These two types of joint disease are frequently confused in the general population. Osteoarthritis is a disease that develops over time due to the stress placed on the joints as a result of aging, weight, past illnesses, and other factors. Rheumatoid arthritis, on the other hand, is a condition characterized by inflammation of the joints due to a disorder of the immune system. These two ailments share a similarity in that they both cause pain and discomfort.