What are we trying to prevent in Alzheimer disease?

Within aging societies, the number of individuals suffering from Alzheimer disease (AD) is constistently increasing. This is paralleled by intense research aimed at improving treatment options and potentially even fostering effective prevention. The discussion on relevant outcomes of such interventions is ongoing. Here, different types of currently applied outcomes in the treatment of AD at the dementia stage, but also at the pre-dementia stages of mild cognitive impairment (MCI) and asymptomatic preclinical AD are discussed. Regulatory agencies require effects on the clinical measures of cognition and function. In novel disease-modifying therapy trials, biological markers are used as secondary and exploratory outcomes. Additional outcomes of great relevance for the individual patients are neuropsychiatric symptoms, quality of life, and goal attainment. In addition, costs and cost-benefit ratios are of interest for the reimbursement of interventions.