Adherence to Anti–Tumor Necrosis Factor Therapy Administered Subcutaneously and Associated Factors in Patients With Rheumatoid Arthritis

BACKGROUND: Adherence to biologic therapy is relatively poorly studied in rheumatoid arthritis (RA) because many of the studies have investigated the drug persistence, which represents only a surrogate of adherence. OBJECTIVES: The aims of this study were to determine the extent of adherence in RA patients with subcutaneously administered anti-tumor necrosis factor methotrexate agents and to identify the risk factors for nonadherence. METHODS: A cohort of RA patients who started a subcutaneous anti-tumor necrosis factor treatment were enrolled. After 12 months of treatment, all patients completed the 4-item Morisky Medication Adherence Scale questionnaire. Associations between beliefs and nonadherence and the influence of demographic, clinical, and radiographic features were assessed using logistic regression model. RESULTS: A total of 209 (80.4%) of the 260 patients were included in the analyses. Forty-three of 209 patients were considered nonadherent to their medication (20.6%) according to the 4-item Morisky Medication Adherence Scale. More than half (53.1%) of patients showed at least 1 form of nonadherent behavior.The logistic model showed that low disease activity (P = 0.003), higher patient-physician discordance ratings (P = 0.012), older age (P = 0.041), and a high number of comorbid conditions (P = 0.011) were significantly associated with increased likelihood of nonadherence. CONCLUSIONS: The overall nonadherence with subcutaneous biologic therapy is relatively high among RA patients and should be taken into account when a patient's response to treatment is unsatisfactory.