Retrospective Cohort Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Dec 26, 2021; 9(36): 11173-11182
Published online Dec 26, 2021. doi: 10.12998/wjcc.v9.i36.11173
Analysis of the incidence and influencing factors of hyponatremia before 131I treatment of differentiated thyroid carcinoma
Jing-Jia Cao, Can-Hua Yun, Juan Xiao, Yong Liu, Wei Wei, Wei Zhang
Jing-Jia Cao, Can-Hua Yun, Juan Xiao, Yong Liu, Wei Wei, Wei Zhang, Department of Nuclear Medicine, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250033, Shandong Province, China
Author contributions: Cao JJ, Yun CH, Xiao J, Liu Y and Wei W contributed acquisition of data; Cao JJ, Yun CH and Xiao J contributed analysis of data, drafting the article; Zhang W conceived and designed the study; all authors have read and approved the final manuscript.
Institutional review board statement: The study was approved by the Institutional Review Board of the Second Hospital, Cheeloo College of Medicine, Shandong University (KYLL-2018[LW]013). All procedures complied with the Declaration of Helsinki for research involving human subjects.
Informed consent statement: Written informed consent was obtained from each patient.
Conflict-of-interest statement: All authors have no conflict of interest related to the manuscript.
Data sharing statement: The original anonymous dataset is available on request from the corresponding author.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Wei Zhang, MD, Professor, Department of Nuclear Medicine, The Second Hospital, Cheeloo College of Medicine, Shandong University, No. 247 Road, Tianqiao District, Jinan 250033, Shandong Province, China. sdeyzhangwei@126.com
Received: May 11, 2021
Peer-review started: May 11, 2021
First decision: July 8, 2021
Revised: August 3, 2021
Accepted: November 15, 2021
Article in press: November 15, 2021
Published online: December 26, 2021
Abstract
BACKGROUND

Hyponatremia is a common clinical electrolyte disorder. However, the association between hyponatremia and acute hypothyroidism is unclear. Acute hypothyroidism is usually seen in patients who undergo preparation for radioactive iodine therapy.

AIM

To analyze the incidence and influencing factors of hyponatremia in a condition of iatrogenic acute hypothyroidism in patients with differentiated thyroid cancer (DTC) before 131I treatment.

METHODS

The study group consisted of 903 DTC patients who received 131I treatment. The clinical data before and after surgery, as well as on the day of 131I treatment were analyzed. According to the blood sodium level before 131I treatment, patients were divided into the non-hyponatremia group and hyponatremia group. Correlations between serum sodium levels before 131I treatment and baseline data were analyzed. Univariate analysis and binary logistic regression were performed to identify the influencing factors of hyponatremia.

RESULTS

A total of 903 patients with DTC, including 283 (31.3%) males and 620 (68.7%) females, with an average age of 43.8 ± 12.7 years, were included in this study. The serum sodium levels before surgery and 131I treatment were 141.3 ± 2.3 and 140.5 ± 2.1 mmol/L, respectively (P = 0.001). However, the serum sodium levels in males and females before 131I treatment were lower than those before surgery. Patients aged more than 60 years and less than 60 years also showed decreased serum sodium levels before 131I treatment. In addition, the estimated glomerular filtration rate (eGFR) in males and females decreased before 131I treatment compared with those before surgery (P = 0.001). Moreover, eGFR in patients over 60 years and under 60 years decreased before 131I treatment, when compared with that before surgery. There were no significant differences in serum potassium, calcium, albumin, hemoglobin, and blood glucose in patients before surgery and 131I treatment (P > 0.05). Among the 903 patients, 23 (2.5%) were diagnosed with hyponatremia before 131I treatment, including 21 cases (91.3%) of mild hyponatremia and 2 cases (8.7%) of moderate hyponatremia. Clinical data showed that patients with mild hyponatremia had no specific clinical manifestations, while moderate hyponatremia cases were mainly characterized by fatigue and dizziness, which were similar to neurological symptoms caused by hypothyroidism and were difficult to distinguish. Correlation analysis showed a correlation between serum sodium before 131I treatment and the preoperative level (r = 0.395, P = 0.001). There was no significant correlation between blood sodium and thyroid-stimulating hormone (TSH) levels and urine iodine before 131I treatment (r = 0.045, P = 0.174; r = 0.013, P = 0.697). Univariate analysis showed that there were significant differences in age, sex, history of diuretic use, distant metastasis, preoperative blood sodium, blood urea nitrogen (BUN), eGFR, TSH and urinary iodine between the two groups (all P < 0.05). Logistic regression analysis showed that factors such as history of diuretic use, distant metastases, preoperative sodium and BUN were all influencing factors of hyponatremia. The Hosmer and Lemeshow test (c2 = 2.841, P = 0.944) suggested a high fit of the model. Omnibus tests of model coefficients indicated the overall significance of the model in this fitted model (P < 0.05). Preoperative serum sodium was a significant factor associated with pre-131I therapy hyponatremia (OR = 0.763; 95%CI: 0.627-0.928; P = 0.007).

CONCLUSION

The incidence of hyponatremia induced by 131I treatment preparation was not high. Preparation for radioactive iodine therapy was not a risk factor for the development of hyponatremia in thyroid cancer patients.

Keywords: Differentiated thyroid cancer, Hyponatremia, Incidence, Low iodine diet, Logistic regression analysis

Core Tip: We analyzed the incidence and influencing factors of hyponatremia in patients with differentiated thyroid cancer (DTC) before 131I treatment. We evaluated 903 postoperative DTC patients who received 131I treatment. The results suggest that the incidence of hyponatremia induced by 131I treatment preparation was not high. The identified influencing factors of hyponatremia included history of diuretic use, distant metastases, preoperative sodium and blood urea nitrogen. Our findings may help to improve patient management during the preparation period for 131I treatment.