A bio-what? Medical companions' perceptions towards biosimilars and information needs in rheumatology.

Patient perceptions influence biosimilar uptake in non-mandatory transitions. Companions (support people) are often actively involved in the patient's medical journey and are likely to have unique perceptions of biosimilars, which may shape patient attitudes. This study explores the congruence between patient and companion perceptions towards biosimilars and their information needs. Patients taking bio-originators for rheumatic diseases (59% for rheumatoid arthritis) and their companions received an explanation about biosimilars. Participants (N = 78) completed questionnaires assessing their familiarity with biosimilars, perceptions, concerns, and benefits of being accompanied. Contingency tables and paired sample t-tests were used to explore differences in familiarity, confidence in knowledge, and perceptions. Intra-class correlation coefficients were calculated to assess the degree of congruence for perceptions towards biosimilars. Companions were significantly less familiar with biosimilars (p = 0.014, Cramer's V = 0.28) and reported lower confidence in their knowledge (p = 0.006, Cohen's d = 0.47) than patients. Companions and patients had moderate to good congruency for perceptions toward confidence in biosimilar use and safety, efficacy, and side-effect expectations (intra-class correlation coefficients ranging from 0.75 to 0.81). Companions and patients were most concerned about safety and effectiveness. Companions also reported concerns about cost savings driving the transition, while patients had concerns about uncertainty and testing. Patients reported the ability for discussion, improved understanding, and validation as benefits of being accompanied. Companions and patients have similar levels of perceptions and expectations towards biosimilars but report some unique information needs. Future educational interventions should involve companions and address their concerns to help improve biosimilar acceptance.