Determinants of Preferences for Family Involvement in Medical Decision Making: A Vignette-Based Study on a Subsample of The Social Study in Belgium

BACKGROUND: Family involvement (FI) in medical decision making (MDM) is increasingly recognized as a dimension of patient-centered care; however, patient preferences for FI vary across clinical and cultural contexts. In health care systems emphasizing autonomy and direct communication, less is known about how patient characteristics and illness scenarios (cancer vs depression; and mild vs severe depression) influence FI preferences. METHODS: = 1,175) collected in 2024. In a survey experiment, respondents evaluated vignettes describing skin cancer and depression; the depression vignette was randomly assigned as mild or severe. Ordered logistic regression models assessed associations between FI preferences and sociodemographic and economic factors as well as religious affiliation. RESULTS: Preference for family-led decision making was uncommon across vignettes (skin cancer: 1.2%; severe depression: 2.7%; mild depression: 1.4%), while the majority preferred patient-led decision making (77.4%, 70.9%, and 81.0%, respectively). Making medical decisions together with family members was most often preferred in cases of severe depression (26.4%), followed by cancer (21.4%) and mild depression (17.6%). Living with a partner and having a migration background (European or non-European) were associated with a greater preference for FI. Respondents identifying as Christian (vs nonreligious/liberal) showed stronger preferences for FI in the cancer and severe depression vignette. Higher educational attainment was associated with weaker preferences for FI, particularly in the cancer vignette. CONCLUSIONS: Preferences for family-led decision making were low, with most respondents favoring autonomous decision making. FI preferences varied modestly by illness context and sociodemographic characteristics, particularly migration background, living situation, education, and religious affiliation. These findings underscore the importance of flexible MDM approaches that accommodate heterogeneity in patient preferences.