Adherence to subcutaneous anti-TNFα agents in patients with rheumatoid arthritis is largely influenced by pain and skin sensations at the injection site

AIM: The aims of this prospective study were to determine the dimension of adherence in rheumatoid arthritis (RA) patients receiving subcutaneously administered anti-tumor necrosis factor-α (anti-TNFα) agents and to evaluate the influence of injection site pain and skin perceptions following subcutaneous administration of anti-TNFα drugs on patients' adherence. METHOD: An inception cohort of patients starting subcutaneously administered anti-TNFα treatment was enrolled. Injection site pain perception was assessed through the Self-Injection Assessment Pain Questionnaire (SIAPQ), and adherence to treatment was ascertained by the Compliance Questionnaire for Rheumatology (CQR5). Associations between beliefs and non-adherence, and the influence of demographic (age, disease duration, educational level), clinical (body mass index, patient global assessment, physician global assessment, Numerical Rating Scale of pain, Health Assessment Questionnaire-Disability Index, Simplified Disease Activity Index, and comorbidities measured by the modified Rheumatic Disease Comorbidty Index), and radiographic (Simple Erosion Narrowing Score) variables were assessed using logistic regression models. RESULTS: Adherence data over a 12-month interval were available for 193 patients. Of these, 21.7% reported non-adherence to anti-TNFα therapy. No difference (P = .383) was found for anti-TNFα drugs (adalimumab, etanercept, certolizumab pegol and golimumab). In the logistic model, age (P = .0029), higher disease activity (P = .020), low numbers of comorbidity conditions (P = .0004), injection site pain and skin perception (P = .0008), were significantly associated with increased likelihood of medication adherence. CONCLUSION: Adherence is influenced by both demographic characteristics (age) and clinical factors (disease activity, comorbidity burden and injection site pain and skin perception) in RA patients.