OBJECTIVES: The National Institute for Health and Care Excellence (NICE) recommends modelling carer quality-of-life (QoL) if it is relevant to the decision problem; however, guidance on how to do this is lacking. The objective of this study was to identify methods used to quantify carer QoL in previous NICE submissions and, using an existing model, test the impact of these methods on cost-effectiveness results.

METHODS: A targeted literature review of published NICE appraisals identified three core methods for applying carer QoL data within HE models: absolute utilities, utility increments, and utility decrements. In addition to the core methods, caps and bereavement utilities were also identified. We implemented these methods in an existing Markov model evaluating a new treatment versus standard of care for a paediatric population. We assessed two key scenarios: with and without a treatment-specific mortality benefit for the new treatment. Results are presented as incremental net monetary benefit (iNMB), using a willingness-to-pay threshold of £30,000 per quality-adjusted life-year (QALY) gained.

RESULTS: Where there was no mortality difference, model results for each core method were equivalent. The most impactful results occurred in the scenario with a mortality difference. The absolute utility method demonstrated the greatest overall iNMB (£13,660), while the utility increment and decrement methods reduced the iNMB (-£43,947 and -£60,421, respectively). Bereavement utilities had a modest impact on results, and caps generally resulted in iNMB reductions for all methods.

CONCLUSIONS: The impact of the different core carer QoL methods becomes important only in situations where a mortality difference is modelled. The absolute utility approach introduces the greatest QALY benefit; however, its applicability and relevance should be considered. NICE guidance on methods to quantify carer QoL would be welcomed.