Understanding Patient Preferences in Medication Nonadherence: A Review of Stated Preference Data.

Nonadherence is a global problem undermining the cost-effectiveness of evidence-based medications. Aligning treatment choices with patient preferences may promote adherent behaviour: eliciting patient treatment preferences may help resolve the problem of nonadherence. As there is no reliable measure of nonadherent behaviour that can be used to derive preferences, stated-preference techniques offer a robust alternative. To understand patient preferences in medication nonadherence, we systematically appraised full-text English studies (from database inception to 24 February 2014) involving participants evaluating hypothetical scenarios to elicit preferences as an explicit means to understand medication nonadherence. Study characteristics (e.g. setting, disease, stated-preference method), attribute type and influence on choice were extracted. Seventeen full-text articles (4,456 patients) were included in the review, which reports stated-preference elicitation studies across a wide range of chronic and acute conditions. All studies were conducted in high-income settings. The influence of drug-related factors was predominant in patients' preferences for treatment. Patients preferred efficacious over safe medications except when considering the duration of therapy, but dosing and cost appeared more important when contemplating adherence. Patient characteristics, particularly medication experience, significantly influenced preferences. A disparity between stated preferences for treatment and adherence was reported. When using stated-preference techniques to understand nonadherence, this manuscript highlights that there is much room for methodological development. Studies outside of high-income settings are needed, particularly in relation to chronic diseases, for which nonadherence poses a substantial economic burden to health systems and patients. To inform the problem of sustaining adherence, prospective research is needed to understand how preferences change with time. The usefulness of stated-preference techniques to inform policy and practice requires a better understanding of how stated preferences relate to actual adherence behaviour.