Cooperative Studies Program Coordinating Center, VA Boston Healthcare System, Boston, MA, United States of America; Department of Biostatistics, Boston University School of Public Health, Boston, MA, United States of America. Electronic address: Sarah.Leatherman@va.gov. Cooperative Studies Program Coordinating Center, VA Boston Healthcare System, Boston, MA, United States of America. Pharmacy Benefits Management Services, Department of Veterans Affairs, Washington DC, United States of America; VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States of America; David Geffen School of Medicine at UCLA, Los Angeles, CA, United States of America. Michael E. DeBakey VA Medical Center, Houston, TX, United States of America; Baylor College of Medicine, Department of Medicine, Houston, TX, United States of America. Cooperative Studies Program Coordinating Center, VA Boston Healthcare System, Boston, MA, United States of America; Department of Medicine, Boston University School of Medicine, Boston, MA, United States of America. Medical Service, Memphis VA Medical Center, Memphis, TN, United States of America; Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, TN, United States of America. Minneapolis VA Healthcare System, Minneapolis, MN, United States of America; Department of Medicine, University of Minnesota, Minneapolis, MN, United States of America.