1 Department of Epidemiology and Public Health, University of Maryland School of Medicine & Department of Hospital Epidemiology, Veterans Affairs Maryland Health Care System, Baltimore, Maryland.
2 Robert Wood Johnson Foundation Clinical Scholars Program, Yale University School of Medicine, New Haven, Connecticut.
3 Department of Veterans Affairs, West Haven, Connecticut.
4 Department of Medicine and Center for Health Policy and Outcomes, Memorial-Sloan Kettering Cancer Center, New York, New York.