Background A growing body of research has identified health-related quality-of-life effects for caregivers and family members of ill patients (i.e. 'spillover effects'), yet these are rarely considered in cost-effectiveness analyses (CEAs). Objective The objective of this study was to catalog spillover-related health utilities to facilitate their consideration in CEAs. Methods We systematically reviewed the medical and economic literatures (MEDLINE, EMBASE, and EconLit, from inception through 3 April 2018) to identify articles that reported preference-based measures of spillover effects. We used keywords for utility measures combined with caregivers, family members, and burden. Results Of 3695 articles identified, 80 remained after screening: 8 (10%) reported spillover utility per se, as utility or disutility (i.e. utility loss); 25 (30%) reported a comparison group, either population values (n = 9) or matched, non-caregiver/ family member or unaffected individuals' utilities (n = 16; 3 reported both spillover and a comparison group); and 50 (63%) reported caregiver/family member utilities only. Alzheimer's disease/dementia was the most commonly studied disease/ condition, and the EQ-5D was the most commonly used measurement instrument. Conclusions This comprehensive catalog of utilities showcases the spectrum of diseases and conditions for which caregiver and family members' spillover effects have been measured, and the variation in measurement methods used. In general, utilities indicated a loss in quality of life associated with being a caregiver or family member of an ill relative. Most studies reported caregiver/family member utility without any comparator, limiting the ability to infer spillover effects. Nevertheless, these values provide a starting point for considering spillover effects in the context of CEA, opening the door for more comprehensive analyses.
Key PointsInclusion of caregiver and family member ('spillover') quality-adjusted life-years (QALYs) in cost-effectiveness analyses (CEAs) is recommended by multiple national guidance bodies.Caregiver and family member QALYs can include spillover utilities (the independent utility loss due to a family member's illness) that are rarely reported in the literature; more common are caregivers'/family members' utilities, sometimes in combination with a comparator utility.Research gaps remain in spillover effect estimation and incorporation methods, slowing the adoption of these additional measures of burden into cost-effectiveness evaluations.