1. Center for Innovations in Quality, Effectiveness and Safety (IQuESt) Michael E. DeBakey Veterans Affairs Medical Center Houston Texas USA
2. Section of Health Services Research Department of Medicine Baylor College of Medicine Houston Texas USA
3. Section of Gastroenterology and Hepatology Department of Medicine Baylor College of Medicine and Michael E. DeBakey Veterans Affairs Medical Center Houston Texas USA
4. Department of Biostatistics University of Texas MD Anderson Cancer Center Houston Texas USA