1 Division of Health Policy and Insurance Research, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Landmark Center, 401 Park Drive Suite 401, Boston, MA, 02215, USA. christleopold@gmx.net.
2 Division of Health Policy and Insurance Research, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Landmark Center, 401 Park Drive Suite 401, Boston, MA, 02215, USA.
3 Department of Oncology and Hematology, Atrius Health, Boston, MA, USA.
4 Department of Health Behavior and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA.