1. Department of Medicine, VA North Texas Health Care System, Dallas, TX, USA
2. Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
3. Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
4. College of Pharmacy, The University of Texas at Austin, San Antonio, TX, USA
5. Department of Medicine, School of Medicine, University of Texas Health Science Center, San Antonio, TX, USA