What are the key clinical features that differentiate rheumatoid arthritis from osteoarthritis in a primary care setting?

Key clinical features differentiating rheumatoid arthritis (RA) from osteoarthritis (OA) in primary care:

• Joint involvement: RA typically affects the small joints of the hands and feet and usually involves more than one joint, whereas OA commonly affects larger weight-bearing joints such as the hips, knees, and shoulders, as well as the hands but with a different pattern NICE CKS,NICE NG226.
• Onset and symptoms: RA presents with persistent synovitis, joint swelling, tenderness, and prolonged morning stiffness lasting more than 30 minutes, while OA is characterized by activity-related joint pain with either no morning stiffness or stiffness lasting no longer than 30 minutes NICE CKS,NICE NG226.
• Inflammatory signs: RA is an inflammatory arthritis with signs of active inflammation such as joint swelling, warmth, and systemic symptoms like fatigue, whereas OA is a degenerative joint disease with less prominent inflammation and no systemic features NICE CKS,NICE NG226.
• Symptom duration before presentation: RA patients often have a delay of 3 months or longer before seeking medical advice, and early referral is recommended if persistent synovitis is present, regardless of blood test results NICE CKS,NICE NG100. OA diagnosis is clinical and usually does not require imaging unless atypical features are present NICE NG226.
• Morning stiffness duration: RA morning stiffness typically lasts longer than 30 minutes, whereas OA morning stiffness is brief, usually less than 30 minutes NICE NG226.
• Joint deformity and progression: RA can cause progressive joint deformity and loss of function due to erosive synovitis, while OA leads to joint space narrowing and osteophyte formation without systemic inflammation NICE CKS,NICE NG226.