Decentralised clinical trials (DCTs) can span multiple countries, each with distinct healthcare systems that shape the availability of patient support services and information. These variations influence both recruitment and retention of participants. Standardised tools, such as consent forms and clinician discussions, often fail to address country-specific needs. To inform the development of a Patient Companion application as a digital support tool, this study investigates how clinicians across six European countries perceive and prioritise the factors influencing patients’ decisions to enrol in and remain part of a DCT. Drawing on interviews, we examine how local healthcare conditions influence these perceptions and evaluate the applicability of evidence-based recommendations. The findings reveal notable cross-country differences in patient needs and existing support structures. Based on these insights, we identified recommendations that were validated, redundant, or missing according to local contexts. These results inform the adaptation of the Patient Companion App to better support patient participation in DCTs.