Preferences about Future Alzheimer’s Disease Treatments Elicited through an Online Survey Using the Threshold Technique

Abstract

Treatments aiming at slowing down the progression of Alzheimer’s disease (AD) may soon become available. However, information about the risks that people are willing to accept in order to delay the progression of the disease is limited. To determine the trade-offs that individuals are willing to make between the benefits and risks of hypothetical treatments for AD, and the extent to which these trade-offs depend on individuals’ characteristics and beliefs about medicines. Online, cross-sectional survey study. Population in the UK. Public link to the survey available at the websites of Alzheimer’s Research UK and Join Dementia Research. Everyone self-reported ≥18 years old was eligible to participate. A total of 4384 people entered the survey and 3658 completed it. The maximum acceptable risks (MARs) of participants for moderate and severe adverse events in exchange for a 2-year delay in disease progression. The risks were expressed on ordinal scales, from <10% to ≥50%, above a pre-existing risk of 30% for moderate adverse events and 10% for severe adverse events. We obtained the population median MARs using log-normal survival models and quantified the effects of individuals’ characteristics and beliefs about medicines in terms of acceleration factors. For the moderate adverse events, 26% of the participants had a MAR ≥50%, followed by 25% of the participants with a MAR of 10 to <20%, giving an estimated median MAR of 25.4% (95% confidence interval [CI] 24.5 to 26.3). For the severe adverse events, 43% of the participants had a MAR <10%, followed by 25% of the participants with a MAR of 10 to <20%, resulting in an estimated median MAR of 12.1% (95%CI 11.6 to 12.5). Factors that were associated with the individuals’ MARs for one or both adverse events were age, gender, educational level, living alone, and beliefs about medicines. Whether or not individuals were living with memory problems or had experience as a caregiver had no effect on the MARs for any of the adverse events. Trade-offs between benefits and risks of AD treatments are heterogeneous and influenced by individuals’ characteristics and beliefs about medicines. This heterogeneity should be acknowledged during the medicinal product decision-making in order to fulfil the needs of the various subpopulations.