[1] Univ Penn, Dept Neurol, Perelman Sch Med, Philadelphia, PA 19104 USA
[2] Univ Penn, Translat Ctr Excellence Neurol Outcomes Res, Perelman Sch Med, Philadelphia, PA 19104 USA
[3] Univ Penn, Ctr Clin Epidemiol & Biostat, Perelman Sch Med, Philadelphia, PA 19104 USA
[4] Univ Penn, Dept Biostat Epidemiol & Informat, Perelman Sch Med, Philadelphia, PA 19104 USA
[5] Univ Penn, Leonard Davis Inst Hlth Econ, Perelman Sch Med, Philadelphia, PA 19104 USA