GIA imaging of 3-D mantle viscosity based on palaeo sea level observations - Part I: Sensitivity kernels for an Earth with laterally varying viscosity.

A key initial step in geophysical imaging is to devise an effective means of mapping the sensitivity of an observation to the model parameters, that is to compute its Fréchet derivatives or sensitivity kernel. In the absence of any simplifying assumptions and when faced with a large number of free parameters, the adjoint method can be an effective and efficient approach to calculating Fréchet derivatives and requires just two numerical simulations. In the Glacial Isostatic Adjustment problem, these consist of a forward simulation driven by changes in ice mass and an adjoint simulation driven by fictitious loads that are applied at the observation sites. The theoretical basis for this approach has seen considerable development over the last decade. Here, we present the final elements needed to image 3-D mantle viscosity using a dataset of palaeo sea-level observations. Developments include the calculation of viscosity Fréchet derivatives (i.e. sensitivity kernels) for relative sea-level observations, a modification to the numerical implementation of the forward and adjoint problem that permits application to 3-D viscosity structure, and a recalibration of initial sea level that ensures the forward simulation honours present-day topography. In the process of addressing these items, we build intuition concerning how absolute sea-level and relative sea-level observations sense Earth's viscosity structure and the physical processes involved. We discuss examples for potential observations located in the near field (Andenes, Norway), far field (Seychelles), and edge of the forebulge of the Laurentide ice sheet (Barbados). Examination of these kernels: (1) reveals why 1-D estimates of mantle viscosity from far-field relative sea-level observations can be biased; (2) hints at why an appropriate differential relative sea-level observation can provide a better constraint on local mantle viscosity and (3) demonstrates that sea-level observations have non-negligible 3-D sensitivity to deep mantle viscosity structure, which is counter to the intuition gained from 1-D radial viscosity Fréchet derivatives. Finally, we explore the influence of lateral variations in viscosity on relative sea-level observations in the Amundsen Sea Embayment and at Barbados. These predictions are based on a new global 3-D viscosity inference derived from the shear-wave speeds of GLAD-M25 and an inverse calibration scheme that ensures compatibility with certain fundamental geophysical observations. Use of the 3-D viscosity inference leads to: (1) generally greater complexity within the kernel; (2) an increase in sensitivity and presence of shorter length-scale features within lower viscosity regions; (3) a zeroing out of the sensitivity kernel within high-viscosity regions where elastic deformation dominates and (4) shifting of sensitivity at a given depth towards distal regions of weaker viscosity. The tools and intuition built here provide the necessary framework to explore inversions for 3-D mantle viscosity based on palaeo sea-level data.

Exploration of the Reasons Why Health State Valuation Differs for Children Compared With Adults: A Mixed Methods Approach.

OBJECTIVES: Evidence comparing utilities for adults and children consistently report higher utility values for child health states. This study investigates the reasons why child health states are valued differently. METHODS: A total of 80 respondents (United Kingdom, Belgium, The Netherlands) participated in 1.5-hour face-to-face interviews. Respondents valued 4 health states from 2 perspectives (8-year-old child, 40-year-old adult) using visual analog scale and time trade-off. A total of 32 respondents participated in think-aloud interviews. Audio recordings were analyzed by 2 independent coders using NVIVO software. Statements, nodes, and themes were reviewed cyclically until consensus was reached. RESULTS: Qualitative results: a total of 5 themes were identified in the data regarding child and adult valuation-intergenerational responsibility and dependency (childhood is crucial for forming life skills based on new experiences; adulthood is an important time to take care of the family), staying alive is important (life is worth living even with impaired health-related quality of life (HRQoL), for children and adults), awareness of poor HRQoL and ability to make decisions (children have difficulties comprehending poor HRQoL and their parents make their healthcare decision; adults can assess their own HRQoL and decide for themselves), coping ability (children are flexible and resilient; adults have experience with dealing with difficulties), and practical organization of care (children are cared for by their parents; adults are able to organize and pay for care). Mixed methods: comparing qualitative statements with respondents' higher utilities for child health states confirmed concordance between results. CONCLUSIONS: Quality-adjusted life-years are interpreted differently for children and adults. Child-specific value sets are needed to reflect society's preferences and to adequately conduct health technology assessment of pediatric treatments.

A stated preference survey to explore patient preferences for novel preventive migraine treatments.

OBJECTIVE: The objective of this study was to explore patient preference for attributes of calcitonin gene-related peptide (CGRP) inhibitors for the preventive treatment of migraine and to describe differences in treatment preferences between patients. BACKGROUND: CGRP inhibitors are a novel class of migraine drugs specifically developed for the preventive treatment of migraine. Clinicians should understand patient preferences for CGRP inhibitors to inform and support prescribing choices. METHODS: Patients with migraine in the US and Germany were recruited to participate in an online discrete choice experiment (DCE) survey, which presented hypothetical treatment choices using five attributes: mode of administration, side effects, migraine frequency, migraine severity, and consistency of treatment effectiveness. Attribute selection was informed by a literature review and semi-structured patient interviews (n = 35), and evaluated using patient cognitive debriefing interviews (n = 5). RESULTS: Of 680 who consented to participate, 506 participants completed the survey and were included in the study (US = 257; Germany = 249). Overall, participants placed highest importance (preference weight, beta = 1.65, p < 0.001) on the treatment's ability to reduce the severity of migraine (mild vs. unchanged severity), followed by consistent treatment effectiveness (beta = 1.13, p < 0.001), and higher chance of reduced migraine frequency (beta = 1.00, p < 0.001). Participants preferred an oral tablet every other day (beta = 1.00, p < 0.001) over quarterly infusion, quarterly injections (p = 0.019), or monthly injection (p < 0.001). Preference for all treatment attributes were heterogeneous, and the subgroup analyses found that participants naïve to CGRP monoclonal antibody treatments had a stronger preference for oral therapy compared to those with such experience (p = 0.006). CONCLUSION: In this DCE assessing CGRP inhibitors attributes, the main driver of patient choice was treatment effectiveness, specifically reduced migraine severity, and consistent treatment effectiveness. Further, patients exhibited an overall preference for an oral tablet every other day over injectables. Patients' experience with previous treatments informs the value they place on treatment characteristics.

Real-World experience of interictal burden and treatment in migraine: a qualitative interview study.

BACKGROUND: The debilitating nature of migraine attacks is widely established; however, less is known about how the interictal burden (i.e., how patients are affected in-between migraine episodes) of migraine impacts on patients' health-related quality of life (HRQL). Acute and preventive treatments may lift the burden of the disease, but they often have unwanted side effects and limited effectiveness. The objective of this study was to understand the interictal burden of migraines, from the patient perspective, and to explore patient experience with migraine treatments. METHODS: Participants (n=35) with a self-reported diagnosis of migraine were recruited in the US, UK and Canada, including a subgroup of patients who had taken calcitonin gene-related peptide monoclonal antibody (CGRP mAb) treatment for at least three months. Participants completed a background questionnaire, followed by a semi-structured interview via telephone or video call. The interviews explored patients' migraine symptoms, perception of interictal burden and treatment experience. The interview transcripts were analysed using thematic analysis. RESULTS: The most reported migraine symptom was migraine pain, followed by aura, sensory sensitivity and nausea. Most participants reported interictal impact on HRQL, lifestyle changes they made to avoid triggers or in anticipation of an attack, impacts on work, career, daily activities and relationships. Emotional impacts were reported by all participants, including anger, depression, anxiety and hopelessness. Many participants who took preventive treatments reported improvements in HRQL and functioning but still experienced breakthrough attacks. Among patients who took CGRP mAbs, participants noted varying consistency of treatment effectiveness between treatment administrations. CONCLUSION: This study detailed the additional HRQL impact of migraine in-between migraine attacks and described the unmet need for effective treatment options to prevent and mitigate migraine attacks.

Measuring interictal burden among people affected by migraine: a descriptive survey study.

BACKGROUND: Previous research has extensively documented the impact of migraine episodes ('ictal') on patients' health-related quality of life. Few studies have looked at the impact of migraine on migraine-free days ('interictal'). This study was designed to describe interictal burden of migraine in a mixed group of people affected by migraine and to explore patient characteristics associated with interictal burden. METHODS: People with migraine in the United States (US) and Germany were recruited for a cross-sectional online survey, including a subgroup treated with calcitonin gene-related peptide (CGRP) monoclonal antibody (mAb). The survey included the Migraine Interictal Burden Scale (MIBS-4), Headache Impact Test (HIT-6), and items measuring patient demographics, clinical and treatment background. Data were analyzed using descriptive statistics and linear regression. RESULTS: Five hundred six people with migraine completed the survey (US: n = 257; Germany: n = 249), of whom 195 had taken a CGRP mAb for three or more months. Participants had a mean of 8.5 (SD = 6.4) Monthly Migraine Days (MMD) and 10.4 (SD = 7.1) Monthly Headache Days (MHD). The mean MIBS-4 score was 6.3 (SD = 3.4), with 67% reporting severe interictal burden (MIBS-4: ≥5). The mean HIT-6 score was 65.3 (SD = 6.0), with 86% reporting severe migraine impact (HIT-6: ≥60). MIBS-4 was correlated with the HIT-6 (r = 0.37), MMD and MHD (both r = 0.27). The HIT-6, MMD, MHD, CGRP mAb treatment, and depression all had an independent positive association with the MIBS-4. CONCLUSION: Two-thirds of the study sample reported substantial interictal burden. Whilst interictal burden was associated with migraine frequency and impact of migraine attacks, study results also show it represented a distinct aspect of the overall disease burden. Study findings further indicate unique associations between interictal burden and depression. A unique positive association between interictal burden and CGRP mAb treatment suggests a remaining unmet need among people affected by migraine treated with CGRP mAb.

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.

Impact of developmental and epileptic encephalopathies on caregivers: A literature review.

OBJECTIVES: Developmental and epileptic encephalopathies (DEEs) are rare neurodevelopmental disorders characterized by early-onset seizures and numerous comorbidities. Due to the complex requirements for the care of a child with a DEE, these disorders would be expected to impact health-related quality of life (HRQL) for caregivers as well as for patients. The objective of this literature review was to describe the impact of DEEs on the HRQL, emotional wellbeing, and usual activities (social, work, relationships, etc.) of caregivers, including the wider impact on other family members such as siblings. METHODS: A literature search was conducted in May 2020 using MEDLINE® and Embase® databases. Quantitative and qualitative studies were identified using search terms related to family, disease type (including >20 specific DEEs), and quality of life/methodology. Each study was assessed for relevance and was graded using customized critical appraisal criteria. Findings from studies that were given the highest quality ratings were summarized and used to develop a conceptual model to illustrate the complex impact of DEEs on caregiver HRQL. RESULTS: Sixty-seven relevant studies were identified, of which 39 (27 quantitative, 12 qualitative) met the highest appraisal criteria. The studies recruited caregivers of patients with one of eight individual DEEs, or pediatric intractable or refractory epilepsy. Most studies reported negative impacts on HRQL and emotional wellbeing in caregivers. The wide-ranging impact of a DEE was highlighted by reports of negative effects on caregivers' physical health, daily activities, relationships, social activities, leisure time, work, and productivity. Factors that influenced the perceived impact included demographic characteristics (e.g., child's age, living arrangements, family income) and clinical factors (e.g., feeding or sleep difficulties, disease severity). Few studies evaluated the impact on siblings. CONCLUSIONS: There is evidence that DEEs can impact HRQL and emotional wellbeing and can limit usual activities for the primary caregiver and their wider family. However, no research was identified regarding many individual DEEs, and only limited research assessed the impact on different family members with most studies focusing on mothers. Further research is required to understand the influence of certain factors such as the age of the patient, disease severity, and seizures on caregiver burden. Furthermore, the review highlighted the lack of appropriate measurement tools to assess caregiver HRQL in this population.

Patient preferences for advanced hepatocellular carcinoma treatment: a multicountry stated preference study.

The present study aimed to explore patient preferences for attributes of advanced hepatocellular carcinoma (HCC) treatments. A stated preference survey was completed by 150 patients with HCC living in Europe. Overall survival (OS) was the most important attribute, closely followed by risk of diarrhea and hypertension, and other adverse event (AE) risks. Patients were willing to trade OS to reduce AE risks. While less important than OS and AEs, patients also preferred shorter waiting times, and one-off administration of selective internal radiation therapy and oral tablets over intravenous infusions. Although patients placed the most value on extending OS, they were willing to forego OS to avoid risk of treatment-related AEs, to maintain their quality of life.

Lay abstract This study aimed to understand patient preferences for characteristics of advanced hepatocellular carcinoma (HCC) treatments. A total of 150 people with HCC in Europe were presented a series of questions asking them to choose between two hypothetical treatments. Overall, length of life was the most important issue for patients, followed by avoiding diarrhea and hypertension, and then other side effects and treatment risks. Patients were willing to forego some months of life to avoid side effects or risks. Patients preferred to be given their treatment via a single minimally invasive hospital procedure or oral daily tablets compared with intravenous drips. In conclusion, although patients placed the most value on overall length of life, side effects and treatment risks were also important.

What Impact Does Venous Thromboembolism and Bleeding Have on Cancer Patients' Quality of Life?

BACKGROUND: Venous thromboembolism (VTE) is common in cancer patients and its treatment is associated with a high risk of recurrent VTE (rVTE) and bleeding. OBJECTIVES: To analyze data from the Comparison of Acute Treatments in Cancer Hemostasis (CATCH) trial to describe the impact of rVTE and bleeding events on health-related quality of life. METHODS: The three-level EuroQol five-dimensional questionnaire (EQ-5D) data were collected monthly for up to 7 months in patients starting anticoagulation for newly diagnosed VTE. Analyses were designed to describe the impact of rVTE and bleeding on EQ-5D scores while controlling for effects of covariates such as background and clinical variables and longitudinal changes. A repeated-measures model with specification of the variance-covariance matrix to characterize the intrapatient correlation was used to estimate the utility values. The impact of an rVTE or a bleeding event was assumed to be reflected in the utility value when it occurred within 2 weeks from a planned data collection point. RESULTS: Data were available from 883 patients. A total of 76 rVTE and 159 bleeding events occurred during follow-up. rVTE had a significant impact on EQ-5D scores, with a decrement of -0.075 on the basis of our reference case (male, no metastasis, Eastern Cooperative Oncology Group score = 1, Western European), but different patients might have different decrements. Bleeding events had a smaller (nonstatistically significant) impact on EQ-5D scores. CONCLUSIONS: This data set study has quantified the decline in EQ-5D scores associated with experiencing rVTE or bleeding events in cancer patients. These results indicate the net gain in quality of life and impact on cost-effectiveness of secondary VTE prevention.

Health-related quality of life in Parkinson's: impact of 'off' time and stated treatment preferences.

PURPOSE: Long-term levodopa therapy and related fluctuating plasma concentrations are associated with between-dose periods of 'off time' resulting in substantial variation in symptoms and functioning throughout the day in people with Parkinson's (PwP). METHODS: PwP across UK, France, Spain and Italy completed an online survey to explore: the impact of 'off time' on (1) health-related quality of life (HRQL) and (2) on functioning and ability to undertake usual activities; (3) the value of 'off time' relative to other factors associated with Parkinson's through a stated preference discrete choice experiment (SPDCE). RESULTS: In total, 305 PwP completed the online survey. Overall mean HRQL (utility) score was significantly lower for 'off time' (0.37) than for 'on time' (0.60). All attributes within the SPDCE were significant predictors of treatment choice, although increased duration of 'on time' (per hour per day: odds ratio (OR) = 1.40) and predictability of 'off time' to within 30 min (OR = 1.42) were valued most highly. CONCLUSIONS: 'On time' and predictability of 'off time' are highly valued by PwP. Due to substantial diurnal variation of Parkinson's symptoms, standard patient-reported outcome (PRO) assessments may not adequately capture the impact of 'off time' on HRQL and participation in daily activities.

Health-Related Quality of Life and Health Utilities in Metastatic Castrate-Resistant Prostate Cancer: A Survey Capturing Experiences from a Diverse Sample of UK Patients.

BACKGROUND: The collection of preference-based health outcomes data (or utility values) is required to support cost-effectiveness analyses. OBJECTIVE: This study aimed to collect health-related quality of life (HRQOL) data in men with metastatic castration-resistant prostate cancer (CRPC) stratified by disease states. METHODS: Men with metastatic CRPC were recruited via UK patient associations, patient panels, and specialist recruiters and classified into four subgroups reflecting disease state: asymptomatic/mildly symptomatic before chemotherapy, symptomatic before chemotherapy, receiving chemotherapy, and postchemotherapy. HRQOL data (including five-level EuroQol five-dimensional questionnaire [EQ-5D-5L], European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire [EORTC QLQ-C30], and 25-item prostate cancer-specific questionnaire module designed to supplement the EORTC QLQ-C30) along with background and medical history data were collected via an online survey. The EQ-5D-5L and the EORTC-8D (EORTC-8D is an 8 dimensional utility index scored from QLQ-C30 data) were both used to estimate utilities. RESULTS: Data were collected from a total sample of 163 men with metastatic CRPC. Utility values elicited by the EQ-5D-5L ranged from 0.830 for the asymptomatic/mildly symptomatic before chemotherapy disease state (95% confidence interval [CI] 0.795-0.865) to 0.625 for the symptomatic before chemotherapy disease state (95% CI 0.577-0.673). EORTC-8D utilities ranged from 0.856 (95% CI 0.831-0.882) to 0.697 (95% CI 0.664-0.731) for the same disease/treatment states. CONCLUSIONS: This online survey was designed to capture real-world HRQOL data describing men with CRPC. The study estimated utilities using two alternative methods, and the results show good agreement, suggesting that they are robust. This methodology offers a potentially higher quality alternative to vignette-based methods that are commonly used in oncology submissions.

Estimating utility values for non-alcoholic steatohepatitis health states: a discrete choice experiment.

Background: This study estimated utility values for non-alcoholic steatohepatitis (NASH). Previous studies have assumed that health-related quality of life does not vary between the early stages of NASH. Materials & Methods: Discrete choice experiment (DCE) surveys estimated the value of avoiding fibrosis progression. Patients also completed the EQ-5D-5L. Marginal rates of substitution estimated utility change associated with fibrosis progression. Results: DCE surveys were completed by the UK general public (n = 520) and patients with NASH (n = 154). The utility decline between fibrosis stages F1 and F4 decompensated was between -0.521 to -0.646 (depending on method). Conclusion: Three methods were used to estimate utilities for NASH, each one showed sensitivity to advancing fibrosis, including in the early stages, which is often considered asymptomatic.

Psychometric validation of the Visual Function Questionnaire-25 in patients with diabetic macular edema.

BACKGROUND: Diabetic Macular Edema (DME) is a common cause of impaired vision and blindness amongst diabetics. If not detected and treated early, the resulting vision loss can lead to considerable health costs and decreased health-related quality of life (HRQoL). The aim of this study was to provide evidence of the psychometric properties of the National Eye Institute - Visual Functioning Questionnaire (VFQ-25) for use in a cohort of DME patients who participated in a clinical efficacy and safety trial of pegaptinib sodium (Macugen). METHODS: A phase 2/3 randomised, double masked trial evaluated pegaptanib injection versus sham injection in patients with DME. The analysis was conducted using baseline HRQoL data of the VFQ-25 and the EQ-5D, on a modified intent-to-treat sample of 235 patients. These measures were administered by a trained interviewer by telephone in all but one of the study countries, where face-to-face interviews were conducted in the clinic. The measures were completed in the week prior to baseline, and after 54 weeks of treatment. Distance visual acuity, measured according to the Early Treatment Diabetic Retinopathy Study (ETDRS), was assessed at all time points. Psychometric properties of the VFQ-25 assessed included domain structure, reliability, concurrent and construct validity, responsiveness. RESULTS: The VFQ-25 was found to consist of 11 domains slightly different than those proposed. Nevertheless, none of the eight established multi-item scales met the criterion for further splitting and the VFQ-25 was scored as in the developers' instructions. Internal consistency reliability was demonstrated for six out of the eight original multi-item scales, with Cronbach's alpha ranging from 0.58 (Distance Activities) to 0.85 (Vision Specific: Dependency). The VFQ-25 domains generally showed a low to moderate correlation with EQ-5D visual analogue scale (range 0.16-0.43) and with the visual acuity score (range 0.10-0.41). Construct validity was upheld with higher VFQ-25 scores for patients who saw more letters according to the ETDRS. Almost all scales were shown to be responsive with Guyatt's statistic ranging from 0.10 to 0.56 at 54 weeks. CONCLUSIONS: The VFQ-25 has evidence to support its validity and reliability for measuring HRQoL in DME. However, some operating characteristics of the instrument need further consideration and discussion in the case of DME patients. Further research is therefore warranted in this indication.

A forgotten aspect of the NICE reference case: an observational study of the health related quality of life impact on caregivers of people with multiple sclerosis.

BACKGROUND: There are few published health technology assessments that have included the impact of a disease or treatment on caregivers' health related quality of life (HRQL). The objectives of this study were to explore the overall HRQL of caregivers of people with Multiple Sclerosis compared to matched controls, and more specifically explore the impact of different levels of functioning in people with MS on caregivers' HRQL scores. METHODS: A cross sectional observational study conducted as an online survey was undertaken in the UK. 200 caregivers of people with MS and 200 matched controls completed the EQ-5D, SF-36, HADS and a socio-demographic questionnaire. Caregivers also completed the Patient Determined Disease Steps questionnaire as a measure of MS severity. Differences in HRQL between caregivers and controls were assessed using t-tests and chi square analyses as appropriate. Ordinary Least Squares regression was also used to evaluate the disutility of being a caregiver compared to controls stratified by MS severity. RESULTS: Caregivers reported significantly lower HRQL, as measured by the SF-36, HADS and EQ-5D, compared to matched controls. A lower level of functioning in people with MS was mirrored by lower levels of caregivers' HRQL. At the point at which mobility problems required wheelchair use caregivers reported better HRQL. CONCLUSIONS: The potential impact of caregiving on HRQL is an important consideration for economic evaluations. In relation to MS, the results suggest that caregiver's HRQL deteriorates as the people with MS lose functioning; thus treatments that delay loss of function may have a benefit for caregivers as well as patients.

Is alpha-B crystallin an independent marker for prognosis in lung cancer?

BACKGROUND: Alpha B-crystallin (CRYAB) is an oncogene that increases tumour survival by promoting angiogenesis and preventing apoptosis. CRYAB is an independent prognostic marker in epithelial tumours including head and neck squamous cell carcinoma and breast cancer where it is predictive of nodal status and associated with poor outcome. We explored the role of CRYAB in non-small-cell lung cancer (NSCLC). METHODS: Immunohistochemical analysis was performed on 50 samples. Following staining with anti-alpha-B crystallin antibody, a blinded pathologist scored samples for nuclear (N) and cytoplasmic (C) staining intensity. Analysis was performed using Cox's proportional hazards model. RESULTS: There were 32 adenocarcinomas and 18 squamous cell carcinomas. The median tumour size was T2, grade 2 moderately differentiated, and 10 patients had nodal spread. Recurrence was seen in 22 patients (46%). Mortality was 48%, with median time to mortality 871 days. N staining was detected in eight samples (16%), and C staining in 20 (40%), with both N and C staining positive in five (10%). Staining for CRYAB predicted neither recurrence (N stain p=0.78, C stain p=0.38) nor mortality (N stain p=0.86, C stain p=0.66). CONCLUSION: CRYAB did not predict outcomes in patients treated for NSCLC. Larger studies are required to validate this finding.

Societal Utilities for Cognitive Impairment in Schizophrenia: Developing a Preference-Based Scoring Algorithm Based on the Schizophrenia Cognition Rating Scale.

INTRODUCTION: Loss of cognitive function is a common feature in schizophrenia. However, generic measures of health-related quality of life favored by decision-makers, such as the EQ-5D, are not designed to detect changes in cognitive function. We report the valuation of the Schizophrenia Cognition Rating Scale (SCoRS), a schizophrenia-specific measure of cognitive impairment. METHODS: Expert opinion and psychometric analysis of the SCoRS from clinical trial data was undertaken to select 5 key items from the measure. These items were combined orthogonally to develop health-state vignettes. Vignettes were valued using composite time trade-off (cTTO) in one-on-one video calls. Several econometric models were fitted to the data to estimate disutilities. Performance of EQ-5D- and SCoRS-based utilities were compared in the trial data. RESULTS: The SCoRS items selected for the valuation study represented attention, learning, processing speed, social cognition and memory. Four hundred respondents participated in the valuation study. The best observed health state was valued at 0.855 [standard deviation (SD) = 0.179] and the worst at 0.152 (SD = 0.575). At the most severe levels, 'social cognition' received the largest disutility followed by 'learning' and 'memory'. The final model to estimate utilities had 15 parameters. SCoRS-based utilities were sensitive to change in cognition, but the EQ-5D was not. CONCLUSION: It is feasible to value different dimensions of cognition separately using a validated instrument for proxy assessment. The resulting utilities indicate loss of quality of life due to reduced cognitive functioning.

Improving Interpretation of Evidence Relating to Quality of Life in Health Technology Assessments of Rare Disease Treatments.

Rare diseases are often severe, debilitating, life-limiting conditions, many of which occur in childhood. These complex conditions have a wide range of clinical manifestations that have a substantial impact on the lives of patients, carers and families and often produce heterogeneous clinical outcomes. Therefore, the evaluation of quality-of-life (QoL) impacts is important. In health technology assessment (HTA), patient-reported outcome measures (PROMs) and/or health state utility values (HSUVs) are used to determine QoL impacts of new treatments, but their use in rare diseases is challenging due to small and heterogeneous populations and limited disease knowledge. This paper describes challenges associated with the use of patient-reported outcomes (PROs)/HSUVs to evaluate QoL in HTA of rare disease treatments (RDTs) and identifies five recommendations to ensure appropriate interpretation of QoL impacts. These were derived from mixed methods research (literature reviews, appraisal document analyses, appraisal committee observations and interviews) examining the use of PROs/HSUVs in HTA of RDTs. They highlight that HTAs of RDTs must (1) understand the QoL impacts of the disease and of treatments; (2) critically assess PRO data, recognising the nuances in development and administration of PROMs/HSUVs, considering what is feasible and what matters most to the patient population; (3) recognise that lack of significant effect on a PRO does not imply no QoL benefit; (4) use different forms of evidence to understand QoL impacts, such as patient input; and (5) provide methodological guidance to capture QoL impacts on patients/carers.

Quality of Life with Late-Onset Pompe Disease: Qualitative Interviews and General Public Utility Estimation in the United Kingdom.

Background: Late-onset Pompe disease (LOPD) is a rare, progressive neuromuscular condition typically characterized by weakness of skeletal muscles, including those involved in respiration and diaphragmatic dysfunction. Individuals with LOPD typically eventually require mobility and/or ventilatory support. Objectives: This study aimed to develop health state vignettes and estimate health state utility values for LOPD in the United Kingdom. Methods: Vignettes were developed for 7 health states of LOPD with states defined in terms of mobility and/or ventilatory support. Vignettes were drafted based on patient-reported outcome data from the Phase 3 PROPEL trial (NCT03729362) and supplemented by a literature review. Qualitative interviews with individuals living with LOPD and clinical experts were conducted to explore the health-related quality-of-life (HRQoL) impact of LOPD and to review the draft vignettes. Vignettes were finalized following a second round of interviews with individuals living with LOPD and used in health state valuation exercises with people of the UK population. Participants rated the health states using the EQ-5D-5L, visual analogue scale, and time trade-off interviews. Results: Twelve individuals living with LOPD and 2 clinical experts were interviewed. Following the interviews, 4 new statements were added regarding dependence on others, bladder control problems, balance issues/fear of falling, and frustration. One hundred interviews with a representative UK population sample were completed. Mean time trade-off utilities ranged from 0.754 (SD = 0.31) (no support) to 0.132 (SD = 0.50) (invasive ventilatory and mobility support-dependent). Similarly, EQ-5D-5L utilities ranged from 0.608 (SD = 0.12) to -0.078 (SD = 0.22). Discussion: The utilities obtained in the study are consistent with utilities reported in the literature (0.670-0.853 for nonsupport state). The vignette content was based on robust quantitative and qualitative evidence and captured the main HRQoL impacts of LOPD. The general public rated the health states consistently lower with increasing disease progression. There was greater uncertainty around utility estimates for the severe states, suggesting that participants found it harder to rate them. Conclusion: This study provides utility estimates for LOPD that can be used in economic modeling of treatments for LOPD. Our findings highlight the high disease burden of LOPD and reinforce the societal value of slowing disease progression.

Patient and Caregiver Treatment Preferences in Type 2 and Non-ambulatory Type 3 Spinal Muscular Atrophy: A Discrete Choice Experiment Survey in Five European Countries.

BACKGROUND: Spinal muscular atrophy (SMA) is a rare neuromuscular disease that affects motor neurons, resulting in progressive skeletal muscle weakness and atrophy. OBJECTIVE: The aim of this study was to examine treatment preferences of patients and caregivers of patients with Type 2 and non-ambulatory Type 3 SMA in the Netherlands, Belgium, Finland, Ireland and Portugal. METHODS: A discrete choice experiment (DCE) survey was developed to elicit the preferences of adult patients and caregivers regarding different treatment aspects of SMA. This survey built on the design of a similar study undertaken in the UK. The DCE described choice questions in terms of attributes and levels combined using a D-efficient design. The attributes described improvements or worsening in motor and breathing function. The mode of treatment administration (intrathecal injection, single intravenous infusion or regular oral therapy) was described. Treatment risks and side effects related to currently available treatments including risk of liver injury, fatigue, headache, nausea, diarrhoea and rash were described. Lastly, an attribute described whether a treatment had evidence of treatment effectiveness in different SMA types. Participants were recruited via patient advocacy associations to complete an online survey. A clustered conditional logit model was used to estimate treatment preferences. RESULTS: Participants (n = 65) were 4.8 times and 8.1 times more likely to choose a treatment with stable or improved (vs worse) motor function, respectively. Similarly, participants were 4.3 times and 5.8 times more likely to choose stable or improved (vs worse) breathing function, respectively. Treatments with a risk of liver injury, fatigue, headache and nausea were 1.6 times less likely to be chosen than treatments with a risk of diarrhoea and rash. Treatments with demonstrated effectiveness in Type 1 SMA only were 2.3 times less likely to be chosen than those with demonstrated effectiveness in Types 1-3 SMA. Treatments administered via intrathecal injections were also 1.8 times less likely to be chosen than daily oral treatments. DISCUSSION: Study results show the importance of improvement as well as stabilisation of motor and breathing function to patients and caregivers, and a preference for oral treatments, treatments with demonstrated effectiveness in Types 2-3 SMA, and avoidance of liver injury risk.

Performance of the Toddler and Infant (TANDI) Health-Related Quality of Life Instrument in 3-4-Year-Old Children.

The Toddler and Infant (TANDI) dimensions of Health-Related Quality of Life assess 'age appropriate' behaviour and measurement could be extended to older children. A sample of 203 children 3-4 years of age was recruited, and their caregivers completed the TANDI, Pediatric Quality of Life Inventory (PedsQL) and EQ-5D-Y Proxy. Spearman and Pearson's correlation coefficients, and Kruskal-Wallis H-test were used to explore the feasibility, known-group validity, discriminate validity and concurrent validity of the TANDI. Children with a health condition (n = 142) had a lower ceiling effect (p = 0.010) and more unique health profiles (p < 0.001) than the healthy group (n = 61). The TANDI discriminated between those with and without a health condition. In children with a health condition, the TANDI discriminated between clinician rated severity of the health condition. The TANDI had moderate to strong correlations with similar PedsQL and EQ-5D-Y items and scores. The TANDI is valid for children aged 3-4 years and is recommended for children with a health condition, whereas the PedsQL may be better for healthy children. The TANDI is recommended for studies with young children whereas the EQ-5D-Y Proxy is recommended for a sample including older children or for longitudinal studies with preschoolers. Further work on the TANDI is recommended to establish test-retest reliability and responsiveness.