Study concept and design: All authors.
Acquisition, analysis, or interpretation of data: Liu.
Drafting of the manuscript: Liu.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Liu.
Obtained funding: Liu.
Administrative, technical, or material support: Musen.
Study supervision: Chou.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: Dr Liu was supported by the Permanente Medical Group and grant K23 GM112018 from the National Institutes of Health.
Role of the Funder/Sponsor: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript, and decision to submit the manuscript for publication.
Correction: This article was corrected on May 21, 2015, to fix wording and data errors in the text and Table.