Predictors of subclinical shoulder joint affection in patients with rheumatoid arthritis by ultrasonography

Background To assess subclinical involvement of shoulder joints in patients with rheumatoid arthritis (RA) by using musculoskeletal ultrasound (MSUS) and detect their predictors. Results We found 75% of the patients have subclinical ultrasound changes in their shoulder joints where 65% of the patient's shoulders are affected. About 57.5% of the shoulder joints showed peri-articular structural changes by ultrasound, while the articular changes were 36.9% with the most frequent one being supraspinatus tendinopathy (43.12%) followed by subacromial-subdeltoid bursitis [total (31.87%), effusion (16.87%), and synovial hypertrophy (15%)], supraspinatus tendon partial tear (30.62%), and long head of biceps tenosynovitis (effusion only) (28.75%), while the least frequencies were glenohumeral joint erosion (11.25%) and synovitis (12.5%). Older age and longer disease duration were significant predictors for the peri-articular changes with p value < 0.5, while high disease activity, seropositive rheumatoid factor, and long disease duration were significant predictors for the articular changes with p value < 0.5. Conclusion Although shoulders were clinically silent in RA patients, we found a high percentage of subclinical abnormalities detected by MSUS, which were more predominant in the peri-articular structures. MSUS is a simple and non-invasive technique that can be used to detect RA shoulder subclinical affection.