title: Clinical, physiological, and radiological features of asthma-chronic obstructive pulmonary disease overlap syndrome.
abstract: BACKGROUND
  Asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) is associated with rapid decline in lung function, poorer health-related quality-of-life outcomes, and frequent exacerbations, compared to COPD alone. Although the numbers of patients with ACOS have increased, there is little established evidence regarding diagnostic criteria and treatment options. Thus, the aim of our study was to clarify the clinical, physiological, and radiological features of patients with ACOS.
  
  
  METHODS
  We examined a total of 100 patients with COPD and 40 patients with ACOS, who were selected based on clinical criteria. All patients underwent baseline testing, including a COPD assessment test, pulmonary function tests, and multidetector row computed tomography imaging. Percentage of low attenuation volume, percentage of wall area, and percentage of total cross-sectional area of pulmonary vessels less than 5 mm(2) (%CSA <5) were determined using multidetector row computed tomography. ACOS patients were administered a fixed dose of budesonide/formoterol (160/4.5 μg, two inhalations; twice daily) for 12 weeks, after which the ACOS patients underwent multidetector row computed tomography to measure the same parameters.
  
  
  RESULTS
  At baseline, the ACOS patients and COPD patients had a similar degree of airflow limitation, vital capacity, and residual volume. ACOS patients had higher COPD assessment test scores, percentage of wall area, and %CSA <5 than COPD patients. Compared to baseline, budesonide/formoterol treatment significantly increased the forced expiratory volume in 1 second and decreased the degree of airway wall thickness (percentage of wall area) as well as pulmonary microvascular density (%CSA <5) in ACOS patients.
  
  
  CONCLUSIONS
  Our results suggest that ACOS is characterized by an airway lesion-dominant phenotype, in contrast to COPD. Higher %CSA <5 might be a characteristic feature of ACOS.
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tada
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Kawata
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Matsuura
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ikari
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Kasahara
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tatsumi
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage; D001249:Asthma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000008:administration & dosage; D000069502:Budesonide, Formoterol Fumarate Drug Combination / Q000008:administration & dosage; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D010641:Phenotype; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology; D011667:Pulmonary Veins / Q000000981:diagnostic imaging; D020127:Recovery of Function; D012129:Respiratory Function Tests; D013577:Syndrome; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018927:Anti-Asthmatic Agents; D001993:Bronchodilator Agents; D000069502:Budesonide, Formoterol Fumarate Drug Combination
keywords: budesonide/formoterol; cross-sectional area (CSA); percentage of wall area (WA%); pulmonary vessels