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Exacerbations in non-COPD patients: truth or myth—authors’ response
  1. Wan C Tan1,
  2. Jean Bourbeau2,
  3. Shawn Aaron3,
  4. J Mark FitzGerald4,
  5. Paul Hernandez5,
  6. Robert Cowie6,
  7. Kenneth R Chapman7,
  8. Darcy Marciniuk8,
  9. Francois Maltais9,
  10. Sonia Buist10,
  11. Denis O'Donnell11,
  12. Don D Sin1
  13. for the CanCOLD Collaborative Research Group
  1. 1 UBC James Hogg Research Center, University of British Columbia Vancouver, British Columbia, Canada
  2. 2 McGill University, Respiratory, Montreal Chest Institute, Montréal, Quebec, Canada
  3. 3 Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
  4. 4 Department of Respiratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
  5. 5 Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
  6. 6 Departments of Medicine and Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
  7. 7 Department of Respiratory Medicine, University of Toronto, Toronto, Ontario, Canada
  8. 8 Division of Respirology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
  9. 9 Centre de Pneumologie de l'hôpital Laval, Quebec City, Québec, Canada
  10. 10 Oregon Health and Science University, Portland, Oregon, USA
  11. 11 Division of Respiratory & Critical Care Medicine, Queen's University, Kingston, Ontario, Canada
  1. Correspondence to Dr Wan C Tan, UBC James Hogg Research Centre, Providence Heart + Lung Institute, University of British Columbia, St Paul's Hospital, Rm 166, 1081 Burrard Street, Vancouver, British Columbia, Canada V6Z 1Y6; wan.tan{at}

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Dear Sir,

We are grateful to Dr Khurana and Dr Aggarwal for their interest1 in our paper.2

On their first point, we agree that we should be careful about terminology. We evaluated a random sample of individuals representative of the general population rather than patients, so the findings that episodes of respiratory events occurred in these subjects would likely reflect real events in the general population. Furthermore, our study definition for exacerbations was the same standard questionnaire criteria for exacerbations used in clinical trials of selected patients with COPD.3

On the second point on aetiologies for non-COPD subgroup in this study, we would like to emphasise that ‘non-COPD’ was defined by the absence of chronic airflow limitation using the standard, although arbitrary spirometric criteria. We excluded those individuals with self-reported chronic obstructive lung diseases, …

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  • PostScript
    Deepak Aggarwal Alkesh Kumar Khurana
  • Respiratory epidemiology
    W C Tan J Bourbeau P Hernandez K R Chapman R Cowie J M FitzGerald D D Marciniuk F Maltais A S Buist D E O'Donnell D D Sin S D Aaron for the CanCOLD Collaborative Research Group Jonathon Samet Milo Puhan Qutayba Hamid James C Hogg Jean Bourbeau Wan C Tan Carole Jabet Maria Sedona Palmina Mancino Yvan Fortier Don Sin Yuexin Li Sheena Tam Joe Comeau Adrian Ng Harvey Coxson Tara Candido Jonathon Leipsic Cameron Hague Jeremy Road Andrea Benedetti Carlo Mara Mohsen Savafi Andrea Gershon Teresa To Wan C Tan Harvey Coxson Jean Bourbeau Zhi L Pei Denis Jensen Denis O’Donnell Wan C Tan Christine Lo Jeong Min Carly Moy Anna La Lau Ashleigh Sran Ebony Swanson Ying Yuan Daniel Chen Lu Zheng Tina Yang Junior Chuang Best Guo Licong Li Kendall Chan Rahmath Khanam Daria Maslennikova Sarah Cheng Catherine Peng Bryan Chiang Sarah Guo Kyrsten Payne Jean Bourbeau Palmina Mancino Maria Sedona Carmen Darauay Myriam Costa Kenneth Chapman Patricia McClean Heather Sporn Robert Cowie Ann Cowie Curtis Dumonceaux Jessica Moore Paul Hernandez Scott Fulton Maria Yorke Natalie Fiorotos Ashley Rowe Shawn Aaron Kathy Vandemheen Gay Pratt Jeevitha Srighanthan Denis O’Donnell Kathy Webb Naparat Amornputtisathaporn Kate Cheung Kate Whelan Jenny Cheng Francois Maltais Joanie Couture Luciana Garcia Pereira Marie-Josée Breton Cynthia Brouillard Darcy Marciniuk Ron Clemens Janet Baran