Treatment effect expressed as the novel Delay of Event measure is associated with high willingness to initiate preventive treatment - A randomized survey experiment comparing effect measures.

OBJECTIVES This study aimed to investigate patients' willingness to initiate a preventive treatment and compared two established effect measures to the newly developed Delay of Events (DoE) measure that expresses treatment effect as a gain in event-free time. METHODS In this cross-sectional, randomized survey experiment in the general Swedish population,1079 respondents (response rate 60.9%) were asked to consider a preventive cardiovascular treatment. Respondents were randomly allocated to one of three effect descriptions: DoE, relative risk reduction (RRR), or absolute risk reduction (ARR). Univariate and multivariate analyses were performed investigating willingness to initiate treatment, views on treatment benefit, motivation and importance to adhere and willingness to pay for treatment. RESULTS Eighty-one percent were willing to take the medication when the effect was described as DoE, 83.0% when it was described as RRR and 62.8% when it was described as ARR. DoE and RRR was further associated with positive views on treatment benefit, motivation, importance to adhere and WTP. CONCLUSIONS Presenting treatment effect as DoE or RRR was associated with a high willingness to initiate treatment. PRACTICE IMPLICATIONS An approach based on the novel time-based measure DoE may be of value in clinical communication and shared decision making.