Author Contributions: Dr Alibhai 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: Alibhai, Cheung, Paszat.
Acquisition of data: Alibhai, Yun, Paszat.
Analysis and interpretation of data: Alibhai, Yun, Cheung, Paszat.
Drafting of the manuscript: Alibhai, Paszat.
Critical revision of the manuscript for important intellectual content: Yun, Cheung.
Statistical analysis: Yun, Paszat.
Obtained funding: Alibhai.
Administrative, technical or material support: Paszat.
Study supervision: Alibhai, Paszat.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: Financial support was provided in part by the Toronto General & Toronto Western Hospital Research Foundation. Dr Alibhai is a research scientist of the Canadian Cancer Society. Dr Cheung is supported by a senior investigator award from the Canadian Institutes of Health Research.
Role of the Sponsors: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; or preparation, review, or approval of the manuscript.
Additional Contributions: We thank Rinku Sutradhar, PhD, and Peter Austin, PhD (both with the Institute for Clinical Evaluative Sciences in Toronto, Ontario, Canada) for providing advice about statistical analyses. No financial compensation was paid for their work.