Purpose: To measure the spillover effects on HRQOL of having a family member with a chronic illness using direct health utility assessment methods.
Method: Using a national sample of US adults, we conducted two cross-sectional surveys in December 2011-January 2012: one version that asked respondents to value hypothetical health states describing the experience of having a family member with a chronic illness (community sample) and one version that asked respondents to value their own experience as the family member of a person with a chronic illness (experienced sample). Chronic illnesses in the survey included Alzheimer’s disease/dementia, arthritis, cancer, cerebral palsy, and depression. Specific illness included in each survey depended on the age of the hypothetical ill individual (child, adult, senior). Respondents for the experienced sample were identified as having a household member with one of these conditions. Using standard gamble questions, respondents were asked to value the spillover effects of a family member’s illness for either hypothetical vignettes or for their own experience as a family member of an ill individual. Disutility is defined as the loss in utility. We used regression analysis to evaluate the disutility associated with having a family member with a chronic illness varied by condition or type of relationship controlling for respondent’s own conditions and sociodemographic characteristics. For the community sample, we also adjusted for multiple observations per respondent.
Result: For the community sample (n=1205), median (95th % CI) spillover disutilities ranged from 0.15 (0.12, 0.25) for cerebral palsy to 0.20 (0.17, 0.26) for cancer. Regression analyses indicated that higher spillover disutility was associated with type of relationship (spouse), lower socioeconomic status, and caregiver experience for the community sample. For the experienced sample (n=1389), median spillover disutilities ranged from 0.06 (0.001, 0.51) for cerebral palsy to 0.27 (0.12, 0.39) for cancer. Regression analyses also suggested higher spillover disutility was associated with lower socioeconomic status but not with type of relationship for the experienced sample.
Conclusion: The effects of illness extend beyond the individual patient to include effects on caregivers of patients, parents of ill children, spouses, and other close family and household members. Cost-effectiveness analyses should consider the inclusion of HRQOL spillover effects in addition to caregiving time costs incurred by family members of ill individuals.