Discriminatory Properties of Quality-Adjusted Life Year Based Cost-Effectiveness Analyses for Patients With Disabilities: A Duchenne Muscular Dystrophy Case Study.

Objectives: Quality-adjusted life years (QALYs) have been challenged as a measure of benefit for people with disabilities, particularly for those in low-utility health states or with irreversible disability. This study examined the impact of a QALY-based assessment on the price for a hypothetical treatment for Duchenne muscular dystrophy (DMD), a progressive, genetic neuromuscular disease.

Methods: A previously published, 5-state model, which analyzed treatments for early ambulatory (EA) DMD patients, was replicated, validated, and adapted to include early nonambulatory (ENA) DMD patients. The model was used to assess a QALY-based threshold price (maximum cost-effective price) for a hypothetical treatment for 13-year-old ENA and 5-year-old EA patients (initial health states with lower and higher utility, respectively). All inputs were replicated including willingness-to-pay thresholds of $50 000 to $200 000/QALY.

Results: In contrast to EA patients, ENA patients had a 98% modeled decline in QALY-based threshold price at a willingness-to-pay of $150 000/QALY or higher, despite equal treatment benefit (delayed progression/death). At $100 000/QALY or lower, net nontreatment costs exceeded health benefits, implying any treatment for ENA patients would not be considered cost-effective, even at $0 price, including an indefinite pause in disease progression.

Conclusions: For certain severe, disabling conditions, traditional approaches are likely to conclude that treatments are not cost-effective at any price once a patient progresses to a disabled health state with low utility value. These findings elucidate theoretical/ethical concerns regarding potential discriminatory properties of traditional QALY assessments for people with disabilities, particularly those who have lost ambulation or have other physical limitations.