Economic Evaluation in Duchenne Muscular Dystrophy: Model Frameworks for Cost-Effectiveness Analysis

BACKGROUND: Several treatments are on the horizon for Duchenne muscular dystrophy (DMD), a terminal orphan disease. In many jurisdictions, decisions regarding pricing and reimbursement of these health technologies comprise evidence of value for money. OBJECTIVE: The objective of this study was to develop a cost-effectiveness model based on the Duchenne muscular dystrophy Functional Ability Self-Assessment Tool (DMDSAT), a new rating scale created specifically to measure disease progression in clinical practice and trials and model DMD in economic evaluations, and compare it with two alternative model structures. METHODS: We constructed three Markov cohort state-transition models to evaluate the cost-effectiveness of a hypothetical intervention for DMD versus standard of care in a UK setting. Model I was based on the DMDSAT, model II on stages of disease as defined in the DMD clinical care guidelines and model III on patients' ventilation status. The conceptual model structures were formulated in collaboration with three DMD experts. RESULTS: All three models were judged to have good validity with regards to the appropriateness of the choice of modelling technique, conceptual representation of the disease, model input data and model outcomes. Across frameworks, lifetime direct medical costs with standard of care ranged between £217,510 and £284,640, total costs between £624,240 and £713,840, and total number of quality-adjusted life-years between 5.96 and 7.17. CONCLUSIONS: We present a first version of a model for the economic evaluation of treatments for DMD based on the DMDSAT, as well as two alternative frameworks encompassing conventional staging of disease progression. Our findings should be helpful to inform health technology assessments and health economic programmes of future treatments for DMD.