ORIGINAL RESEARCH article
Front. Endocrinol.
Sec. Thyroid Endocrinology
Incidence and Risk Factors of Tocilizumab-Induced Hypofibrinogenemia in Patients with Thyroid Eye Disease: A Single-Center Retrospective Study
Provisionally accepted
- 1Department of Pharmacy, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- 2Capital Medical University, Beijing, China
- 3Department of Endocrinology, Civil Aviation General Hospital, Beijing, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Background: Tocilizumab, an interleukin-6 receptor antagonist, is increasingly used in moderate-to-severe thyroid eye disease. However, its association with hypofibrinogenemia remains underexplored in this population. Methods: This single-center retrospective study included 194 TED patients treated with Tocilizumab at Beijing Tongren Hospital between March 2023 and May 2025. Patients were stratified into a positive group (fibrinogen < 1.5 g/L) and a negative group (fibrinogen ≥1.5 g/L) based on post-treatment fibrinogen levels. Demographic, clinical, and laboratory data were analyzed to identify risk factors using univariate and multivariate logistic regression. Results: Among 194 patients, 89 (45.88%) developed hypofibrinogenemia (fibrinogen < 1.5 g/L). The most significant fibrinogen decline occurred after the first Tocilizumab administration (median reduction: 0.88 g/L). Nadir levels were most common before the third (21.1%) or fifth administration (23.6%). Multivariate analysis identified lower baseline fibrinogen (OR = 0.37, P =0.001), higher body weight (OR = 1.05, P=0.001), and lower prothrombin time (OR = 0.45, P=0.008) as independent risk factors. Conclusion: Hypofibrinogenemia was observed at a higher incidence (45.88%) in thyroid eye disease patients treated with tocilizumab. It typically did not occur immediately after administration but This is a provisional file, not the final typeset article emerged early in the treatment course and persisted with repeated dosing. Baseline fibrinogen level, body weight, and prothrombin time (PT) activity were identified as significant predictors.
Keywords: Adverse Drug Reaction, Hypofibrinogenemia, Risk factors, Thyroid eye disease, tocilizumab
Received: 05 Jan 2026; Accepted: 06 Feb 2026.
Copyright: © 2026 Wang, Hu, Xu, Zhou, Wang, Song and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Jiawei Wang
Zhihui Song
Xinglong Wang
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.