RA vs OA: ① RA = autoimmune (immune system attacks joints), ② OA = wear-and-tear, age-related, ③ RA: symmetric, multiple joints, morning stiffness >1 hour, systemic symptoms, ④ OA: asymmetric, weight-bearing joints, brief stiffness, ⑤ blood tests differentiate. RA needs immunosuppressants + Korean medicine; OA Korean medicine alone often sufficient.