Assessing Quality of Life, Economic Burden, and Independence Across the Alzheimer's Disease Continuum Using Patient-Caregiver Dyad Surveys

Abstract

Background: Alzheimer's disease (AD) and mild cognitive impairment (MCI) have negative quality of life (QoL) and economic impacts on patients and their caregivers and may increase along the disease continuum from MCI to mild, moderate, and severe AD.

Objective: To assess how patient and caregiver QoL, indirect and intangible costs are associated with MCI and AD severity.

Methods: An on-line survey of physician-identified patient-caregiver dyads living in the United States was conducted from June-October 2022 and included questions to both patients and their caregivers. Dementia Quality of Life Proxy, the Care-related Quality of Life, Work Productivity and Activity Impairment, and Dependence scale were incorporated into the survey. Regression analyses investigated the association between disease severity and QoL and cost outcomes with adjustment for baseline characteristics.

Results: One-hundred patient-caregiver dyads were assessed with the survey (MCI, n = 27; mild AD, n = 27; moderate AD, n = 25; severe AD, n = 21). Decreased QoL was found with worsening severity in patients (p < 0.01) and in unpaid (informal) caregivers (n = 79; p = 0.02). Dependence increased with disease severity (p < 0.01). Advanced disease severity was associated with higher costs to employers (p = 0.04), but not with indirect costs to caregivers. Patient and unpaid caregiver intangible costs increased with disease severity (p < 0.01). A significant trend of higher summed costs (indirect costs to caregivers, costs to employers, intangible costs to patients and caregivers) in more severe AD was observed (p < 0.01).

Conclusions: Patient QoL and functional independence and unpaid caregiver QoL decrease as AD severity increases. Intangible costs to patients and summed costs increase with disease severity and are highest in severe AD.

Keywords: Alzheimer’s disease; cost of illness; employer health costs; global burden of disease; health expenditure; indirect expenditure; intangible cost; mild cognitive impairment; quality of life.

Fig. 1

Survey methodology. ^aPatient questionnaire time ∼30 minutes; caregiver questionnaire time ∼45 minutes.

Fig. 2

Quality of life scores by AD disease severity: signficant interactions (A) Patient QoL measured by DEMQOL-Proxy (interaction between severity and patient marital status); (B) CarerQoL-7D utility among unpaid/informal caregivers (contour plot illustrating interaction between severity and caregiver age). AD, Alzheimer’s disease; DEMQOL, Dementia Quality of Life; CarerQoL-7D, Care-related Quality of Life –7 dimensions; MCI, mild cognitive impairment.

Fig. 3

Patient dependence by AD disease severity. (A) DS (overall finding); (B) DS (interaction between age and patient sex). AD, Alzheimer’s disease; DS, dependence scale; MCI, mild cognitive impairment.

Fig. 4

Costs by disease severity: significant interactions. (A) Indirect costs to caregivers (interaction between severity and caregiver marital status); (B) costs to employers (interaction between severity and caregiver marital status); (C) Intangible costs to unpaid/informal caregivers (contour plot illustrating interaction between severity and caregiver age); (D) Summed costs^a (interaction between severity and caregiver marital status). ^aSummed costs include the indirect costs to caregivers, costs to employers, and intangible costs to patients and caregivers. AD, Alzheimer’s disease; MCI, mild cognitive impairment.