The Humanistic and Economic Burden of Alzheimer's Disease.

Alzheimer's disease (AD) is the leading cause of cognitive impairment and dementia in older individuals (aged ≥ 65 years) throughout the world. As a result of these progressive deficits in cognitive, emotional, and physical function, AD dementia can cause functional disability and loss of independence. To gain a deeper understanding of the recent literature on the burden of AD, including that of mild cognitive impairment (MCI) due to AD, we conducted a comprehensive targeted review of the PubMed-indexed literature (2014 to 2021) to examine the humanistic and economic burden of AD (including MCI) in North America, Europe, and Asia. Our literature review identified a range of factors associated with quality of life (QoL): some factors were positively associated with QoL, including caregiver relationship, religiosity, social engagement, and ability to engage in activities of daily living (ADL), whereas other factors such as neuropsychiatric symptoms were associated with poorer QoL. While patient- and proxy-rated QoL are highly correlated in patients with early AD dementia, proxy-rated QoL declines more substantially as severity worsens. The maintenance of self-reported QoL in patients with more severe AD dementia may be due to lack of awareness or to adaptation to circumstances. Compared to persons with normal cognition, MCI is associated with a greater cost burden, and individuals with MCI exhibit worse QoL. Key drivers of the societal economic burden of AD include disease severity, dependence level, institutionalization, and comorbidity burden. Evaluation of the impact of a hypothetical disease-modifying treatment delaying the progression from MCI to AD has suggested that such a treatment may result in cost savings.