Published Online: December 23, 2013. doi:10.1001/jamainternmed.2013.13426.
Study concept and design: Thilen, Treggiari, Weaver, Wijeysundera.
Acquisition of data: Thilen.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Thilen, Lange, Wijeysundera.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Thilen, Lange, Lowy, Wijeysundera.
Obtained funding: Thilen.
Study supervision: Treggiari, Weaver, Wijeysundera.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was partially supported by funds from the Department of Anesthesiology and Pain Medicine, University of Washington, Seattle. Dr Thilen is supported by grant T32GM086270 from the National Institutes of Health, and by the Department of Anesthesiology and Pain Medicine, University of Washington, Seattle. Dr Wijeysundera is supported by a Clinician Scientist Award from the Canadian Institutes of Health Research and a Merit Award from the Department of Anesthesia at the University of Toronto, Toronto, Ontario, Canada. Drs Weaver and Lowy are partially supported by resources from the Veterans Affairs Puget Sound Health Care System, Seattle, Washington.
Role of the Sponsors: The funders had no role in the design and conduct of the study; collection, management, analysis, or interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Previous Presentation: Preliminary data were presented at the annual meeting of the International Anesthesia Research Society; May 4, 2013; San Diego, California.
Additional Contributions: William Kreuter, MPA, Department of Health Services, School of Public Health, University of Washington, Seattle, assisted with computer programming and served as custodian of the original Medicare data files. He received financial compensation for his contributions to this study.