Clinical characteristics of patients with ankylosing spondylitis in India.

This study focuses on describing full spectrum of clinical, laboratory, and radiological characterization of ankylosing spondylitis (AS) patients in India. Data on 70 consecutive AS patients, seen at the rheumatology clinic in India, was prospectively obtained using investigator-administered questionnaires. Diagnosis was made according to the modified New York criteria. The core set of variables selected by Assessment in AS International society were obtained. The differences in clinical characteristics based on presence or absence of peripheral arthritis, gender, and juvenile (JOAS) vs. adult onset AS (AOAS) were evaluated. The male/female ratio was 5:1. The mean age of onset of symptoms and diagnosis were 23.6 and 32.5 years, respectively. Females had similar spinal indices and radiological damage as male counterpart. However, they had more common extra-articular manifestations and root joint involvement. The majority of patients consisted of AOAS (78.5%) and was clinically similar to JOAS. One or more peripheral joints were involved in 65.7% of patients, affecting predominantly the lower extremity (90.6%, knee 47.1%, and ankle 35.7%) in asymmetrical pattern (78%). Patients with peripheral arthritis had higher erythrocyte sedimentation rate, more frequent enthesitis, root joint, and whole spine involvement, suggesting more aggressive disease. Most common site of enthesitis was chondro-sternal junction (30%) and Achilles tendonitis (24.3%). The root joints frequently involved extra-axial joints. Uveitis was the most common extra-articular manifestation (25.7%). The predominant initial symptom was typical inflammatory low back pain (87.1%). Assessment in ankylosing spondylitis indices showed a moderately severe disease activity and damage with following values: mean Bath Ankylosing Spondylitis Disease Activity Index, 3.2 (+/-1.8); mean Bath Ankylosing Spondylitis Functional Index, 2.3 (+/-2.0); and mean Bath Ankylosing Spondylitis Metrology Index, 3.15 (+/-2.3). Majority of the patients had bilateral sacroiliitis (grades 2-4) on radiographs (87.1%). In conclusion, the features of AS in Indian patients were broadly similar to other part of world, with the exception of increased frequency of peripheral arthritis.