Spillover Effects on Caregivers’ and Family Members’ Utility: A Systematic Review of the Literature

Abstract

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.

Measuring Carer Outcomes in an Economic Evaluation: A Content Comparison of the Adult Social Care Outcomes Toolkit for Carers, Carer Experience Scale, and Care-Related Quality of Life Using Exploratory Factor Analysis

“…Although this focus is changing, a recent review indicated that studies that assessed spillover effects used the EQ-5D to measure caregiver/ family member utility, followed by other generic preferencebased measures, such as the Short Form Six Dimension or the Health Utilities Index. 8 With the development of carer-related preference-based measures, it is anticipated These are the variances of the items after accounting for all of the variance in the exploratory factor analysis model. that the use of these measures will increase in future economic evaluations, but the choice of measure is context dependent and requires careful considerations.…”

“…Yet, when conducting cost-effectiveness analyses, spillover effects are seldom measured, and there is variation in the measurement methods used. 8 To account for the impacts of health and social care interventions on informal care when conducting an economic evaluation, a number of carer-related preferencebased measures have been developed, which include the Care-Related Quality of Life (CarerQol), 9 the Carer Experience Scale (CES), 10 and the Adult Social Care Outcomes Toolkit for Carers (ASCOT-Carer). 11 Compared with other measures of carer burden or quality of life that often rely on simple sum scores, 12 these measures include a scoring algorithm that accounts for people's preferences, reflecting the fact that certain aspects of caring may be valued more than others.…”

Transforming discrete choice experiment latent scale values for EQ-5D-3L using the visual analogue scale

“…These include not wanting to be a burden on others, and not wanting to risk death due to responsibilities, for example as a carer [7]. There is growing interest in measuring health spillovers [50], especially for carers [51], so using VAS-based methods may be advantageous in these areas. Even if the VAS task is accepted as choice-based, an argument could be made that it is still not suitable for creating value sets for QALY calculation since it does not explicitly embody opportunity cost, as DCE TTO and hybrid methods do.…”

“…These include not wanting to be a burden on others, and not wanting to risk death due to responsibilities, for example as a carer [ 7 ]. There is growing interest in measuring health spillovers [ 50 ], especially for carers [ 51 ], so using VAS-based methods may be advantageous in these areas.…”

Evaluation Design of EFFICHRONIC: The Chronic Disease Self-Management Programme (CDSMP) Intervention for Citizens with a Low Socioeconomic Position

“…Likewise, the CDSMP intervention is expected to achieve great health gains and economic savings in caregivers, because they play a vital role in supporting citizens with a chronic condition. The association between the overall health of citizens with a chronic condition and the quality of life and perceived burden of their caregivers has been repeatedly confirmed [26]. Therefore, attention to the self-management of caregivers seems justified [27].…”