1. Medical Practice Evaluation Center, Massachusetts General Hospital, Boston, MA, USA
2. Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA
3. Harvard University Center for AIDS Research (CFAR), Boston, MA, USA
4. Harvard Medical School, Boston, MA, USA
5. Desmond Tutu HIV Centre, Institute of Infectious Disease & Molecular Medicine and Department of Medicine Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
6. Biostatistics Center, Massachusetts General Hospital, Boston, MA, USA