Presentation (CTI)

OBJECTIVES: Pennington et al. (2026) proposed a novel framework for modelling caregiver health-related quality of life (HRQoL), introducing a conceptual framework in which caregiver spillovers are represented by distinct family and caregiving effects. The approach provides a more nuanced representation of caregiver spillovers than previous one-dimensional methods, allowing for incorporation of both positive and negative impacts of caregiving. We examined the mathematical formulation of the proposed method and its implications for estimating caregiver HRQoL.
METHODS: The conceptual framework proposed by Pennington et al. was expressed as a mathematical equation based on the steps outlined in the paper. The resulting formulation was then appraised to ensure reproduction of results in the worked example provided in the publication. The implications of the approach for estimating caregiver HRQoL were also subsequently assessed.
RESULTS: Appraisal of the resulting mathematical formulation indicated that the derived equation could be streamlined due to cancellation of patient health-state utility-related terms, such that the formula simplifies to: Total caregiver HRQoL = (Baseline patient utility × Family effect multiplier) - Caregiver disutility, where baseline patient utility represents the expected utility in the absence of disease. Consequently, the total caregiver HRQoL is determined independently of changes in the patient's current health-state utility (improvement or deterioration), with caregiver HRQoL actually modelled as a function of expected patient baseline utility. Applying the simplified equation reproduced the caregiver HRQoL estimates reported in the published worked example.
CONCLUSIONS: The proposed family and caregiving framework represents an important conceptual advance by recognising distinct family and caregiving spillover effects. However, the mathematical formulation appears to simplify in a way that removes the influence of patient health-state utility on caregiver HRQoL, and where the “family effect” term cancels out with part of the “caregiving effect” terms. Further methodological refinement may therefore be warranted to ensure the implementation reflects the intended conceptual framework.