1. From the Department of Medicine, Medical University of South Carolina, Charleston, SC (B.M.E., Y.Z., J.L., W.A.B., T.M.T.); Department of Medicine, University of Michigan, Ann Arbor, MI (R.D.B.); Department of Medicine, University of Alabama at Birmingham (D.A.C.); and Department of Mathematics, College of Charleston, Charleston, SC (J.L.).