1. Department of Medicine, Division of General Internal Medicine, University of California, San Francisco, California.
2. Department of Obstetrics and Gynecology, University of California, San Francisco, California.
3. Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California.
4. General Internal Medicine Section, Department of Veterans Affairs, University of California, San Francisco, California.
5. Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, California.
6. Institute for Health Policy Studies and Department of Surgery, University of California, San Francisco, California.