Long-Term Adherence to Etanercept in Treatment Effectiveness of Patients with Spondyloarthritis: 7-Year Data from the Iraq National Registry

INTRODUCTION: The diagnosis and treatment of spondyloarthritis (SpA) is a global challenge, with no cure available. Adherence to treatment with biologic disease-modifying antirheumatic drugs, such as the tumor necrosis factor-α inhibitor etanercept, varies among patients with SpA. Inadequate or poor adherence to treatment may have a negative effect on clinical outcome and quality of life and may lead to greater health-related expense. METHODS: This observational, retrospective study used real-world patient data from the Iraq National Center of Rheumatology database to retrospectively assess long-term adherence to etanercept, specifically evaluating 1- and 7-year adherence to etanercept among Iraqi patients with SpA. RESULTS: In total, data from 763 patients were included in the analysis. The majority of patients were men (82.2%). Mean disease duration at baseline was 5.85 years; 84.0% of patients received concomitant steroids, and 14.2% were treated with concomitant methotrexate. Measures of disease activity and functional status (mean ± SD) at baseline based on the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Bath Ankylosing Spondylitis Functional Index (BASFI) were 8.06 ± 0.83 (range 6.0–9.5) and 7.75 ± 1.12 (range 4.1–9.7), respectively. Around 30% of patients initiated etanercept treatment within 1 year of diagnosis. After 1 and 7 years, 91.7% (700/763) and 60.6% (80/132) of patients were adherent to etanercept treatment. Mean (± SD) changes from baseline in BASDAI and BASFI scores for adherent versus non-adherent patients at 1 year were 6.73 (± 1.90) versus 4.20 (± 1.85) (p = 0.0001) and 6.43 (± 2.04) versus 4.18 (± 1.88) (p = 0.0001), respectively. CONCLUSIONS: These results suggest that Iraqi patients with SpA benefit from long-term adherence to etanercept treatment; however, additional analyses are needed to further assess the reasons for treatment discontinuation, which may include disease remission. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04507776.