Spillover Effect in Health Utility Values: A Systematic Review
Author(s)
Shitong Xie, PhD1, Jialu Geng, MSc2, Yvyang Zhang, MSc2.
1PhD, School of Pharmaceutical Science and Technology, Faculty of Medicine, Tianjin University, Tianjin, China, 2School of Pharmaceutical Science and Technology, Faculty of Medicine, Tianjin University, Tianjin, China.
1PhD, School of Pharmaceutical Science and Technology, Faculty of Medicine, Tianjin University, Tianjin, China, 2School of Pharmaceutical Science and Technology, Faculty of Medicine, Tianjin University, Tianjin, China.
OBJECTIVES: To systematically identify studies that report spillover effects quantified via health utility values, focusing on both absolute and relative utility changes, to facilitate their inclusion in Cost-Utility Analysis (CUA).
METHODS: A systematic literature search was conducted in MEDLINE, Embase, PsycINFO, and Econ-Lit from inception to January 2025. Data extraction included study characteristics, affected populations, measurement methods, and spillover effects outcomes. Studies were categorized by absolute or relative spillover effects and analyzed thematically. Absolute spillover effects refer to the utility difference between individuals exposed to a patient’s condition (e.g., caregivers) and those unexposed. Relative spillover effects describe changes in the caregiver's utility that correlate with changes in the patient's health status.
RESULTS: Twelve studies published between 2013 and 2024 were included, mainly from the U.S. and U.K. Most assessed spillovers among family members or caregivers of patients with mental illness, chronic conditions, or care needs. Absolute spillover effects about poor patient health ranged from -0.26 to -0.04. Two studies measured absolute spillover effects associated with patient interventions: one reported a positive effect ranging from 0 to 0.019, while the other found a negative effect of -0.007 (but not significant). Relative spillover effects were estimated through regression models linking changes in the patient’s health status to utility shifts in caregivers/family members. The spillover effect coefficients from the utility of patients to that of caregivers/family members ranged from 0.056 to 0.30.
CONCLUSIONS: This review systematically classified spillover effects across diverse health and caregiving contexts and summarized two main measurement approaches. Most identified spillover effects were small but negative, which supports the inclusion of spillover effects in future CUAs, particularly where they improve the accuracy and relevance of economic evaluations.
METHODS: A systematic literature search was conducted in MEDLINE, Embase, PsycINFO, and Econ-Lit from inception to January 2025. Data extraction included study characteristics, affected populations, measurement methods, and spillover effects outcomes. Studies were categorized by absolute or relative spillover effects and analyzed thematically. Absolute spillover effects refer to the utility difference between individuals exposed to a patient’s condition (e.g., caregivers) and those unexposed. Relative spillover effects describe changes in the caregiver's utility that correlate with changes in the patient's health status.
RESULTS: Twelve studies published between 2013 and 2024 were included, mainly from the U.S. and U.K. Most assessed spillovers among family members or caregivers of patients with mental illness, chronic conditions, or care needs. Absolute spillover effects about poor patient health ranged from -0.26 to -0.04. Two studies measured absolute spillover effects associated with patient interventions: one reported a positive effect ranging from 0 to 0.019, while the other found a negative effect of -0.007 (but not significant). Relative spillover effects were estimated through regression models linking changes in the patient’s health status to utility shifts in caregivers/family members. The spillover effect coefficients from the utility of patients to that of caregivers/family members ranged from 0.056 to 0.30.
CONCLUSIONS: This review systematically classified spillover effects across diverse health and caregiving contexts and summarized two main measurement approaches. Most identified spillover effects were small but negative, which supports the inclusion of spillover effects in future CUAs, particularly where they improve the accuracy and relevance of economic evaluations.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
EE669
Topic
Economic Evaluation, Health Technology Assessment, Patient-Centered Research
Topic Subcategory
Novel & Social Elements of Value
Disease
No Additional Disease & Conditions/Specialized Treatment Areas