1. From the Cleveland Clinic Mellen Center for Multiple Sclerosis Treatment and Research (JRA, JAC, MRR), Cleveland Clinic Foundation, Cleveland, OH, USA
2. The Neurological Institute Center for Outcomes Research (BLU), Cleveland Clinic Foundation, Cleveland, OH, USA
3. Quantitative Health Sciences, Lerner Research Institute, Cleveland, OH, USA (BLU)
4. Case Western Reserve University School of Medicine, Cleveland, OH, USA (SB)