I have Rheumatoid Arthritis and Sjögren's Syndrome.
Many people do.
Many people with RA develop another autoimmune disease such as Sjögren's Syndrome, lupus, or vasculitis.
When someone with an established autoimmune disease, such as rheumatoid arthritis or lupus, develops extreme dryness of the eyes and mouth it is Secondary Sjögren's Syndrome. When someone has Sjögren's Syndrome and no other autoimmune condition it is called Primary Sjögren's.