title: Factors associated with positive inhalation provocation test results in subjects suspected of having chronic bird-related hypersensitivity pneumonitis.
abstract: BACKGROUND
  Chronic bird-related hypersensitivity pneumonitis (BRHP) is often misdiagnosed as other interstitial lung diseases. While the utility of the inhalation provocation test (IPT) has been reported, the test is not commonly performed. In this study, we aimed to identify significant clinical variables associated with positive inhalation provocation test results in subjects suspected of having chronic BRHP. This would help clinicians decide whether to perform IPT in patients suspected of having chronic BRHP in real-life practice.
  
  
  METHODS
  We retrospectively evaluated 107 patients who underwent the IPT for suspected chronic BRHP. We used the IPT as the gold standard diagnostic tool for chronic BRHP.
  
  
  RESULTS
  Specific antibodies against pigeon dropping extract were documented in 52% of the IPT-positive patients but also in 38% of the IPT-negative patients (p=0.172). By using the logistic regression model, three significant predictors of IPT results were identified as follows: (1) a history of raising birds (odds ratio [OR] 3.112), (2) exposure to birds from the surrounding environment (OR 7.321), (3) white blood cell count (×102/μl; OR 0.959).
  
  
  CONCLUSIONS
  This study demonstrates that current or past exposure to avian antigens is a positive predictor of positive IPT results in patients suspected of having chronic BRHP.
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical and Dental University, Japan. Electronic address: masupulm@tmd.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Masuo
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical and Dental University, Japan. Electronic address: miyazaki.pilm@tmd.ac.jp.
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Miyazaki
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical and Dental University, Japan. Electronic address: suhara.pulm@tmd.ac.jp.
authors.forename: Kozo
authors.initials: K
authors.lastname: Suhara
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical and Dental University, Japan. Electronic address: mishizuka.pulm@tmd.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ishizuka
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical and Dental University, Japan. Electronic address: tfujie.pulm@tmd.ac.jp.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Fujie
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical and Dental University, Japan. Electronic address: ninase.pulm@tmd.ac.jp.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Inase
mesh_terms: D000368:Aged; D000818:Animals; D000941:Antigens; D001716:Bird Fancier's Lung / Q000175:diagnosis* / Q000276:immunology; D001717:Birds / Q000276:immunology; D001985:Bronchial Provocation Tests / Q000379:methods*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D000941:Antigens
keywords: Bird; Chronic hypersensitivity pneumonitis; Inhalation provocation test; Interstitial lung disease