in type 2 diabetes mellitus: 2018 review based on the Endorama lecture". Hormones. 18 (4): 401–408. doi:10.1007/s42000-019-00139-z. PMID 31630372. S2CID 204786351.
4. Guan, Haixia (April 2019). "Mild Acquired Thyroid Hormone Resistance Is Associated with Diabetes-Related Morbidity and Mortality in the General Population". Clinical Thyroidology. 31 (4): 138–140. doi:10.1089/ct.2019;31.138-140. S2CID 145947179.
5. Lou-Bonafonte, José Manuel; Civeira, Fernando; Laclaustra, Martín (20 February 2020). "Quantifying Thyroid Hormone Resistance in Obesity". Obesity Surgery. 30 (6): 2411–2412. doi:10.1007/s11695-020-04491-7. PMID 32078724. S2CID 211217245.
6. "甲状腺素抵抗与糖尿病和代谢综合征有关？看TFQI怎么说". www.medinfo-sanofi.cn. Retrieved 14 April 2020.^{[permanent dead link‍]}
7. Yang, S; Lai, S; Wang, Z; Liu, A; Wang, W; Guan, H (December 2021). "Thyroid Feedback Quantile-based Index correlates strongly to renal function in euthyroid individuals". Annals of Medicine. 53 (1): 1945–1955. doi:10.1080/07853890.2021.1993324. PMC 8567884. PMID 34726096.
8. Alonso, SP; Valdés, S; Maldonado-Araque, C; Lago, A; Ocon, P; Calle, A; Castaño, L; Delgado, E; Menéndez, E; Franch-Nadal, J; Gaztambide, S; Girbés, J; Chaves, F; Garcia-Serrano, S; Garcia-Escobar, E; Fernandez-García, JC; Olveira, G; Colomo, N; Rojo-Martínez, G (1 December 2021). "Thyroid hormone resistance index and mortality in euthyroid subjects: [e-mail] study". European Journal of Endocrinology. 186 (1): 95–103. doi:10.1530/EJE-21-0640. PMID 34735370. S2CID 243762070.
9. Alonso-Ventura, V; Civeira, F; Alvarado-Rosas, A; Lou-Bonafonte, M; Calmarza, P; Moreno-Franco, B; Andres-Otero, MJ; Calvo-Gracia, F; de Diego-Garcia, P; Laclaustra, M (26 July 2022). "A cross-sectional study examining the parametric thyroid feedback quantile index and its relationship with metabolic and cardiovascular diseases". Thyroid. 32 (12): 1488–1499. doi:10.1089/thy.2022.0025. PMC 9807248. PMID 35891590. S2CID 251103068.
10. Nie, X; Ma, X; Xu, Y; Shen, Y; Wang, Y; Bao, Y (December 2020). "Increased Serum Adipocyte Fatty Acid-Binding Protein Levels Are Associated with Decreased Sensitivity to Thyroid Hormones in the Euthyroid Population". Thyroid. 30 (12): 1718–1723. doi:10.1089/thy.2020.0011. PMID 32394790. S2CID 218600030.
11. Aweimer, A; El-Battrawy, I; Akin, I; Borggrefe, M; Mügge, A; Patsalis, PC; Urban, A; Kummer, M; Vasileva, S; Stachon, A; Hering, S; Dietrich, JW (12 November 2020). "Abnormal thyroid function is common in takotsubo syndrome and depends on two distinct mechanisms: results of a multicentre observational study". Journal of Internal Medicine. 289 (5): 675–687. doi:10.1111/joim.13189. PMID 33179374.
12. Zhai, D; Chen, J; Guo, B; Retnakaran, R; Gao, S; Zhang, X; Hao, W; Zhang, R; Zhao, Y; Wen, SW (1 December 2021). "Oxcarbazepine was associated with risks of newly developed hypothyroxinemia and impaired central set point of thyroid homeostasis in schizophrenia patients". British Journal of Clinical Pharmacology. 88 (5): 2297–2305. doi:10.1111/bcp.15163. PMID 34855997. S2CID 244818801.
13. Zhao, Y; Guan, Q; Shi, J; Sun, J; Wang, Q; Yang, J; Retnakaran, R; Han, J; Zhang, X; Hao, W; Huang, X; Zhang, R; Zhai, D; Wen, SW (15 February 2022). "Impaired central set point of thyroid homeostasis during quetiapine treatment in the acute phase of schizophrenia". Schizophrenia Research. 241: 244–250. doi:10.1016/j.schres.2022.02.010. PMID 35180663. S2CID 246830155.
14. Lai, S; Li, J; Wang, Z; Wang, W; Guan, H (2021). "Sensitivity to Thyroid Hormone Indices Are Closely Associated With NAFLD". Frontiers in Endocrinology. 12: 766419. doi:10.3389/fendo.2021.766419. PMC 8602917. PMID 34803928.