Author Contributions: Dr DeVoe and Ms Tillotson had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: DeVoe, Wallace.
Acquisition of data: Tillotson.
Analysis and interpretation of data: DeVoe, Tillotson, Wallace.
Drafting of the manuscript: DeVoe.
Critical revision of the manuscript for important intellectual content: DeVoe, Tillotson, Wallace.
Statistical analysis: Tillotson.
Obtained funding: DeVoe.
Administrative, technical, or material support: DeVoe, Wallace.
Study supervision: DeVoe.
Financial Disclosures: None reported.
Funding/Support: Dr DeVoe's time on this project was supported by grant 1 K08 HS16181 from the Agency for Healthcare Research and Quality (AHRQ). Ms Tillotson is employed by the Biostatistics Shared Resource of Oregon Health and Science University and by the Oregon Clinical and Translational Research Institute (OCTRI) and is supported by grant UL1 RR024140 01 from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH), and NIH Roadmap for Medical Research.
Role of the Sponsor: These funding agencies had no involvement in the design and conduct of the study; analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. AHRQ collects and manages the Medical Expenditure Panel Survey.
Additional Contributions: Julie Hudson, PhD, and Jessica Vistnes, PhD, from the AHRQ were extremely helpful in guiding our statistical programming. We are grateful to Eun Sul Lee, PhD, Oregon Health Science University, and Ed Fryer, PhD, Department of Pediatrics, New York University, for sharing their biostatistical expertise. No one received compensation for their assistance.