Author Contributions: Dr Wennberg 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: Wennberg, Siewers.
Acquisition of data: Wennberg.
Analysis and interpretation of data: Wennberg,
Lucas, Siewers, Kellett, Malenka.
Drafting of the manuscript: Wennberg, Lucas,
Critical revision of the manuscript for important
intellectual content: Wennberg, Lucas, Siewers, Kellett, Malenka.
Statistical analysis: Lucas, Siewers.
Obtained funding: Wennberg.
Administrative, technical, or material support:
Study supervision: Wennberg, Malenka.
Funding/Support: This study was supported in
part by grants from the US Agency for Healthcare Research and Quality and
from the National Institute on Aging.
Role of the Sponsors: The Agency for Healthcare
Research and Quality and the National Institute on Aging did not participate
in the design and conduct of the study, in the collection, analysis, and interpretation
of the data, or in the preparation, review, or approval of the manuscript.