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.