1. Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, P.R. China
2. Center of Evidence-Based Medicine, Fudan University, Shanghai, P.R. China
3. Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, P.R. China
4. Department of Gastroenterology, Anhui Provincial Hospital, Hefei, Anhui, P.R. China
5. Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, P.R. China
6. Department of Biostatistics, School of Public Health, Fudan University, Shanghai, P.R. China