Significant losses of functional proteins such as hormones and hormone-binding proteins are seen in patients suffering from proteinuria. Studies have reported loss of thyroid hormones and thyroxine-binding globulin in the urine. There is evidence that subclinical hypothyroidism is six times more common in patients with proteinuria than in healthy people. The parameters of the effect of proteinuria on thyroid function have not been fully studiedyet.We investigated 74 patients with qualitatively established proteinuria, of whom 34 men and 40 women, without diagnosed thyroid disease. The average age of the patients was 60.9 years. We tested 20 free controls for free thyroxine (FT4), thyroid stimulating hormone (TSH), creatinine and albumin in serum, and the quantity of urine protein. The mean results found for TSH were higher in the patients with proteinuria than in those of the controls (2.719 mU/l vs 1.78 mU/l). For FT4, the mean result in the patients with proteinuria was 17.04 pmol/l vs 16.39 pmol/l. in the controls. A correlation was sought between TSH and FT4 levels and all the laboratory parameters we tested. Patients with proteinuria had higher TSH levels, probably due to the loss of thyroid hormones in the urine. However, these losses cannot lead to clinically proven hypothyroidism.
1. Branten AJW, Bufvereijken PW, KlasenIS, Bosch FH, Feith GW, HollanderDA, et al. Urinary excretion of β2-microglobulin and IgG predict prognosis in idiopathic membranous nephropathy: a validation study. J Am Soc Nephrol. 2005;16:169-74.
2. Gilles R, den Heijer M, Ross AH, Sweep FC, Hermus AR, Wetzels JF. Thyroid function in patients with proteinuria. Netherlands J Med. 2008;66(11):483-5.
3. Mariani LH,Berns JS.The Renal Manifestations of Thyroid Disease. J Am Soc Nephrol. 2012;23(1):22-26.
4. Saini V, Yadav A, Kataria M, AroraAS, Singh R. Correlation of creatinine with TSH levels in overt hypothyroidism - a requirement for monitoring of renal function in hypothyroid patients? Clin Biochem.2012;45(3):212-4.
5. Mansournia N, Riyahi S, Tofangchiha S, Mansournia MA, Riahi M, Heidari Z, et al.Subclinical hypothyroidism and diabetic nephropathy in Iranian patients with type 2 diabetes.J Endocrinol Invest.2017;40 (3):289- 295.
6. Xin Du, Binbin Pan, Wenwen Li, Yonghua Zou,Xi Hua, Wenjuan Huang, et al. Albuminuria is an independent risk factor of T4 elevation in chronic kidney disease.Sci Rep. 2017;7:41302. doi: 10.1038/srep41302.
9. Afroz S, KhanAH, Roy DK. Thyroid function in children with nephrotic syndrome. Mymensingh Med J. 2011;20(3):407-11.
10. Kapoor K, Saha A, Dubey NK. Subclinical no autoimmune hypothyroidism in children with steroid resistant nephritic syndrome. Clin Exp Nephrol. 2014;18(1):113-7.
11. Hoogendoorn EH, Hermus AR, de Vegt F, Ross HA, Verbeek AL, Kiemency LA, et al. Thyroid function and prevalence of anti-thyroperoxidase antibodies in a population with borderline sufficient iodine intake: Inluences of age and sex. Clin Chem. 2006;52:104-11.
12. Lim VS. Thyroid function in patients with chronic renal failure. Am J Kidney Dis. 2001;38(Suppl 1):S80-4.
13. Niloofar H, Sayed M, Behnam N.Examine of thyroid function in pediatric nrphrotic syndrome. Intern J Pediatr. 2015;3(2):59-65.
14. Lo JC, Chertow GM, Go AS, Hsu CY. Increased prevalence of subclinical and clinical hypothyroidism in persons with chronic kidney disease. Kidney Int. 2005;67:1047-52.
15. Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A More Accurate Method To Estimate Glomerular Filtration Rate from Serum Creatinine: A New Prediction Equation. Ann InternMed. 1999;130(6):461-70.