Author Contributions: Dr Joynt 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: Joynt, Jha.
Acquisition of data: Jha.
Analysis and interpretation of data: Joynt, Orav, Jha.
Drafting of the manuscript: Joynt.
Critical revision of the manuscript for important intellectual content: Joynt, Orav, Jha.
Statistical analysis: Joynt, Orav.
Administrative, technical, or material support: Jha.
Study supervision: Jha.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Jha has provided consulting support to UpToDate. No other disclosures were reported.
Funding/Support: Dr Joynt was supported by National Institutes of Health Training Grant T32HL007604-24, Brigham and Women's Hospital, Division of Cardiovascular Medicine.
Role of the Sponsor: The funder supported research time for Dr Joynt and did not fund the study directly; thus, the funder 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 Jie Zheng, PhD, from the Department of Health Policy and Management, Harvard School of Public Health, for assistance with statistical programming. Dr Zheng received compensation as part of regular employment.
This article was corrected for errors on February 16, 2011.