Database analysis of hypersensitivity pneumonitis in Japan

Shohei Yamashita; Tsukasa Okamoto; Tatsuo Kawahara; Tomoya Tateishi; Tatsuhiko Anzai; Kunihiko Takahashi; Kiyohide Fushimi; Yasunari Miyazaki

doi:10.1016/j.resinv.2022.12.003

Database analysis of hypersensitivity pneumonitis in Japan

Respir Investig. 2023 Mar;61(2):172-180. doi: 10.1016/j.resinv.2022.12.003. Epub 2023 Jan 23.

Authors

Shohei Yamashita¹, Tsukasa Okamoto², Tatsuo Kawahara¹, Tomoya Tateishi¹, Tatsuhiko Anzai³, Kunihiko Takahashi³, Kiyohide Fushimi⁴, Yasunari Miyazaki⁵

Affiliations

¹ Department of Respiratory Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
² Department of Respiratory Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan; Department of Pulmonary Immunotherapeutics, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
³ M&D Data Science Center, Tokyo Medical and Dental University, 2-3-10, Kandasurugadai, Chiyoda-ku, Tokyo, 101-0062, Japan.
⁴ Department of Health Policy and Informatics, Tokyo Medical and Dental University Graduate School of Medicine, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
⁵ Department of Respiratory Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan. Electronic address: miyazaki.pilm@tmd.ac.jp.

PMID: 36696702
DOI: 10.1016/j.resinv.2022.12.003

Abstract

Background: Three epidemiological small-scale studies on hypersensitivity pneumonitis (HP) have been performed in Japan to date. Herein, we aimed to clarify the clinical characteristics of various types of HP diseases using a large nationwide database in Japan.

Methods: We used the Japanese Diagnostic Procedure Combination database that includes data from 1,031 participant hospitals. Patients with HP from 2011 to 2017 were identified using International Classification of Diseases 10th Revision codes. We analyzed patient characteristics, the yearly transition of the number of HP cases, rate per one million hospitalizations, geographical distribution, seasonality, and risk factors for in-hospital mortality.

Results: In total, 3,634 patients with HP were identified, including summer-type HP (SHP) (n = 490), bird fancier's lung (BFL) (n = 199), ventilation pneumonitis (n = 106), farmer's lung (n = 48), and unspecified HP (n = 2761). The length of hospital stay was significantly longer in patients with BFL (19 days) than in patients with SHP (15 days). SHP was more prevalent in the southwestern region of Japan, and hospitalization occurred mainly in summer (37.8%) and fall (37.3%). Ventilation pneumonitis was predominant in winter (28.6%) and spring (38.7%). In-hospital mortality was significantly associated with old age (p < 0.001), low body mass index (p = 0.016), severe dyspnea (p < 0.001), and BFL diagnosis on admission (p = 0.031).

Conclusions: This study revealed the clinical characteristics of SHP and BFL, including the frequency of causative antigens, geographical distribution, seasonality, and risk factors for mortality, which may help in diagnosing HP and identifying causative antigens.

Keywords: Bird fancier's lung; Epidemiological study; Hypersensitivity pneumonitis; Nationwide database; Summer-type hypersensitivity pneumonitis.

MeSH terms

Alveolitis, Extrinsic Allergic* / diagnosis
Bird Fancier's Lung* / diagnosis
Humans
Japan
Methylcellulose
Pneumonia*

Substances

Methylcellulose