title: Systemic Inflammation in Older Adults With Asthma-COPD Overlap Syndrome.
abstract: OBJECTIVE
  The role of systemic inflammation on asthma-COPD overlap syndrome is unknown. This study aimed to examine systemic inflammation in asthma-COPD overlap syndrome, and to identify associations between clinical characteristics and inflammatory mediators in asthma-COPD overlap syndrome.
  
  
  METHODS
  In 108 adults older than 55 years comprising healthy controls (n=29), asthma (n=16), COPD (n=21) and asthma-COPD overlap syndrome (n=42), serum high sensitivity C-reactive protein and Interleukin 6 (IL-6) were assayed. Spirometry, induced sputum, quality of life, comorbidities and medications were assessed, and their associations with asthma-COPD overlap syndrome were analyzed using logistic regression. Associations between systemic inflammatory mediators and clinical characteristics were tested in multivariate linear regression models.
  
  
  RESULTS
  Patients with asthma-COPD overlap syndrome had significantly elevated IL-6 levels compared with healthy controls and asthmatics. Age, comorbidity index and IL-6 level were independently associated with asthma-COPD overlap syndrome. FEV1% predicted was inversely associated with IL-6 level, and cardiovascular disease was associated with an increased IL-6 level. Systemic markers were not associated with airway inflammation.
  
  
  CONCLUSIONS
  Systemic inflammation is commonly present in asthma-COPD overlap syndrome, and asthma-COPD overlap syndrome resembled COPD in terms of systemic inflammation. IL-6 is a pivotal inflammatory mediator that may be involved in airflow obstruction and cardiovascular disease and may be an independent treatment target.
authors.affiliation: Respiratory Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China. ; Priority Research Centre for Asthma and Respiratory Diseases, University of Newcastle; Hunter Medical Research Institute, Newcastle, NSW, Australia. ; Department of Respiratory and Sleep Medicine, John Hunter Hospital, New Lambton, NSW, Australia.
authors.forename: Juan-Juan
authors.initials: JJ
authors.lastname: Fu
authors.affiliation: Priority Research Centre for Asthma and Respiratory Diseases, University of Newcastle; Hunter Medical Research Institute, Newcastle, NSW, Australia. ; School of Nursing and Midwifery, Faculty of Health, University of Newcastle, NSW, Australia. ; Department of Respiratory and Sleep Medicine, John Hunter Hospital, New Lambton, NSW, Australia.
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: McDonald
authors.affiliation: Priority Research Centre for Asthma and Respiratory Diseases, University of Newcastle; Hunter Medical Research Institute, Newcastle, NSW, Australia. ; Department of Respiratory and Sleep Medicine, John Hunter Hospital, New Lambton, NSW, Australia. ; Woolcock Institute of Medical Research, Sydney NSW, Australia.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gibson
authors.affiliation: Priority Research Centre for Asthma and Respiratory Diseases, University of Newcastle; Hunter Medical Research Institute, Newcastle, NSW, Australia. ; Department of Respiratory and Sleep Medicine, John Hunter Hospital, New Lambton, NSW, Australia.
authors.forename: Jodie L
authors.initials: JL
authors.lastname: Simpson
keywords: Ageing; C-reactive protein; asthma; comorbidity; interleukin-6; obstructive airway disease