1. Division of Gastroenterology and Hepatology University of Washington Seattle WA USA
2. Health Service Research and Development Veterans Affairs Puget Sound Health Care System Seattle WA USA
3. Division of Gastroenterology and Hepatology University of North Carolina Chapel Hill NC USA
4. Department of Health Services University of Washington Seattle WA USA
5. Division of Gastroenterology Veterans Affairs Puget Sound Health Care System Seattle WA USA