1. Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics Perelman School of Medicine, University of Pennsylvania Philadelphia Pennsylvania USA
2. Department of Biostatistics, Epidemiology, and Informatics Perelman School of Medicine, University of Pennsylvania Philadelphia Pennsylvania USA
3. Leonard Davis Institute of Health Economics, University of Pennsylvania Philadelphia Pennsylvania USA
4. Department of Biostatistics T.H. Chan School of Public Health, Harvard University Boston Massachusetts USA