Introduction In primary care, patients are faced with the choice of whether or not to take an optional prescription drug. DECIdE aims to develop a decision aid exposing the benefit-risk balance of these drugs to help general practitioners (GP) or community pharmacist (CP) to practice shared-decision making (SDM).

Methods Following a user-centred design approach, DECIdE was developed in three stages.

A set of specifications was drawn up by consensus of a nominal group of patients, GPs and CPs.The first prototype was user tested by GPs and pharmacists with their patients in simulated SDM situations. The thematic analysis of the open individual interviews conducted by clinical psychologists permitted to improve the prototype. An ethic committee approved this study.Finally, an expert consensus by the eDELPHI method was sought to validate DECIdE as a decision aid.

Results The nominal group (4 patients, 6 GPs and 6 CPs) agreed on several criteria about the presentation of symptoms, molecules and benefit/risk balance and level of evidence.

2 cycles of users-tests were performed. Analysis of 24 interviews permitted to improve the readability, enhance visual representation of the frequency of adverse effects, level of evidence and effectiveness on patient important outcomes. A social psychologist helped to erase cognitive bias.16 experts responded to the eDELPHI questionnaire. A consensus was reached after the first round on 10 of the 13 proposals directly inspired by the IPDAS criteria. A second round is currently taking place, after adjustments.

Discussion Following a rigorous three stages user-centered method, DECIdE met the challenge to be a decision aid adaptable to several molecules and situations.

Conclusion In 2024, DECIdE will be evaluated on its impact on the decision conflict scale by a randomised clinical trial in real life involving 48 GPs and CPs in France.