Individual Differences in Shared Decision-Making: Does Decision-Making Capacity Affect Collaborative Patient-Provider Interactions?

Background: Medical decision-making can have important implications for patients and families. Shared decision-making (SDM) interventions aim to promote collaboration in patient-provider interactions by building a consensus about preferred treatments, and these show small effects for improving patient-reported outcomes. However, no studies have examined whether individual differences in decision-making moderate the effectiveness of SDM for improving patient decisional conflict after making medical decisions. Method: 89 University of Houston undergraduate students were randomized into an SDM group aimed at maximizing patient-provider collaboration or a control group with minimal collaboration during a simulated medical decision. Participants rated their perceived decisional conflict using the Decisional Conflict Scale. Participants also completed a series of well-validated self-report and performance-based measures of decision-making capacity. Statistical models included moderated multiple regression with terms including each decision-making capacity measure, group status, and the interaction between each decision- making capacity measure and group status predicting decisional conflict. Results: There was no significant group difference between the SDM and control groups for perceived decisional conflict (Cohen’s d=.26). Controlling for gender and its interaction with group, multiple regressions revealed main effects of two aspects of decision-making (i.e., decision-making reasoning, self-reported decisional control/thoroughness) that were associated with lower decisional conflict. Across measures of decision-making capacity, there were no statistically significant interactions between decision-making and SDM group on decisional conflict (all ps > .05). Conclusions: Findings suggest individual differences in some aspects of decision-making capacity are associated with decisional conflict, but they do not modulate the effects of SDM on perceived decisional conflict among healthy young adults. The current study was limited by design (i.e., healthy participants, simulation of medical decisions) and sample size. Future studies might nevertheless examine whether decision-making capacity alters SDM effectiveness for patient-reported outcomes in clinical populations with prevalent decision- making impairment who are confronting real-world medical decisions.