Clinical significance of thyroid hormone and antibodies in patients with idiopathic interstitial pneumonia

Yuki Sato; Yoshinori Tanino; Takefumi Nikaido; Ryuichi Togawa; Takaya Kawamata; Xintao Wang; Naoko Fukuhara; Hikaru Tomita; Mikako Saito; Natsumi Watanabe; Mami Rikimaru; Takashi Umeda; Julia Morimoto; Tatsuhiko Koizumi; Yasuhito Suzuki; Kenichiro Hirai; Manabu Uematsu; Hiroyuki Minemura; Atsuro Fukuhara; Suguru Sato; Junpei Saito; Kenya Kanazawa; Yoko Shibata

doi:10.21037/jtd.2020.01.02

Clinical significance of thyroid hormone and antibodies in patients with idiopathic interstitial pneumonia

J Thorac Dis. 2020 Mar;12(3):522-537. doi: 10.21037/jtd.2020.01.02.

Authors

Yuki Sato¹, Yoshinori Tanino¹, Takefumi Nikaido¹, Ryuichi Togawa¹, Takaya Kawamata¹, Xintao Wang¹, Naoko Fukuhara¹, Hikaru Tomita¹, Mikako Saito¹, Natsumi Watanabe¹, Mami Rikimaru¹, Takashi Umeda¹, Julia Morimoto¹, Tatsuhiko Koizumi¹, Yasuhito Suzuki¹, Kenichiro Hirai¹, Manabu Uematsu¹, Hiroyuki Minemura¹, Atsuro Fukuhara¹, Suguru Sato¹, Junpei Saito¹, Kenya Kanazawa¹, Yoko Shibata¹

Affiliation

¹ Department of Pulmonary Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan.

Abstract

Background: Hypothyroidism was recently reported to be common and to predict mortality in patients with idiopathic pulmonary fibrosis (IPF). In addition, a high prevalence of hypothyroidism was shown in patients with idiopathic pleuroparenchymal fibroelastosis. However, in idiopathic interstitial pneumonia (IIP), a clinical significance of thyroid function has not been clarified in detail. The goal of this study was to investigate the clinical significance of thyroid function and the presence of thyroid antibodies in IIP.

Methods: We have reviewed IIP patients, and analyzed the positivity of thyroid antibodies at first. Next, the relationship of clinical characteristics with thyroid function and the positivity of thyroid antibodies was analyzed. Lastly, the positivity of thyroid antibodies and other autoantibodies was evaluated.

Results: In IIP patients, thyroglobulin and thyroid peroxidase antibodies were positive in 17 and 16%, respectively, and 22% of patients had either or both antibodies. Subclinical and/or overt hypothyroidism was confirmed in 7% of IIP patients. The free thyrotropin level had a significant positive correlation with vital capacity and a significant negative correlation with the C-reactive protein and surfactant protein-A levels, and erythrocyte sedimentation ratio (ESR). In addition, autoantibodies suggestive of connective tissue diseases (CTDs) were positive in more than two thirds of IIP patients with the thyroid antibody, and the positive rate of antinuclear and proteinase-3 anti-neutrophil cytoplasmic antibodies was significantly higher in IIP patients with thyroid antibodies than those without the antibodies.

Conclusions: Although thyroid dysfunction is not frequent, thyroid hormones and thyroid antibodies are possibly involved in the pathogenesis of IIP and their evaluation may be clinically useful to identify the clinical phenotype of IIP with autoimmune features.

Keywords: Thyroid hormone; autoimmune features; clinical phenotype; interstitial pneumonia; thyroid antibodies.