1. The First Hospital of Lanzhou University, The Evidence-Based Medicine Center of Lanzhou University, Lanzhou, China
2. The Evidence-Based Medicine Center of Lanzhou University, Lanzhou, China
3. The Second Hospital of Lanzhou University, Key Laboratory of Digestive System Tumors, Gansu Province, Lanzhou, China
4. Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, USA
5. The School of Economics of Lanzhou University, Lanzhou, Gansu, China