How redesigning AD clinical trials might increase study partners’ willingness to participate

Abstract

Timely recruiting and retaining participants into Alzheimer disease (AD) clinical trials is a challenge. We used conjoint analysis to identify how alterations in attributes of clinical trial design improve willingness to participate: risk, home visits, car service, or increased chance of receiving intervention. A total of 108 study partners of patients with very mild to severe stage AD rated willingness to allow their relative to participate in eight clinical trials that varied combinations of the four attributes. The highest utility was for home visits (0.89) which essentially compensated for the disutility of high risk (-0.85). The combination of home visits and car service was redundant, with almost no increase in utility over home visits alone. Seventeen percent were willing to participate in a trial with no amenities; the addition of home visits increased predicted willingness to participate to 27%; low risk, home visits, and higher chance of active treatment increased predicted willingness to 60%. The value of reducing the hassles of travel correlated well with measures of AD severity (activities of daily living r = 0.41, p < 0.001; basic activities of daily living r = 0.38, p < 0.001; Neuropsychiatric Inventory severity p = 0.24, p = 0.01; Neuropsychiatric Inventory distress r = 0.23, p < 0.02). No association was found between degree of study partner burden and willingness to tolerate risk of an intervention. Clinical trials that reduce travel inconvenience may offset the disincentive of study features such as the risk of intervention and may also increase willingness to participate. Redesigning trials may also help recruit patients with more severe Alzheimer disease. Shorter recruitment periods and increased retention rates may offset costs of these changes.