title: Clinical characteristics of asthma combined with COPD feature.
abstract: OBJECTIVE
  In clinical practice, some patients with asthma show incompletely reversible airflow obstruction, resembling chronic obstructive pulmonary disease (COPD). The aim of this study was to analyze this overlap phenotype of asthma with COPD feature.
  
  
  METHODS
  A total of 256 patients, over the age of 40 years or more with a diagnosis of asthma, based on either 1) positive response to bronchodilator: >200 mL forced expiratory volume in 1 s (FEV₁) and >12% baseline or 2) positive methacholine or mannitol provocation test, were enrolled. Among the asthma patients, we defined the overlap group with incompletely reversible airflow obstruction [postbronchodilator FEV₁/forced vital capacity (FVC)<70] at the initial time of admission and continuing airflow obstruction after at least 3 months follow up. We evaluated clinical features, serum eosinophil counts, serum total immunoglobulin (Ig) E with allergy skin prick test, spirometry, methacholine or mannitol provocation challenges and bronchodilator responses, based on their retrospective medical record data. All of the tests mentioned above were performed within one week.
  
  
  RESULTS
  The study population was divided into two groups: asthma only (62%, n=159, postbronchodilator FEV₁/FVC≥70) and overlap group (38%, n=97, postbronchodilator FEV₁/FVC<70). The overlap group was older, and contained more males and a higher percentage of current or ex-smokers than the asthma only group. Significantly lower FEV₁ and higher total lung capacity, functional residual capacity, and residual volume were observed in the overlap group. Finally, significantly lower serum eosinophil count and higher IgE were seen in the overlap group.
  
  
  CONCLUSIONS
  Our results showed that the overlap phenotype was older, male asthmatic patients who have a higher lifetime smoking intensity, more atopy and generally worse lung function.
authors: Division of Allergy and Pulmonary Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Hea Yon
authors: HY
authors: Lee
authors: Division of Allergy and Pulmonary Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Ji Young
authors: JY
authors: Kang
authors: Division of Allergy and Pulmonary Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Hyoung Kyu
authors: HK
authors: Yoon
authors: Division of Allergy and Pulmonary Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Sook Young
authors: SY
authors: Lee
authors: Division of Allergy and Pulmonary Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Soon Suk
authors: SS
authors: Kwon
authors: Division of Allergy and Pulmonary Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Young Kyoon
authors: YK
authors: Kim
authors: Division of Allergy and Pulmonary Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea. chinkook@catholic.ac.kr.
authors: Chin Kook
authors: CK
authors: Rhee
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001249:Asthma / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000503:physiopathology*; D012189:Retrospective Studies; D012737:Sex Factors
keywords: Asthma; airway hyperresponsiveness; chronic obstructive pulmonary disease; overlap