Shared decision making
helplessness/hopelessness, anxiety
To model the relation between observed SDM and adverse outcomes, we fit a multivariate model that included all adverse outcomes at the first follow-up measurement (T2) as outcome variables (anxiety, tension, helplessness/hopelessness, loss of fighting spirit, uncertainty) and observed SDM as well as baseline scores of all adverse outcomes as independent variables. Including baseline adverse outcomes (T0) in the model allowed us to control for baseline differences between patients. For tension, the measurement shortly before the consultation in the waiting room (T1) was considered the baseline. For uncertainty, no preconsultation baseline measurements were available.To test if the relationship between SDM and adverse outcomes was moderated by preferred role in decision making and type of conversation, we also tested for multivariate interactions. In univariate analyses of SDM and each of the separate adverse outcomes, we controlled only for the corresponding baseline adverse outcome to reduce multicollinearity.A similar modeling approach was used to investigate the relationship between the separate SDM elements and adverse outcomes. We fit a multivariate model for adverse outcomes at follow-up using the individual elements of SDM and baseline adverse outcomes, after which we also tested for interactions between stage 1 (agenda setting) and 3 (exploration) and between stage 2 (information giving) and 3 (exploration). Again, both multivariate and univariate analyses were controlled for baseline differences and moderating variables.