1. Division of Gastroenterology, University of California San Diego, La Jolla, California, USA
2. Division of Biomedical Informatics, University of California San Diego, La Jolla, California, USA
3. Biostatistics Unit, Altman Clinical and Translational Research Institute, University of California San Diego, La Jolla, California, USA
4. Department of Family Medicine and Public Health and Department of Mathematics, University of California San Diego, La Jolla, California, USA