Correlation of BASDAI and BASFI with Clinical Features and Treatment in Chinese Patients with Ankylosing spondylitis

Objective: To understand the relationship between disease activity or patient functional ability with different clinical parameters (e.g. age, gender, age at onset, disease duration) in our ankylosing spondylitis (AS) patients in Taiwan.Methods: Chinese version of Bath ankylosing spondylitis disease activity index (BASDAI) and Bath ankylosing spondylitis functional index (BASFI) was recently developed and validated by our AS Study Group. We enrolled 344 AS patients and analyzed their demographic and clinical characteristics, sulfasalazine and non-steroidal anti-inflammatory drugs (NSAIDs) use, and clinical outcome by using the Chinese version of BASDAI and BASFI.Results: The 344 AS patients were predominantly male (255) (M:F = 2.9:1) and Taiwanese (69.3%). Hakka and Mainlander ethnicity was 13.2% and 12.4%, respectively. Mean age in the study was 36.2 (M ± SD: 36.2 ± 11.95). Although the mean age at onset was 24.98, 35% of patients had onset of AS before 16 yrs. Average BASDAI score in AS patients was 3.2(range 0-8.5), and BASFI 2.55 (range 0-9.32). Uveitis was present in 29.9% patients and peripheral arthritis developed in 66.1% AS patients. Many patients (47.1%) reported that their family relatives also had AS. Correlation analysis between clinical features and BASDAI showed a significant correlation only between peripheral arthritis and BASDAI (p＜0.0001). However, age, age above 35 or below 35 or different age distribution, disease duration, peripheral arthritis and NSAID use, showed a significant correlation with BASFI.Conclusion: The presence of peripheral arthritis can significantly influence both BASDAI and BASFI. The old age, longer disease duration and continuous treatment with NSAIDs was associated with a higher score in BASFI but not BASDAI. Early diagnosis and adequate management may prevent AS patients from later functional impairment.