1. University Diabetes Center, College of Medicine, King Saud University, P.O. Box 18397, Riyadh 11415, Saudi Arabia
2. Department of Medicine, College of Medicine, King Saud University, P.O. Box 2925, Riyadh 11461, Saudi Arabia
3. Registry Department, University Diabetes Center, King Saud University, P.O. Box 245, Riyadh 11411, Saudi Arabia
4. Department of Biostatistics, Epidemiology and Scientific Computing, King Faisal Specialist Hospital and Research Center, P.O. Box 3345, Riyadh 11211, Saudi Arabia
5. Biostatistics Department, University Diabetes Center, King Saud University, P.O. Box 245, Riyadh 11411, Saudi Arabia