1. Department of Biostatistics, Erasmus MC, Rotterdam, The Netherlands
2. Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
3. Palliative and Advanced Illness Research (PAIR) Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
4. Pulmonary, Allergy, and Critical Care Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
5. Division of Biostatistics, Department of Public Health Sciences, University of Virginia, Charlottesville, VA, USA