Published Online: December 11, 2013. doi:10.1001/jamasurg.2013.3649.
Study concept and design: Dimick, Birkmeyer, Ghaferi.
Acquisition of data: Ghaferi.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Gonzalez, Ghaferi.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: All authors.
Obtained funding: Dimick.
Administrative, technical, or material support: Dimick, Birkmeyer, Ghaferi.
Study supervision: Birkmeyer, Ghaferi.
Conflict of Interest Disclosures: Drs Dimick and Birkmeyer are consultants and equity owners in ArborMetrix, an Ann Arbor–based health care analytics and information technology firm. No other disclosures were reported.
Funding/Support: This study was supported by career development award K08 HS017765 from the Agency for Healthcare Research and Quality (Dr Dimick), grant R01 CA098481 from the National Cancer Institute (Dr Birkmeyer), and Ruth L. Kirschstein National Research Service Award training grants T32 CA009672 from the National Cancer Institute (Dr Ghaferi) and T32 HL076123-09 from the National Heart, Lung, and Blood Institute (Dr Gonzalez).
Role of the Sponsor: ArborMetrix and the funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Correction: This article was corrected online December 19, 2013, for an error in the Discussion section.