1. Department of Internal Medicine, College of Medicine, Shaqra University, Shaqra, Saudi Arabia
2. College of Medicine, Al Imam Mohammad Ibn Saud Islamic University, Riyadh, Saudi Arabia
3. Department of Medicine, King Fahd Hospital, Jeddah, Saudi Arabia
4. College of Medicine, King Saud University, Riyadh, Saudi Arabia
5. Sultan Qaboos University, Sultan Qaboos University Hospital, Oman