Can Carer Quality Adjusted Life Year (QALY) Shortfall Help US Quantify the Caregiving Burden in Health Technology Assessment (HTA)? Learnings From a Case Study in Amyotrophic Lateral Sclerosis (ALS)

OBJECTIVES: QALY shortfall can be used by HTA bodies to give additional weighting to interventions for the most severe conditions, but guidance specifies that QALY shortfall calculations should exclude carers. Recommendations on how carer HRQoL should be included in economic evaluation are minimal, and there are methodological and normative issues with modelling carer QALYs. We aimed to explore the feasibility of calculating carer QALY shortfall and how it might impact HTA decision-making.

METHODS: We built a Markov model comparing edaravone and standard of care (SoC) in ALS from a UK NHS perspective. Health states were based on the King’s clinical staging system, with transitions, patient utilities, and carer disutilities from previous evaluations in ALS. We calculated patient and carer QALY shortfall for SoC and used the NICE severity thresholds and weights.

RESULTS: Patient absolute QALY shortfall (AQS) was 9.60 and proportional QALY shortfall (PQS) was 0.879. Carer AQS was 0.308 over the patient’s lifetime or 0.448 over the carer’s lifetime (including bereavement). The carer PQS was 0.102 over the patient’s lifetime or 0.041 over the carer’s lifetime. The patient QALY shortfall met the threshold for a 1.2x QALY weighting, but carer QALY shortfall alone, or combined patient and QALY shortfall, did not. In all scenario analyses, carer QALY shortfall was smaller than patient QALY shortfall. Carer AQS was greater over the carer’s lifetime, and carer PQS was greater using the patient’s lifetime. Raising the carer’s age increased AQS but decreased the PQS. Including multiple carers increased the AQS.

CONCLUSIONS: Carer QALY shortfall is straightforward to calculate from carer disutilities, but decisions need to be made regarding: whether patient and carer QALY shortfall can be combined, if the patient or carer’s lifetime should be considered, and whether carer QALY shortfall should use the same thresholds and weights as patient QALY shortfall.