Communicating uncertainty can lead to less decision satisfaction: a necessary cost of involving patients in shared...

Given the large number of interventions of uncertain effectiveness, research on communicating uncertainty is needed to examine its impact on patients' health decisions.

To examine physicians' communication of uncertainty and its impact on patients' decisions and decision satisfaction.

Participants included female patients seen in a breast health centre whose physicians were discussing a decision with them, with no clear 'best' choice based on outcome evidence.

Decision communication was measured using the OPTION scale, a measure of the degree to which physicians involve patients in a decision-making process. One-to-two weeks after the discussion, patients reported their satisfaction with the decision-making process and their decision. Decisions were verified in medical charts with patient consent.

Seventy-five women agreed to participate (94% response rate). The mean translated score of the OPTION scale was 68.0 (SD 18.3), but only 33.2 (SD 19.1) for the uncertainty items. Among cancer patients, communicating uncertainty was negatively related to decision satisfaction (P < 0.002), and there was an interaction between patient involvement in decisions and communicating uncertainty in relation to patients' decision satisfaction (P < 0.03).

Communicating scientific uncertainty might lead to less decision satisfaction among women facing cancer treatment decisions; this could be a natural outcome of the decision making process. Involving patients in decisions might help them tolerate uncertainty.

Future studies should consider assessing other outcomes (e.g. knowledge, physician support) of the decision making process. There may be trade-offs between acknowledging uncertainty and immediate decision satisfaction.