Preferences of patients and pharmacists with regard to the management of drug-drug interactions: A choice-based conjoint analysis

Background For the management of drug-drug interactions (DDI), a risk-benefit assessment should be combined with the patient's perspective. Objective To investigate patients' and pharmacists' preferences regarding DDI management Design and methods We conducted an online choice-based conjoint survey among patients and pharmacists. The choice task was about the management of a fictitious DDI: the combination of a cardiovascular drug and an antibiotic for pneumonia leading to a risk for developing muscle problems. Respondents answered twelve choice sets of two DDI-management options. The options were only described by their five characteristics (attributes) regarding risk for adverse events, benefit, and practical consequences. Each of the five attributes could have two different levels (e.g. low or high risk), which were varied over the 12 choice tasks. Data were analysed by latent class analysis in order to identify potential classes (subgroups) of respondents with similar preference patterns. Results The survey was completed by 298 patients and 178 pharmacists. The latent class model for both patients and pharmacists resulted in three classes. The first class of patients attached most importance to fewer adverse events (class probability 41%), the second class attached most importance to avoiding a medication switch (20%), and the third class attached most importance to blood sampling (39%). For pharmacists, the first class attached most importance to curing pneumonia (31%), the second class to avoiding a medication switch (31%), and the third class to avoiding blood sampling (38%). Conclusion Among patients and pharmacists diverging preferences regarding DDI management were observed. Some subgroups of respondents attached most value to risk or benefit while others attached more value to practical considerations. Awareness of existing variability in preferences among and between pharmacists and patients can contribute to shared decision making in DDI management