Submitted for Publication: September 17, 2013; accepted October 9, 2013.
Published Online: November 28, 2013. doi:10.1001/jamaoto.2013.5859.
Study concept and design: Chun, Preciado, Brown, Ishman, Kerschner, Richter.
Acquisition of data: Chun, Preciado, Brown, Elluru, Kerschner.
Analysis and interpretation of data: Chun, Preciado, Brown, Ishman, Kerschner, Richter, Sulman.
Drafting of the manuscript: Chun, Kerschner, Richter.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Chun, Preciado.
Administrative, technical, or material support: Brown, Kerschner, Sulman.
Study supervision: Chun, Preciado, Elluru, Kerschner, Richter
Conflict of Interest Disclosures: None reported.
Additional Contributions: Shi Zhao, PhD, and Sergey Tarima, PhD, Division of Biostatistics, Medical College of Wisconsin, provided assistance in statistical analysis. They were not compensated for their contributions.