title: Characteristics of phenotypes of elderly patients with asthma.
abstract: BACKGROUND
  The characteristics of phenotypes of elderly patients with asthma are unknown. The aim of this study was to classify these phenotypes using lung function tests and images from high-resolution computed tomography (HRCT), and to identify associations between clinical characteristics and phenotypes.
  
  
  METHODS
  A cross-sectional study was conducted in 165 elderly patients (>65 years of age) who underwent a multidimensional assessment of clinical and functional status and comorbidity. The patients were divided into three phenotypes: (1) asthma-predominant, (2) asthma-obstructive airway disease (OAD) overlap without emphysema, and (3) asthma-OAD overlap with emphysema (asthma-emphysema overlap) based on chest HRCT. A receiver operating characteristic (ROC) curve was constructed to evaluate the cutoff for differentiating between the two OAD phenotypes. Multivariate analysis was also used to distinguish between these two phenotypes.
  
  
  RESULTS
  The phenotypes were asthma-predominant in 48 patients (29%), asthma-OAD without emphysema in 36 (22%), and asthma-emphysema in 81 (49%). Patients with asthma-emphysema were more frequent smokers. In multivariate analysis, smoking status (odds ratio 2.92: 95% CI 1.21-7.00, P = 0.03) and % predicted FEV1 ≤70% (odds ratio 3.18: 95% CI 1.13-8.92, P = 0.03) differed significantly between the asthma-emphysema and asthma-OAD without emphysema phenotypes.
  
  
  CONCLUSIONS
  Half of elderly patients with asthma are characterized by asthma-emphysema overlap. Our results showed that elderly patients with asthma who are smokers and have moderate or severe OAD are also likely to have emphysema.
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University Faculty of Medicine, Osaka, Japan. Electronic address: hsano@med.kindai.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sano
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University Faculty of Medicine, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Iwanaga
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University Faculty of Medicine, Osaka, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishiyama
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University Faculty of Medicine, Osaka, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Sano
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University Faculty of Medicine, Osaka, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Higashimoto
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University Faculty of Medicine, Osaka, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Tomita
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University Faculty of Medicine, Osaka, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tohda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D001772:Blood Cell Count; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D045853:Exhalation; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D009569:Nitric Oxide; D010641:Phenotype; D011656:Pulmonary Emphysema / Q000175:diagnosis; D012372:ROC Curve; D012129:Respiratory Function Tests; D012307:Risk Factors; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed
chemical_list: D018927:Anti-Asthmatic Agents; D009569:Nitric Oxide; D007073:Immunoglobulin E
keywords: ACOS; Elderly asthma; Emphysema; HRCT; Phenotype