1. Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei 10015, Taiwan;
2. Department of Medical Research, National Taiwan University Hospital, Taipei 10015, Taiwan
3. Dipartimento di Medicina Clinica e Sperimentale and Dipartimento di Scienze Mediche, Chirurgiche e Sperimentali, University of Sassari, 07100 Sassari, Italy;
4. Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA;
5. Department of Medicine, Michael E. DeBakey VA Medical Center, Houston, Texas 77030, USA