Health state utility values (QALY weights) for Huntington's disease: an analysis of data from the European Huntington's Disease Network (EHDN)

Health state utility estimates for value assessments of novel treatments in Huntington's disease: a systematic literature review

BACKGROUND

Huntington's disease (HD) is a progressive neurodegenerative disease with a devastating impact on patients and their families. Quantifying how treatments affect patient outcomes is critical for informing reimbursement decisions. Many countries mandate a formal value assessment in which the treatment benefit is measured as quality-adjusted life-years, calculated with the use of utility estimates that reflect respondents' preferences for health states.

OBJECTIVE

To summarize published health state utility data in HD and identify gaps and uncertainties in the data available that could be used to inform value assessments.

METHODS

We conducted a systematic literature review of studies that used preference-based instruments (e.g., EQ-5D and SF-6D) to estimate utility values for people with HD. The studies were published between January 2012 and December 2022.

RESULTS

Of 383 articles screened, 16 articles reported utility values estimated in 11 distinct studies. The utility measure most frequently reported was EQ-5D (9/11 studies). Two studies reported SF-6D data; one used time trade-off methods to value health state descriptions (vignettes). Although utility scores generally worsened to a lower value with increased HD severity, the estimates varied considerably across studies. The EQ-5D index range was 0.89 - 0.72 for mild/prodromal HD and 0.71 - 0.37 for severe/late-stage disease.

CONCLUSIONS

This study uncovered high variability in published utility estimates, indicating substantial uncertainty in existing data. Further research is needed to better understand preferences and valuation across all stages and domains of HD symptoms and the degree to which generic utility measures capture the impact of cognitive changes on quality of life.

Health related quality of life, service utilization and costs for patients with Huntington's disease in Norway

BACKGROUND

Huntington's disease (HD) is a progressive genetic neurodegenerative disease accompanied by mental and neurocognitive disabilities, which requires long-term and comprehensive treatment and care. Information on the health and economic burden of HD is scarce, but essential for conducting health economic analyses, in light of the prospect of new therapies for HD. In this study, we aim to identify values for Health-Related Quality of Life (HRQoL), describe service utilization and costs, and their associations with clinical and socio-demographic variables across all phases of HD.

METHODS

A cross-sectional study including 86 patients across all phases of HD. Values of HRQoL were calculated based on EQ-5D-3L index scores. Additionally, health care and societal costs were estimated based on service utilization collected using the Client Service Receipt Inventory (CSRI) and data from the patients' interviews. Total societal costs included costs of primary and secondary health care services, informal care and productivity loss of the patients. Multiple regression analyses were used to investigate associations between socio-demographic and clinical variables on HRQoL and costs.

RESULTS

HRQoL values declined, while total costs increased across disease severity. Total six-month healthcare costs and total societal costs were € 18,538 and € 66,789 respectively. Healthcare and societal costs doubled from early to middle phase, and tripled from middle to advanced disease phase. Main six-month cost components for the three disease phases were informal care costs (€ 30,605) accounting for approximately half the total societal costs, and costs due to production loss (€ 18,907) being slightly higher than the total healthcare costs. Disease severity and gender were found to have the strongest effect on both values of HRQoL and costs.

CONCLUSIONS

Reported values of HRQoL and costs including costs for production loss may be used in modelling the cost-effectiveness of treatment for HD. Our results highlight the crucial role the informal caregivers play in the care provided to HD patients in all disease phases. Future research should focus on the estimation of productivity loss among informal caregivers.

Preventive pharmacological treatment in subjects at risk for fatal familial insomnia: science and public engagement

Engaging patients as partners in biomedical research has gradually gained consensus over the last two decades. They provide a different perspective on health priorities and help to improve design and outcomes of clinical studies. This paper describes the relationship established between scientists and members of a large family at genetic risk of very rare lethal disease, fatal familial insomnia (FFI). This interaction led to a clinical trial based on the repurposing of doxycycline - an antibiotic with a known safety profile and optimal blood-brain barrier passage - which in numerous preclinical and clinical studies had given evidence of its potential therapeutic effect in neurodegenerative disorders, including prion diseases like FFI. The design of this trial posed several challenges, which were addressed jointly by the scientists and the FFI family. Potential participants excluded the possibility of being informed of their own FFI genotype; thus, the trial design had to include both carriers of the FFI mutation (10 subjects), and non-carriers (15 subjects), who were given placebo. Periodic clinical controls were performed on both groups by blinded examiners. The lack of surrogate outcome measures of treatment efficacy has required to compare the incidence of the disease in the treated group with a historical dataset during 10 years of observation. The trial is expected to end in 2023. Regardless of the clinical outcome, it will provide worthwhile knowledge on the disease. It also offers an important example of public engagement and collaboration to improve the quality of clinical science.

Disease Burden of Huntington's Disease (HD) on People Living with HD and Care Partners in Canada

Background:

Huntington’s disease (HD) has been shown to reduce health-related quality of life (HRQoL) and affect healthcare resource utilization (HRU) among patients and care partners internationally but has not been studied specifically in the Canadian context.

Objective:

To characterize the burden of HD on individuals with HD and care partners of individuals with HD in Canada.

Methods:

An online survey was distributed (September 14–November 23, 2020) through patient organizations to collect data on demographic and clinical characteristics, as well as: HRQoL, measured using the 36-Item Short-Form Health Survey (SF-36v1); HRU, measured using the Client Service Receipt Inventory (CSRI); and care partner burden, measured using the Caregiver Strain Index (CSI) and Huntington’s Disease Quality of Life Battery for Carers (HDQoL-C). Descriptive statistics were used to report data and compare subgroups.

Results:

A total of 62 adult individuals with HD (or their proxies) and 48 care partners met defined eligibility criteria. The mean [standard deviation] age was 51.2 [13.8] and 58.1 [13.9] years for individuals with HD and care partner respondents, respectively. For individuals with HD, the greatest HRQoL burden (i.e., lowest score) was for the SF-36v1 Role –Physical scale (46.8 [42.9]). HRU was higher for some services (e.g., general practitioner visits) for respondents who had experienced motor onset transition. Among care partners, 55.3% experienced high strain, as indicated by the CSI. The HDQoL-C showed the greatest HRQoL burden in feelings about life (45.1 [17.9]).

Conclusion:

This study quantified the substantial burden on individuals with HD and care partners in Canada, addressing a critical knowledge gap that can affect the availability of and access to healthcare services.

SUMO-modifying Huntington's disease

Small ubiquitin-like modifiers, SUMOs, are proteins that are conjugated to target substrates and regulate their functions in a post-translational modification called SUMOylation. In addition to its physiological roles, SUMOylation has been implicated in several neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases (HD). HD is a neurodegenerative monogenetic autosomal dominant disorder caused by a mutation in the CAG repeat of the huntingtin (htt) gene, which expresses a mutant Htt protein more susceptible to aggregation and toxicity. Besides Htt, other SUMO ligases, enzymes, mitochondrial and autophagic components are also important for the progression of the disease. Here we review the main aspects of Htt SUMOylation and its role in cellular processes involved in the pathogenesis of HD.

In vitro fertilization with preimplantation genetic testing for monogenetic diseases versus unassisted conception with prenatal diagnosis for Huntington disease: a cost-effectiveness analysis

OBJECTIVE

To investigate if in vitro fertilization (IVF) with preimplantation genetic testing for monogenic disease is cost effective for heterozygous individuals with Huntington disease vs. unassisted conception with prenatal diagnosis.

DESIGN

Cost-effectiveness analysis in a theoretical cohort of 3,851 couples, where one individual is heterozygous for Huntington disease.

SETTING

N/A.

PATIENTS/ANIMALS

None.

INTERVENTION

In vitro fertilization preimplantation genetic testing for couples attempting conception.

MAIN OUTCOME MEASURES

Outcomes included cost and quality-adjusted life years (QALYs) for both parents in addition to secondary outcomes of procedure-related loss, spontaneous abortion, termination of pregnancy, and early/normal/late-onset Huntington disease. A willingness-to-pay threshold was set at $100,000/QALY.

RESULTS

In vitro fertilization preimplantation genetic testing is lower in cost and higher in effectiveness compared to unassisted conception with prenatal diagnosis among couples with one heterozygous Huntington disease individual, making it the dominant strategy. In vitro fertilization preimplantation genetic testing was associated with 77 more QALYs and a cost savings of $46,394,268. All measured outcomes were lower in the IVF preimplantation genetic testing strategy, including 39 fewer procedure-related losses, 39 fewer spontaneous abortions, and 462 fewer terminations of pregnancy. Most notably, in our theoretical cohort of couples, IVF preimplantation genetic testing resulted in 1,079 fewer Huntington disease-affected offspring. Our results were robust over a wide range of assumptions.

CONCLUSION

In vitro fertilization preimplantation genetic testing is a cost-effective conception strategy compared to unassisted conception with prenatal diagnosis when one individual is heterozygous for Huntington disease. Not only can morbidity and mortality incurred by Huntington disease be mitigated for the offspring with the use of IVF preimplantation genetic testing, but this study demonstrates the cost-effectiveness of using IVF preimplantation genetic testing for those with Huntington disease.

Defining Utility Values for Chorea Health States in Patients with Huntington's Disease

Introduction

Chorea is characterized by sudden, involuntary movements that interfere with quality of life (QOL). Utility values measure preferences for different health states and reflect societal perceived disease severity. To date, no studies have reported utility values specifically for Huntington’s disease (HD) chorea. We estimated impact on QOL of HD chorea severity using utility values from the general population.

Methods

Participants were enrolled using computer-assisted telephone interviews. Participants read vignettes describing four health states for varying levels of chorea severity, with the same underlying HD severity. Time trade-off (TTO) methods were used to estimate utility values, which range from −1 (worse than death) to +1 (perfect health) and represent the number of years in an imperfect health state an individual is willing to give up to live in full health. TTO utilities were augmented with visual analog scale (VAS) participant responses. The primary outcome was HD chorea utility estimated by TTO.

Results

Mean ± SD TTO-derived utility values were 0.07 ± 0.52, 0.26 ± 0.50, 0.48 ± 0.47, and 0.64 ± 0.41 for severe, moderate/severe, moderate/mild, and mild chorea severity, respectively. Differences between each health state and its adjacent less severe health state were statistically significant (all P < 0.0001). Respondents were willing to give up 3.6, 5.2, 7.4, and 9.3 years during a 10-year life span to avoid living with mild, mild/moderate, moderate/severe, and severe chorea, respectively. VAS and TTO results were consistent.

Conclusions

Significant decreases in utility values were seen as HD chorea severity increased. These data can be leveraged for cost-effectiveness modeling to better understand the value of treatments for chorea.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02046-z.

Psychometric Properties and Validation of the Polish Version of the 12-Item World Health Organization Disability Assessment Schedule 2.0 in Patients with Huntington's Disease

BACKGROUND

Huntington's disease is a progressive neurodegenerative disorder that usually manifests in adulthood and is inherited in an autosomal dominant manner. The main aim of the study was to assess the psychometric properties of the 12-item WHO Disability Assessment Schedule (WHODAS) 2.0 in studying the level of disability in people with Huntington's disease.

METHOD

This is a cross-sectional study that covered 128 people with Huntington's disease living in Poland. We examined scale score reliability, internal consistency, convergent validity, and known-group validity. The disability and quality of life of people with Huntington's disease were also assessed.

RESULTS

The scale score reliability of the entire tool for the research group was high. The Cronbach's α test result for the whole scale was 0.97. Cronbach's α for individual domains ranged from 0.95 to 0.79. Time consistency for the overall result was 0.99 and for particular domains ranged from 0.91 to 0.99, which confirmed that the scale was consistent over time. All of the 12-item WHODAS 2.0 domains negatively correlated with all of the Huntington Quality of Life Instrument (H-QoL-I) domains. All correlation coefficients were statistically significant at the level of p < 0.001. The results obtained in the linear regression model showed that with each subsequent point of decrease in BMI the level of disability increases by an average of 0.83 points on the 12-item WHODAS 2.0 scale. With each subsequent year of the disease, the level of disability increases by an average of 1.39 points.

CONCLUSIONS

This is the first study assessing disability by means of the WHODAS 2.0 in the HD patient population in Poland, and it is also one of the few studies evaluating the validity of the WHODAS 2.0 scale in assessing the disability of people with HD in accordance with the recommendations of DSM-5 (R). We have confirmed that the 12-item WHODAS 2.0 is an effective tool for assessing disability and changes in functioning among people with Huntington's disease.