Objective: Communication about patients' values, goals, and prognosis in serious illness (serious illness communication) is a cornerstone of person-centered care yet difficult to implement in practice. As part of Serious Illness Care Program implementation in five health systems, we studied the clinical culture-related factors that supported or impeded improvement in serious illness conversations.

Methods: Qualitative analysis of semi-structured interviews of clinical leaders, implementation teams, and frontline champions.

Results: We completed 30 interviews across palliative care, oncology, primary care, and hospital medicine. Participants identified four culture-related domains that influenced serious illness communication improvement: (1) clinical paradigms; (2) interprofessional empowerment; (3) perceived conversation impact; (4) practice norms. Changes in clinicians' beliefs, attitudes, and behaviors in these domains supported values and goals conversations, including: shifting paradigms about serious illness communication from 'end-of-life planning' to 'knowing and honoring what matters most to patients;' improvements in psychological safety that empowered advanced practice clinicians, nurses and social workers to take expanded roles; experiencing benefits of earlier values and goals conversations; shifting from avoidant norms to integration norms in which earlier serious illness discussions became part of routine processes. Culture-related inhibitors included: beliefs that conversations are about dying or withdrawing care; attitudes that serious illness communication is the physician's job; discomfort managing emotions; lack of reliable processes.

Conclusions: Aspects of clinical culture, such as paradigms about serious illness communication and inter-professional empowerment, are linked to successful adoption of serious illness communication. Further research is warranted to identify effective strategies to enhance clinical culture and drive clinician practice change.