Dobra RA, Boeri M, Elborn S, Kee F, Madge S, Davies JC. Discrete choice experiment (DCE) to quantify the influence of trial features on the decision to participate in cystic fibrosis (CF) clinical trials. BMJ Open. 2021 Mar 2;11(3):e045803.

INTRODUCTION: Engaging people with cystic fibrosis (CF) in clinical trials is critical to improving outcomes for this fatal disease. Following extensive exploration of engagement in CF trials we believe 6 key questions remain: • Does the type of medicine being investigated influence willingness to participate? • Are patients prepared to attend trial visits at a site different from their clinical centre, and how far will they travel? • Does stipend provision influence the decision to participate, and what is the optimum stipend? • Are drug washout periods acceptable to patients? • Are placebo-controlled trials acceptable to patients? • Does the mechanism of accessing the medicine after the trial is finished influence the decision to participate, and what are the preferred access methods?

We have designed and will administer an online discrete choice experiment (DCE) to elicit and quantify preferences of people with CF for these trials’ attributes and estimate the relative importance of an attribute when choosing to participate in a trial. The cross-sectional data generated will be explored using conditional multinomial logit (MNL) model. Mixed logit models such as the random-parameters logit (RPL) and a Latent class (LC) models will be utilized to explore preference heterogeneity. To determine the relative importance of an attribute, the difference between the attribute level with the highest preference weight and the level with the lowest preference weight will be calculated.

ETHICS AND DISSEMINATION: Imperial College London Joint Research Compliance Office has granted ethical approval for this low risk study. Patient consent will be sought following full explanation. No identifying information will be collected. Dissemination will be via international conferences, peer review publication and patient accessible forums. Major CF trials networks have agreed to incorporate our findings into their review process, meaning our results can realistically influence and optimise CF trial delivery.

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