Affiliation: | 1.Department of Medicine,VA Greater Los Angeles Healthcare System,Los Angeles,USA;2.VA HSR&D Center for the Study of Healthcare Innovation,Implementation and Policy,Los Angeles,USA;3.David Geffen School of Medicine,University of California,Los Angeles,USA;4.Jonathan and Karin Fielding School of Public Health,University of California,Los Angeles,USA;5.Division of Research,Kaiser Permanente Northern California,Oakland,USA;6.UnitedHealthcare,Minnetonka,USA |