Background: Given the broad scope of the spillover effects of illness, it is important to characterize the variability in these outcomes to identify relationship types in which secondary impacts of illness are particularly important to include in health economic evaluations.
Purpose: To examine heterogeneity in spillover effects of chronic conditions on family members by type of familial relationship with patient.
Methods: Adults (aged ≥18 years) and adolescents (aged 13-17 years) who had a parent, spouse, or child in their household with a chronic condition (Alzheimer's disease/dementia, arthritis, cancer, or depression) were recruited from a US national panel to participate in an on-line survey. Respondents were asked to rate the spillover effect of their family member's illness on their own health on a 0-100 scale, with lower scores indicating greater spillover. Regression analysis was used to evaluate the association between rating scale scores and relationship with an ill family member (ill parent, child, or spouse) for each illness separately, controlling for caregiving responsibility and the health status of the ill family member.
Results: 1,267 adults and 102 adolescents met inclusion criteria. In adjusted analyses, having a sick child was significantly (p < 0.05) associated with lower rating scale scores compared with having a spouse with the same condition (cancer: -24.2; depression -9.7). Having a non-elderly or elderly adult parent with a condition, compared with a spouse, was significantly associated with lower rating scale scores for arthritis (-3.8) and depression (-5.3), but not for Alzheimer's disease/dementia or cancer.
Conclusions: The impact of illness on family members, measured with a rating scale, varies by relationship type for certain illnesses. Having a child with cancer, a parent with arthritis, or either with depression, is significantly associated with greater spillover, compared with having a spouse with one of these conditions.