Author Contributions: Dr Stafford 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: Majumdar, Almasi,
Acquisition of data: Stafford.
Analysis and interpretation of data: Majumdar,
Drafting of the manuscript: Majumdar, Stafford.
Critical revision of the manuscript for important
intellectual content: Majumdar, Almasi, Stafford.
Statistical analysis: Stafford.
Obtained funding: Stafford.
Administrative, technical, or material support:
Study supervision: Stafford.
Funding/Support: This study was supported by
research grant R01-HS013405 from the Agency for Healthcare Research and Quality.
Dr Majumdar is a Population Health Investigator supported by the Alberta Heritage
Foundation for Medical Research and a New Investigator supported by the Canadian
Institutes of Health Research. Ms Almasi was supported by a Stanford University
Presidential Scholars Award.
Role of the Sponsors: None of the sponsors
of our research played a role in the design and conduct of this study; collection,
management, analysis, and interpretation of the data; or preparation, review,
and approval of the manuscript.
Acknowledgment: We thank Merck and Co Inc and
IMS Health for providing access to the data used in this analysis. We also
thank Stan Finkelstein, MD, and Iain Cockburn, PhD, for their comments on
an early version of the manuscript.