A health state utility valuation study to assess the impact of treatment mode of administration in Gaucher disease

The estimation of health state utility values in rare diseases: do the approaches in submissions for NICE technology appraisals reflect the existing literature? A scoping review

BACKGROUND

Rare diseases negatively impact patients' quality of life, but the estimation of health state utility values (HSUVs) in research studies and cost-utility models for health technology assessment is challenging.

OBJECTIVES

This study compared the methods for estimating the HSUVs included in manufacturers' submissions of orphan drugs to the National Institute for Health and Care Excellence (NICE) with those of published studies addressing the same rare diseases to understand whether manufacturers fully exploited the existing literature in developing their economic models.

METHODS

All NICE Technology Appraisal (TA) and Highly Specialized Technologies (HST) guidance documents of non-cancer European Medicines Agency (EMA) orphan medicinal products were reviewed and compared with any published primary studies, retrieved via PubMed until November 2020, and estimating HSUVs for the same conditions addressed in manufacturers' submissions.

RESULTS

We identified 22 NICE TA/HST appraisal reports addressing 19 different rare diseases. Sixteen reports presented original HSUVs estimated using EQ-5D or Health Utility Index (n = 12), direct methods (n = 2) or mapping (n = 2), while the other six included values obtained from the literature only. In parallel, we identified 111 published studies: 86.6% used preference-based measures (mainly EQ-5D, 60.7%), 12.5% direct techniques, and 2.7% mapping. The collection of values from non-patient populations (using 'vignettes') was more frequent in manufacturers' submissions than in the literature (22.7% vs. 8.0%).

CONCLUSIONS

The agreement on methodological choices between manufacturers' submissions and published literature was only partial. More efforts should be made by manufacturers to accurately reflect the academic literature and its methodological recommendations in orphan drugs submissions.

Vignette-Based Utilities: Usefulness, Limitations, and Methodological Recommendations

Health technology assessment agencies often prefer that utilities used to calculate quality-adjusted life years in cost-utility analyses (CUAs) are derived using standardized methods, such as generic preference-based measures completed by patients in clinical trials. However, there are situations when no standardized approach is feasible or appropriate for a specific medical condition or treatment that must be represented in a CUA. When this occurs, vignette-based methods are often used to estimate utilities. A vignette (sometimes called a "scenario," "health state description," "health state vignette," or "health state") is a description of a health state that is valued in a preference elicitation task to obtain a utility estimate. This method is sometimes the only feasible way to estimate utilities representing a concept that is important for a CUA. Consequently, vignette-based studies continue to be conducted and published, with the resulting utilities used in economic models to inform decision making about healthcare resource allocation. Despite the potential impact of vignette-based utilities on medical decision making, there is no published guidance or review of this methodology. This article provides recommendations for researchers, health technology assessment reviewers, and policymakers who may be deciding whether to use vignette-based methods, designing a vignette study, using vignette-based utilities in a CUA, or evaluating a CUA that includes vignette-based utilities. Recommendations are provided on: (A) when to use vignette-based utilities, (B) methods for developing vignettes, (C) valuing vignettes, (D) use of vignette-based utilities in models, and (E) limitations of vignette methods.

Increasing respondent engagement in composite time trade-off tasks by imposing three minimum trade-offs to improve data quality

BACKGROUND

Web-based surveys are increasingly utilized for health valuation studies but may be more prone to lack of engagement and, therefore, poor data validity. The objective of this study was to evaluate the effect of imposed engagement (i.e., at least three trade-offs) in the composite time trade-off (cTTO) task.

METHODS

The EQ-5D-5L valuation study protocol and study design were adapted for online, unsupervised completion in two arms: base case and engagement. Validity of preferences was assessed using the prevalence of inconsistent valuations and expected patterns of TTO values. Respondent task engagement was measured using time per task. Value sets were generated using linear regression with a random intercept (RILR).

RESULTS

The base case (n = 501) and engagement arms (n = 504) clustered at different TTO values: [base case] 0, 1; [engagement] -0.5, 0.45, 0.6. Mean TTO values were lower for the engagement arm. Engagement respondents did not spend more time per TTO task: [base case] 63.3 s (SD 77.9 s); [engagement] 64.7 s (SD 73.3 s); p = 0.36. No significant difference was found between arms for prevalence of respondents with at least one inconsistent TTO value: [base case] 61.1%; [engagement] 63.5%; p = 0.43. Both value sets had significant intercepts far from 1: [base case] 0.846; [engagement] 0.783. The relative importance of the EQ-5D dimensions also differed between arms.

CONCLUSIONS

Both online arms had poor quality data. A minimum trade-off threshold did not improve engagement nor face validity of the data, indicating that modifications to the number of iterations are insufficient alone to improve data quality/validity of online TTO studies.

A patient with Gaucher disease and plasma cell dyscrasia: bidirectional impact

Patients with Gaucher disease (GD), a rare autosomal recessive glycosphingolipid storage disease, commonly present to hematologists with unexplained splenomegaly, thrombocytopenia, anemia, and bone symptoms. Patients with GD may develop other manifestations, such as autoimmune thrombocytopenia, monoclonal gammopathy, multiple myeloma, or, even more rarely, other hematological malignancies; sometimes they are first diagnosed during an assessment of those disorders. Although the diagnosis and management of patients with GD have significantly evolved over the last 30 years, some patients remain poor responders to GD-specific therapy, needing novel and investigational therapies. Ideally, patients with GD, like patients with other rare diseases, should be managed by a multidisciplinary team expert with the diverse clinical manifestations and potential GD-related or -unrelated comorbidities. The hematology community should be knowledgeable regarding the presentation and the variety of hematologic complications and comorbidities associated with Gaucher disease.