OBJECTIVES:

Caring for patients can impose significant ‘spillover effects’ on the health of informal carers. A review of National Institute for Health and Care Excellence technology appraisals found that carer health-related quality of life (HRQOL) is rarely included in appraisals, and when it is, modelling approaches have been inconsistent.

Furthermore, when modelling carer HRQOL, situations can occur whereby a life extension for patients results in an overall reduction in net quality-adjusted life years (QALYs). In other words, for some life-extending treatments, a gain in patient QALYs may be outweighed by a loss in carer QALYs, which may be inconsistent with societal values.

The objective of this study was to explore the circumstances through which this issue occurs and consider potential approaches for addressing it.

METHODS:

A literature review was conducted, after which a roundtable was organised with experts in economic modelling and the measurement/valuation of carer HRQOL. Consideration was given to the extent to which the issue is problematic, and the potential value of alternative modelling approaches and metrics (including consideration of bereavement effects).

RESULTS:

It was determined that this issue arises due to a variant of the classic ‘QALY trap’, whereby extending the life of a patient with a carer is less valuable than extending the life of a patient without a carer (if all else is equal) – denoted the ‘carer QALY trap’. Alternative modelling approaches could be used to minimise its impact, but these may be criticised due to the assumptions required. Alternative metrics may be useful for illustrating the issue but would represent a deviation from the standard QALY approach.

CONCLUSIONS:

Whilst alternative modelling approaches and metrics may ‘fix’ the issue, these require normative judgements. A better alternative may be to focus on assisting decision makers in identifying and understanding this issue when it arises to facilitate carefully considered deliberations.