(108) Evaluating Caregiver Quality of Life, Indirect and Intangible Costs and their Association with Alzheimer’s Disease Severity in the US

Background: Alzheimer’s disease (AD) is a chronic, progressive disease that currently affects an estimated 6.7 million people aged 65 years and older in the United States (US). Most of the support provided to people with dementia (70-75%) comes from family members, friends, or other unpaid (informal) caregivers.

Objectives: This study aimed to evaluate the association of caregiver quality of life (QoL), indirect and intangible costs to caregivers with disease severity among all caregivers, and a subgroup of informal caregivers only.

Methods: A survey was conducted among patient-caregiver pairs living in the US. Patients had to be diagnosed with MCI or AD by their treating physician, and caregivers had to provide care to the patient at least 3 months prior to the survey. Questions regarding employment/work productivity of caregivers were included. Care-related QoL for caregivers was assessed with the CarerQoL-7D instrument. Indirect costs to caregivers were defined as the costs for unpaid caregiving services and calculated using the opportunity cost method. Intangible costs to caregivers were defined as costs attributed to loss in QoL and calculated using the utility values derived from the CarerQoL-7D. The health utility value of the caregiver was subtracted from the age-standardized health utility value of general US population to derive the estimate of utility reduction due to the caregiving role. Intangible costs were calculated using the willingness-to-pay threshold of $150,000 for one quality-adjusted life year gained. Regression analyses were applied to investigate the association between disease severity and QoL and cost outcomes with adjustment for baseline characteristics. Subgroup analyses were performed among informal caregivers only.

Results: A total of 100 patient-caregiver pairs were analyzed with MCI (n=27) and mild (n=27), moderate (n=25), and severe (n=21) AD. Among all caregivers, 38% were aged < 50 years, 65% were female, and 57% were employed. A total of 79 unpaid/informal caregivers were included in the survey. Considering all caregivers (formal and informal), no significant associations of QoL or intangible costs with disease severity were observed. However, when assessed among informal caregivers only, intangible costs increased with disease severity (p < 0.01), and quality of life decreased with disease severity (p=0.02). As for indirect costs to caregivers (all, informal only), no significant relationship was observed with disease severity.

Conclusions: QoL decreased and intangible costs increased with increasing AD severity for informal caregivers only. When evaluating such associations, it is important to consider the type of caregiving (informal or formal).