Objective: To evaluate the role of magnetic resonance imaging (MRI) in predicting a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) improvement of at least 50% (BASDAI 50) upon anti-TNF therapy of active ankylosing spondylitis (AS).
Methods: MRIs from patients with active AS who participated in randomized controlled trials were analyzed with respect to presence and extent of active inflammatory lesions as detected in the spine (n=46), sacroiliac (SI) joints (n=42), and both sites (n=26). Univariate and multivariate logistic regression analyses were applied to evaluate MRI and clinical data in predicting a BASDAI 50 response.
Results: The Berlin MRI spine score (OR 1.16, 95% CI 1.02-1.33) and disease duration (OR 0.9, 95% CI 0.63-0.97) were statistically significant predictors of a BASDAI 50 response using regression analysis while there was only a trend for CRP. The likelihood ratio (LR) for achievement of BASDAI 50 was increased in patients with a Berlin MRI spine score ≥ 11 (LR 6.7), disease duration < 10 years (LR 4.2), and CRP ≥ 40 mg/l (LR 3.4). All patients with 2 or 3 of these predictors improved clinically (BASDAI) by at least 45%. Disease duration >20 yrs, normal CRP, and no active inflammatory lesion in the spine were highly predictive of not achieving BASDAI 50. A trend only was found for the MRI score of SI joints to be predictive.
Conclusions: Widespread inflammation in the spine as detected by MRI contributes to predicting a BASDAI 50 response in active AS patients treated with anti-TNF agents.
- TNF alpha
- ankylosing spondylitis