1. Department of Population Health SciencesDuke University School of Medicine Durham NC USA
2. Duke Clinical Research InstituteDuke University Durham NC USA
3. Department of Health Policy and ManagementUniversity of North Carolina Gillings School of Global Public Health Chapel Hill NC USA
4. Division of ResearchKaiser Permanente North California Oakland, CA USA
5. Department of Population HealthUniversity of Kansas Medical Center Kansas City KS USA
6. Department of AnesthesiologyUniversity of Kansas Medical Center Kansas City KS USA