About the Authors

Samatha Sonnappa

Affiliations Observational and Pragmatic Research Institute Pte Ltd, Singapore, Singapore, Department of Respiratory Paediatrics, Rainbow Children’s Hospital, Bengaluru, India

Richard Martin

Affiliation National Jewish Health and the University of Colorado Denver, Denver, Colorado, United States of America

Elliot Israel

Affiliation Pulmonary and Critical Care Division, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, United States of America

Dirkje Postma

Affiliation Department of Pulmonary Medicine and Tuberculosis, University of Groningen, University Medical Center Groningen, the Netherlands

Wim van Aalderen

Affiliation Department of Pediatric Respiratory Diseases, Emma Children’s Hospital AMC, Amsterdam, the Netherlands

Annie Burden

Affiliation Observational and Pragmatic Research Institute Pte Ltd, Singapore, Singapore

Omar S. Usmani

Contributed equally to this work with: Omar S. Usmani, David B. Price

Affiliation National Heart and Lung Institute, Imperial College London & Royal Brompton Hospital, London, United Kingdom

David B. Price

Contributed equally to this work with: Omar S. Usmani, David B. Price

dprice@opri.sg

Affiliations Observational and Pragmatic Research Institute Pte Ltd, Singapore, Singapore, Academic Primary Care, Division of Applied Health Sciences, University of Aberdeen, Aberdeen, United Kingdom

on behalf of the Respiratory Effectiveness Group, Small Airways Study Group

The complete membership of the author group can be found in the Acknowledgments.

Competing Interests

Samatha Sonnappa is an employee of Observational and Pragmatic Research Institute Pte Ltd, which conducted this study and has conducted paid research in respiratory disease on behalf of the following other organizations in the past 5 years: Aerocrine, AKL Research and Development Ltd, AstraZeneca, Boehringer Ingelheim, British Lung Foundation, Chiesi, Meda, Mundipharma, Napp, Novartis, Pfizer, Respiratory Effectiveness Group, Takeda, Teva Pharmaceuticals, Theravance, UK National Health Service, Zentiva. Richard J. Martin reports grants from MedImmune, NHLBI, and Chiesi Farmaceutici SpA; consultancy fees from Teva Pharmaceuticals and PMD Healthcare; support for travel to meetings from Respiratory Effectiveness Group; royalties from UpToDate; and sits on an advisory board for AstraZeneca. In the past 36 months, Elliot Israel reports receiving consulting fees from AstraZeneca, Bird Rock Bio, Novartis, Nuvelution Pharmaceuticals, Philips Respironics, Regeneron Pharmaceuticals, TEVA Specialty Pharmaceuticals and Vitaeris, Inc; travel grant support from Research in Real Life (RiRL) and TEVA Specialty Pharmaceuticals; Deputy Editor fees from the American Thoracic Society, and having grant support paid to his institution from Genentech, Sanofi, and the NIH. The University of Groningen has received money for Dirkje Postma regarding a grant for research from Astra Zeneca, Chiesi, Genentec, GSK and Roche. Fees for consultancies were given to the University of Groningen by Astra Zeneca, Boehringer Ingelheim, Chiesi, GSK, Takeda and TEVA. Wim van Aalderen is a member of the Medical advisory board of Astra Zeneca. Anne Burden was an employee of Observational and Pragmatic Research Institute Pte Ltd at the time of the study. Observational and Pragmatic Research Institute Pte Ltd conducted this study and has conducted paid research in respiratory disease on behalf of the following other organizations in the past 5 years: Aerocrine, AKL Research and Development Ltd, AstraZeneca, Boehringer Ingelheim, British Lung Foundation, Chiesi, Meda, Mundipharma, Napp, Novartis, Pfizer, Respiratory Effectiveness Group, Takeda, Teva Pharmaceuticals, Theravance, UK National Health Service, Zentiva. David B. Price has board membership with Aerocrine, Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, Meda, Mundipharma, Napp, Novartis, and Teva Pharmaceuticals; consultancy agreements with Almirall, Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Meda, Mundipharma, Napp, Novartis, Pfizer, Teva Pharmaceuticals, and Theravance; grants and unrestricted funding for investigator-initiated studies (conducted through Observational and Pragmatic Research Institute Pte Ltd) from Aerocrine, AKL Research and Development Ltd, AstraZeneca, Boehringer Ingelheim, British Lung Foundation, Chiesi, Meda, Mundipharma, Napp, Novartis, Pfizer, Respiratory Effectiveness Group, Takeda, Teva Pharmaceuticals, Theravance, UK National Health Service, Zentiva; payment for lectures/speaking engagements from Almirall, AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, GlaxoSmithKline, Kyorin, Meda, Merck, Mundipharma, Novartis, Pfizer, Skyepharma, Takeda, and Teva Pharmaceuticals; payment for manuscript preparation from Mundipharma and Teva Pharmaceuticals; payment for the development of educational materials from Mundipharma and Novartis; payment for travel/accommodation/meeting expenses from Aerocrine, AstraZeneca, Boehringer Ingelheim, Mundipharma, Napp, Novartis, and Teva Pharmaceuticals; funding for patient enrollment or completion of research from Chiesi, Novartis, Teva Pharmaceuticals, and Zentiva; stock/stock options from AKL Research and Development Ltd which produces phytopharmaceuticals; owns 74% of the social enterprise Optimum Patient Care Ltd, UK and 74% of Observational and Pragmatic Research Institute Pte Ltd, Singapore; and is peer reviewer for grant committees of the Efficacy and Mechanism Evaluation programme, Health Technology Assessment, and Medical Research Council. Omar S. Usmani reports grants from AstraZeneca, personal fees from Boehringer Ingelheim, grants and personal fees from Chiesi, personal fees from Aerocrine, grants from GlaxoSmithKline, personal fees from Napp, personal fees from Mundipharma, personal fees from Sandoz, grants from Prosonix, personal fees from Takeda, personal fees from Zentiva, grants from Edmond Pharma. He is a recipient of a UK National Institute for Health Research (NIHR) Career Development Fellowship and supported by the NIHR Respiratory Disease Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College London. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Author Contributions

Conceptualization: DBP OSU RM EI DP WvA. Data curation: AB. Formal analysis: AB. Funding acquisition: DBP. Investigation: AB. Methodology: AB. Project administration: DBP. Resources: DBP. Supervision: DBP OSU. Validation: DBP OSU AB. Visualization: SS. Writing – original draft: SS. Writing – review & editing: SS RM EI DP WvA DBP OSU.