Research Article

Association between Hypothyroidism and Proteinuria in Japanese Patients with Chronic Kidney Disease: A New Concept of Nephrogenic Hypothyroidism

Rene Yuasa1,2*, Masaki Muramatsu1, Akinobu Saitou1, Yuji Osuka3, Toshisuke Morita3, Yuko Hamasaki1, Ken Sakai1

1Department of Nephrology, Toho University School of Medicine, Tokyo, Japan

2Department of Clinical Medicine, Toho University School of Nursing, Tokyo, Japan

3Division of Clinical Examination, Toho University Omori Medical Center, Tokyo, Japan

4Dean of School of Medicine, Toho University, Tokyo, Japan

*Corresponding author: Rene Yuasa, Department of Nephrology, Toho University School of Medicine, Tokyo, Japan

Received Date: 09 June 2023

Accepted Date: 15 June 2023

Published Date: 19 June 2023

Citation: Yuasa R, Muramatsu M, Saitou A, Osuka Y, Morita T, Hamasaki Y, et al. (2023) Association between Hypothyroidism and Proteinuria in Japanese Patients with Chronic Kidney Disease: A New Concept of Nephrogenic Hypothyroidism. J Urol Ren Dis 08: 1336. https://doi.org/10.29011/2575-7903.001336

Abstract

Purpose: Patients with Chronic Kidney Disease (CKD) complicated by hypothyroidism exhibit a higher prevalence of Urine Protein (UP) than that in the general population. This study was aimed at investigating thyroid hormones and thyroid hormone-binding proteins excreted in urine to elucidate the UP-associated underlying mechanisms of hypothyroidism.

Methods: Between November 2016 and August 2018, thyroid function (serum free T3 [sFT3], free T4 [sFT4], and Thyroid-Stimulating Hormone [sTSH]), kidney function (Estimated Glomerular Filtration Rate [eGFR]), and albumin (Alb) were evaluated in 99 patients. A urine examination was also performed to assess the following parameters: total T3, total T4, TSH, Alb, preAlb, thyroid-binding globulin, and protein.

Results: The median patient age at study recruitment was 60 years; 50 patients (49.5%) were male. The median eGFR and Alb level were 20.3 ml/min/1.73 m2 and 3.8 g/dL, respectively. Twenty-one (20.8%) of the 101 patients were diagnosed with Nephrotic Syndrome (NS). The median sFT3, sFT4, and sTSH levels were within normal limits. Approximately 70% of the patients had thyroid dysfunction and 41.6% had overt hypothyroidism and subclinical hypothyroidism. Regarding the characteristics of NS and non-NS (NNS) patients, age and Alb level were significantly different between these groups, while intergroup differences in sex and eGFR were not significant. We found that urinary T4 and TSH levels were higher in the NS group; thus, hypothyroidism was severer.

Conclusion: We found a significant association between hypothyroidism and NS regardless of sex. Urinary loss of thyroid hormones might be a factor influencing hypothyroidism independent of autoimmunity.

Keywords: Chronic kidney disease; Hypothyroidism; Nephrogenic hypothyroidism; Proteinuria

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Journal of Urology and Renal Diseases