Presentation (CTI)

OBJECTIVES: Disease-specific reference case extensions have been proposed to complement standard health technology assessment (HTA) methods to improve consistency and efficiency across appraisals. We aimed to systematically evaluate methodological, structural, and implementation considerations associated with disease-specific reference case extensions, using the National Institute for Health and Care Excellence (NICE) obesity framework as a case study and develop a prioritization framework to inform future selection and operationalization of disease-specific extensions.
METHODS: A structured policy and methods analysis was undertaken of NICE guidance PMG50 and NICE technology appraisals informing the obesity framework to identify methodological precedents underpinning the guidance. Data extraction followed a predefined analytic framework covering: (i) Evidence synthesis and parameterization, (ii) Structural modeling assumptions, and (iii) Resource use, costing conventions, and system-level considerations.
RESULTS: NICE’s obesity reference case extension largely consolidates modeling approaches and assumptions that have been recurrent sources of methodological debate. However, key implementation challenges include: (1) Availability of data to meet parameterization requirements; (2) Governance arrangements for maintaining disease-specific guidance in rapidly-evolving disease areas; (3) Reliance on early service-delivery models; and (4) Uncertainty around appropriate selection of candidate disease areas where guidance can codify precedent rather than create it. Drawing on these findings, we propose the READI framework to guide prioritization of future reference case extensions [(R)epeated methodological disputes, (E)vidence availability under sponsor evidence constraints, (A)ppraisal volume, (D)istinct modeling paradigm and (I)mpact on public health]. While Metabolic dysfunction-Associated Steatohepatitis (MASH) has been raised as the next topic, applying READI suggests there may be other, more mature disease areas which represent stronger near-term candidates.
CONCLUSIONS: Disease-specific reference case extensions may improve transparency and consistency in HTA modelling, but risk institutionalizing inappropriate assumptions in rapidly evolving therapeutic areas. READI provides a pragmatic approach to target disease-specific guidance where it is most likely to improve decision quality.