Patients' beliefs and behaviours are associated with perceptions of safety and concerns in a hypothetical biosimilar switch.

Although patient acceptance is important for biosimilar adoption and reducing healthcare costs, many patients perceive biosimilars to be unsafe and have concerns about switching. Studies show that patients' characteristics influence negative perceptions toward generic drugs, but little research has explored biosimilar acceptance. This study examines which demographic and psychological characteristics are associated with patients' safety perceptions and concerns about switching to biosimilars. Ninety-six patients taking bio-originators for rheumatic conditions (65% for rheumatoid arthritis) completed the Brief Illness Perceptions Questionnaire, Beliefs about Medicines Questionnaire and Perceived Sensitivity to Medicines Scale. Demographic factors, information seeking, concerns about switching and safety perceptions were also assessed. Pearson's correlations and hierarchical linear regressions were conducted to explore whether patient characteristics are associated with perceptions of biosimilars. Negative safety perceptions were associated with being female, short-term bio-originator use, illness beliefs, seeking health information online, high perceived sensitivity to medicines and negative beliefs about medicines. Only being female (β = 0.24, P = 0.02) was independently associated. More concerns about switching were associated with being female, illness beliefs, high perceived sensitivity to medicines, information-seeking behaviours and preferring innovator drugs. Seeking health information online (β = 0.20, P = 0.04), preferring innovator drugs (β = 0.29, P = 0.004) and stronger emotional responses (β = 0.26, P = 0.01) were independently associated. Perceived bio-originator effectiveness was inversely associated with preferring biosimilars (rs=  - 0.33, P < 0.001). Patients who have stronger emotional responses to their condition, are females, seek health information online and prefer innovator drugs that have more negative perceptions about biosimilars. Experiences with bio-originators influence attitudes towards switching.