Is Three a Crowd? The Influence of Companions on a Patient's Decision to Transition to a Biosimilar

Involving patients in treatment decisions is commonplace in healthcare, and patients are frequently accompanied by a companion (support person). Companions are often actively involved in medical consultations, yet their impact on decisions to change medications is unknown.

This study examines the influence of companions on a patient's decision to transition from their bio-originator therapy to a biosimilar.

A parallel, two-arm randomized controlled trial was conducted with 79 patients taking a bio-originator for rheumatic diseases who regularly attend clinic with a companion. Patients were randomized to receive an explanation about a hypothetical transition to a biosimilar alone or with their companion. Patients reported willingness to transition, risk perceptions, difficulty understanding, social support, and completed the Decisional Conflict Scale and Satisfaction with Decision Scale.

Companions did not influence decisions to transition to biosimilars or cognitive and affective risk perceptions. Accompanied patients reported more difficulty understanding the explanation (p = .006, Cohen's d = .64) but thought it was more important to receive information with companions (p = .023, Cohen's d = -.52). Companions did not impact decision satisfaction or decisional conflict. Receiving emotional, but not practical support, was associated with less decisional conflict in accompanied patients (p = .038, r2 = 0.20).

The presence of companions does not seem to influence risk perceptions or decisions about transitioning to biosimilars. Companions, however, impact the patient's reporting of their ability to understand treatment explanations. Providers should check understanding in all patients but may need to provide additional time or educational resources to accompanied patients and companions.

Australian New Zealand Clinical Trial Registry: ACTRN12619001435178.