1. a Center for AIDS Prevention Studies, Department of Medicine, Division of General Internal Medicine , University of California , San Francisco
2. b Department of Epidemiology and Public Health, Department of Psychology , Yale University , New Haven , Connecticut
3. c VA San Diego Healthcare System, Department of Medicine , University of California , San Diego
4. d Department of Internal Medicine, Division of Infectious Diseases, College of Medicine and Public Health , The Ohio State University , Columbus , Ohio
5. e Department of Medicine, Division of Infectious Disease , Indiana University , Indianapolis , Indiana
6. f Department of Health Policy and Management , Johns Hopkins University , Baltimore , Maryland , USA