title: Coexisting COPD in elderly asthma with fixed airflow limitation: Assessment by DLco %predicted and HRCT.
abstract: BACKGROUND
  Asthma patients with fixed airflow limitation (FL) are theoretically classified into two phenotypes, that is, coexisting chronic obstructive pulmonary disease (COPD) and asthmatic airway remodeling. However, the precise percentages of such patients are not known.
  
  
  OBJECTIVE
  To assess the prevalence of patients with both FL and COPD components in elderly asthma.
  
  
  METHODS
  We evaluated patients by lung diffusion impairment and emphysematous findings in high-resolution computed tomography (HRCT) as candidates for COPD components, as a multicenter, cross-sectional survey. Asthma outpatients ≥ 50 years of age were enrolled from Tohoku University Hospital, Sendai, Japan, and four hospitals (Tohoku Medical and Pharmaceutical University Wakabayashi Hospital, Sendai, JAPAN; Wakayama Medical University Hospital, Kimiidera, Japan; Hiraka General Hospital, Yokote, Japan; Iwate Prefectural Isawa Hospital, Oshu, Japan) with pulmonary physicians from March 1, 2013 to November 30, 2014.
  
  
  RESULTS
  The prevalence of patients with FEV1/FVC <70% was 31.0% of those in their 50s, 40.2% of those in their 60s and 61.9% of those in their 70s or older. The prevalence of those patients with lung diffusion impairment (i.e. the percent predicted values of diffusing capacity of the lung for carbon monoxide (DLco %predicted) <80%) or emphysematous findings in HRCT (i.e. the appearance of low attenuation area (LAA)) was 18.3% of those in their 50s, 13.8% of those in their 60s and 35.7% of those in their 70s or older.
  
  
  CONCLUSIONS
  Nearly half of the patients with FL in elderly asthma show coexisting COPD components when assessed by DLco %predicted and LAA in HRCT.
authors: a Department of Respiratory Medicine , Tohoku University Graduate School of Medicine , Sendai , Japan.
authors: Tsutomu
authors: http://orcid.org/0000-0003-0600-0610
authors: T
authors: Tamada
authors: a Department of Respiratory Medicine , Tohoku University Graduate School of Medicine , Sendai , Japan.
authors: Hisatoshi
authors: H
authors: Sugiura
authors: b Tohoku Medical and Pharmaceutical University Wakabayashi Hospital , Sendai , Japan.
authors: Tsuneyuki
authors: T
authors: Takahashi
authors: c Division of Respiratory Medicine and Infectious Disease, Graduate School of Medicine, Yamaguchi University , Ube , Japan.
authors: Kazuto
authors: K
authors: Matsunaga
authors: d Osaki Citizen Hospital , Osaki , Japan.
authors: Keiji
authors: K
authors: Kimura
authors: e Iwate Prefectural Isawa Hospital , Oshu , Japan.
authors: Uichiro
authors: U
authors: Katsumata
authors: f National Hospital Organization Tokyo National Hospital , Kiyose , Tokyo , Japan.
authors: Ken
authors: K
authors: Ohta
authors: a Department of Respiratory Medicine , Tohoku University Graduate School of Medicine , Sendai , Japan.
authors: Masakazu
authors: M
authors: Ichinose
mesh_terms: D000368:Aged; D056151:Airway Remodeling / Q000502:physiology; D001249:Asthma / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012129:Respiratory Function Tests; D012907:Smoking / Q000453:epidemiology; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: ACOS; COPD; LAA; diffusion impairment