Department of Internal Medicine, Hamad Medical Corporation, P.O 3050, Doha, Qatar.Department of Internal Medicine, Hamad Medical Corporation, P.O 3050, Doha, Qatar.Department of Rheumatology, Hamad Medical Corporation, P.O 3050, Doha, Qatar.Department of Internal Medicine, Hamad Medical Corporation, P.O 3050, Doha, Qatar.