Economic Evaluation of Health Technologies in the Context of Ultra-Rare Diseases: A Rapid Scoping Review Protocol

Background: Ultra-rare diseases pose unique challenges for the economic evaluation of health technologies due to the scarcity of robust evidence, high uncertainty, and often elevated costs. Objective: To identify and characterize the economic modeling approaches used in the evaluation of health technologies in the context of ultra-rare diseases. Methods: This is a rapid scoping review that will be conducted in accordance with the Joanna Briggs Institute methodological guidance. Conceptual studies, methodological papers, and systematic reviews addressing models, methods, adaptations, and alternative proposals for economic evaluation in this context will be included. The search will be performed in major secondary databases, as well as sources of grey literature. The selection process will involve independent screening by pairs and cross-checking of exclusions. Data extraction will follow a pre-tested form. Results will be presented narratively, in tables, and graphically, describing the types of economic modeling identified, their methodological characteristics, and the main reported limitations. Expected Results: This synthesis is expected to help inform decision-makers, researchers, and health technology assessment agencies about more appropriate and transparent approaches for incorporating technologies targeting ultra-rare diseases. Conclusion: The findings may guide both researchers and policymakers on more appropriate strategies for incorporating technologies aimed at small and clinically complex populations, promoting practices that balance economic efficiency, equity, and sustainability of health systems.