[1] Univ North Texas Hlth Sci Ctr, Dept Epidemiol, Ft Worth, TX USA
[2] Univ Arkansas Med Sci, Dept Epidemiol, Coll Publ Hlth, Little Rock, AR 72205 USA
[3] Michael E DeBakey VA Med Ctr, Dept Med, Sect Gastroenterol & Hepatol, Houston, TX USA
[4] Baylor Coll Med, Dept Med, Michael E DeBakey VA Med Ctr, Houston, TX 77030 USA
[5] Baylor Coll Med, VA HSR&D Ctr Innovat Qual Effectiveness & Safety, Michael E DeBakey VA Med Ctr, Sect Hlth Serv Res, Houston, TX 77030 USA
[6] Univ Padua, Dept Diagnost Med Sci & Special Therapies, Surg Pathol & Cytopathol Unit, Padua, Italy
[7] Baylor Coll Med, Dept Med, Michael E DeBakey VA Med Ctr, Dept Pathol, Houston, TX 77030 USA
[8] Michael E DeBakey VA Med Ctr, Dept Med, Houston, TX USA
[9] Baylor Coll Med, Michael E DeBakey VA Med Ctr, VA HSR&D Ctr Innovat Qual Effectiveness & Safety, Sect Gastroenterol & Hepatol, Houston, TX 77030 USA