Author Contributions: Dr Dial had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Dial, Barkun, Suissa.
Acquisition of data: Suissa.
Analysis and interpretation of data: Dial, Delaney, Barkun, Suissa.
Drafting of the manuscript: Dial, Barkun, Suissa.
Critical revision of the manuscript for important intellectual content: Delaney, Barkun, Suissa.
Statistical analysis: Dial, Delaney, Suissa.
Obtained funding: Suissa.
Administrative, technical, or material support: Suissa.
Study supervision: Suissa.
Financial Disclosures: Dr Barkun is a consultant for AstraZeneca Inc and Altana Pharma Inc. No other authors reported financial disclosures.
Funding/Support: This study was funded by the Canadian Institutes of Health Research (CIHR) and the Canadian Foundation for Innovation (CFI). Dr Dial is a Chercheur-Boursier Clinicien and Dr Barkun a Chercheur National awardee, both from the Fonds de la recherche en santé du Québec (FRSQ). Dr Suissa is the recipient of a Distinguished Investigator award from CIHR.
Role of the Sponsor: The funding institutes were not involved in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.
Acknowledgment: We thank Dick Menzies, MD, MSc, Montreal Chest Institute for his review of the manuscript and Diane Gaudreau, Royal Victoria Hospital clinical epidemiology unit for secretarial assistance.