Early Tumor Necrosis Factor α Antagonist Therapy in Everyday Practice for Inflammatory Back Pain Suggesting Axial Spondyloarthritis: Results From a Prospective Multicenter French Cohort

Objective. To determine the frequency of and factors associated with early tumor necrosis factor alpha (TNF alpha) antagonist therapy in everyday clinical practice in patients with suspected axial spondyloarthropathy (SpA). Methods. We used data from the prospective observational study in the French Devenir des Spondylarthropathies Indifferenciees Recentes (DESIR; Outcome of Recent Undifferentiated Spondylarthropathies) cohort of 708 patients with recent-onset (<3 years) inflammatory back pain (IBP) suggesting axial SpA. TNF alpha antagonist use was recorded at months 6 and 12 and factors independently associated with TNF alpha antagonist therapy were identified by multivariate logistic regression. Results. Among the 708 patients (mean age 33.8 years, 46.2% men), 166 (23.4%) patients received TNF alpha antagonist therapy by month 12, including 120 (73.6%) patients who fulfilled Assessment of SpondyloArthritis international Society (ASAS) axial criteria and 157 (94.6%) who fulfilled at least 1 SpA criteria set; 109 (65.6%) had no sacroiliitis. Factors independently associated with early TNF alpha antagonist therapy were high Ankylosing Spondylitis Disease Activity Score using the C-reactive protein level (odds ratio [OR](1-point increase) 1.60, 95% confidence interval [95% CI] 1.25-2.03, P < 0.001), high physician's global disease activity score (OR 1.37, 95% CI 1.21-1.54, P < 0.001), ASAS nonsteroidal antiinflammatory drug score >50 (OR 1.88, 95% CI 1.24-2.87, P = 0.003), current or past disease-modifying antirheumatic drug use (OR 2.09, 95% CI 1.22-3.59, P = 0.008), systemic corticosteroid use (OR 2.48, 95% CI 1.43-4.34, P = 0.002), and mild to severe radiographic hip abnormalities (OR 9.43, 95% CI 2.11-42.09, P = 0.003). After adjustment on these factors, Achilles enthesis hypervascularization by power Doppler and number of work days missed were associated with TNF alpha antagonist therapy. Conclusion. In the DESIR cohort, approximately one-fourth of patients with recent IBP suggestive of axial SpA were under anti-TNF alpha therapy after 1 year of followup. All factors associated with this early initiation reflected higher disease activity, refractoriness, or severity, which suggests compliance of French rheumatologists with current treatment guidelines.