1. Sleep Medicine Research Group, Sleep Medicine and Research Center, King Abdulaziz University Hospital, Jeddah, Saudi Arabia;
2. Department of Medicine, Rheumatology Unit, University of Jeddah, Jeddah, Saudi Arabia;
3. Department of Nursing, College of Applied Medical Sciences, Majmaah University, Majmaah, Saudi Arabia;
4. Department of Medicine, Rheumatology Unit, King Abdulaziz University, Jeddah, Saudi Arabia;
5. Tameside Hospital, Ashton-under-Lyne, United Kingdom