1 Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
2 Palliative and Advanced Illness Research (PAIR) Center at the Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
3 Leonard Davis School of Economics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
4 Division of Traumatology, Surgical Critical Care and Emergency Surgery, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.