Can We Mitigate the Caregiver QALY Trap in Economic Evaluations? A Case Study in Duchenne Muscular Dystrophy

OBJECTIVES: Incorporating caregiver burden for treatments that also extends life can have a negative impact on the incremental cost-effectiveness ratio. This arises for treatments that prolong survival in diseases with significant informal care demands, thereby accruing losses in caregiver utilities (stemming from the provision of informal care) during the life-years gained with a high caregiver burden. In this scenario, strictly maximizing QALYs introduces a trade-off between extending the life of the patient and reducing the burden of the caregiver, a phenomenon referred to as the “caregiver QALY trap”. The objective of this case study was to explore the impact of bereavement health effects to offset the caregiver QALY trap in Duchenne muscular dystrophy (DMD), a rare, severely debilitating, and ultimately fatal neuromuscular disease characterized by progressive muscle wasting and serious multi-system complications.

METHODS: We developed a partitioned survival model replicating the health states and standard of care (SOC) efficacy from the DMD model by the Institute for Clinical and Economic Review. A hypothetical intervention was modelled with a hazard ratio vs. SOC of 0.38 for all endpoints representing the treatment effect; this delayed median age at loss of ambulation by five years. Different methods of incorporating a bereavement effect were explored, including an initial disutility followed by a gradual return to general population utility or a lower baseline; a one-off QALY loss; and caregiver treatment-specific utilities to capture differences in subsequent expected bereavement.

RESULTS: Without a bereavement effect, the QALY trap resulted in a lifetime caregiver incremental QALY loss of 0.12. All explored methods were able to offset the trap using relatively conservative assumptions.

CONCLUSIONS: We show that the incorporation of a bereavement effect can successfully mitigate the caregiver QALY trap in DMD. Further research into the health effects of bereavement is warranted.