title: Clinical Utility of Additional Measurement of Total Lung Capacity in Diagnosing Obstructive Lung Disease in Subjects With Restrictive Pattern of Spirometry.
abstract: BACKGROUND
  Total lung capacity (TLC), forced expiratory flow between 25 and 75% (FEF25-75%), peak expiratory flow (PEF), or post-bronchodilator volume response is recommended to detect obstructive abnormalities in the lung. The present study was performed to evaluate the usefulness of these pulmonary function test (PFT) parameters to diagnose obstructive lung disease in subjects with a restrictive pattern of spirometry.
  
  
  METHODS
  A retrospective study was conducted in 64 subjects with a restrictive pattern of spirometry (normal FEV1/FVC and low FVC) out of 3,030 patients who underwent all pre- and post-bronchodilator spirometry and lung volume measurement between April 2008 and December 2010. After subjects were clinically classified into those with obstructive lung disease, restrictive lung disease, and mixed lung disease, the agreements between the clinical diagnosis and PFT classification according to TLC, FEF(25-75%), PEF, and post-bronchodilator response criteria were compared.
  
  
  RESULTS
  Of 64 subjects, 18 (28.1%) were classified with obstructive lung disease, 39 (60.9%) had restrictive lung disease, 1 (1.6%) had mixed lung disease, and 6 (9.4%) had no clinical lung disease. Among the 58 subjects with clinical lung disease, 22 (37.9%), 37 (63.8%), 33 (56.9%), and 3 (5.2%) were classified as having obstructive pattern based on TLC, FEF25-75%, PEF, and post-bronchodilator response criteria, respectively. The kappa coefficients for the agreement between the clinical classification and PFT classification using TLC, FEF25-75%, PEF, and post-bronchodilator response criteria in 58 subjects were 0.59, 0.18, 0.17, and < 0.01, respectively.
  
  
  CONCLUSIONS
  The additional measurement of TLC is more useful than FEF25-75%, PEF, and post-bronchodilator response for diagnosis of obstructive lung disease in subjects with a restrictive pattern of spirometry, when obstructive lung disease is clinically suspected.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Lee
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Kyung Hee University Hospital at Gangdong, School of Medicine, Kyung Hee University, Seoul, Korea.
authors.forename: Boksoon
authors.initials: B
authors.lastname: Chang
authors.affiliation: Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul, Korea.
authors.forename: Kyunga
authors.initials: K
authors.lastname: Kim
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Won Jun
authors.initials: WJ
authors.lastname: Song
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hae Ri
authors.initials: HR
authors.lastname: Chon
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hyung Koo
authors.initials: HK
authors.lastname: Kang
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jung Soo
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Byeong-Ho
authors.initials: BH
authors.lastname: Jeong
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Yeon-Mok
authors.initials: YM
authors.lastname: Oh
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. hyeyunpark@skku.edu.
authors.forename: Hye Yun
authors.initials: HY
authors.lastname: Park
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008171:Lung Diseases / Q000175:diagnosis* / Q000503:physiopathology; D008173:Lung Diseases, Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D013147:Spirometry / Q000379:methods / Q000706:statistics & numerical data*; D014109:Total Lung Capacity
keywords: airway obstruction; maximal midexpiratory flow; obstructive lung diseases; peak expiratory flow; spirometry; total lung capacity