Which of the following statements is true about rheumatoid arthritis?

The statement that rheumatoid arthritis is an insidious chronic autoimmune disease is true. Rheumatoid arthritis (RA) is characterized by the body’s immune system mistakenly attacking the synovium, the lining of the joints, leading to inflammation, pain, and potential joint damage over time. The term "insidious" refers to the gradual and subtle onset of symptoms, which often leads to delays in diagnosis. This chronic condition can persist for years and typically involves fluctuations with periods of exacerbation and remission.

While RA can affect other systems in the body, such as skin, blood vessels, and potentially the lungs and heart, this is not its primary classification. Unlike the choices provided, RA is fundamentally rooted in the immune system's dysfunction, making the assertion that it does not affect the immune system incorrect. Joint issues in rheumatoid arthritis arise from the autoimmune response rather than from simple wear and tear of cartilage as seen in other types of arthritis like osteoarthritis.