Cost-effectiveness of Anti-CD19 chimeric antigen receptor T-Cell therapy in pediatric relapsed/refractory B-cell acute lymphoblastic leukemia. A societal view.

INTRODUCTION: In several studies, the chimeric antigen receptor T-cell therapy tisagenlecleucel demonstrated encouraging rates of remission and lasting survival benefits in pediatric patients with relapsed/refractory (r/r) acute lymphoblastic leukemia (ALL). We assessed the cost-effectiveness of tisagenlecleucel (list price: 320 000 EUR) among these patients when compared to clofarabine monotherapy (Clo-M), clofarabine combination therapy (Clo-C), and blinatumomab (Blina) from both a healthcare and a societal perspective. We also assessed future medical and future non-medical consumption costs. METHODS: A three-state partitioned survival model was used to simulate a cohort of pediatric patients (12 years of age) through different disease states until the end of life (lifetime horizon). Relevant outcomes were life years, quality-adjusted life years (QALYs), healthcare costs, societal costs, and the incremental cost-effectiveness ratio (ICER). Uncertainty was explored through deterministic and probabilistic sensitivity analyses as well as through several scenario analyzes. RESULTS: Total discounted costs for tisagenlecleucel were 552 679 EUR from a societal perspective, which was much higher than the total discounted costs from a healthcare perspective (ie, 409 563 EUR). Total discounted societal costs for the comparator regimens ranged between 160 803 EUR for Clo-M and 267 259 EUR for Blina. Highest QALYs were estimated for tisagenlecleucel (11.26), followed by Blina (2.25), Clo-C (1.70) and Clo-M (0.74). Discounted societal ICERs of tisagenlecleucel ranged between 31 682 EUR/QALY for Blina and 37 531 EUR/QALY for Clo-C and were considered cost-effective with a willingness-to-pay (WTP) threshold of 80 000 EUR/QALY. None of the scenarios exceeded this threshold, and more than 98% of the iterations in the probabilistic sensitivity analysis were cost-effective. DISCUSSION: At the current price and WTP threshold, tisagenlecleucel is cost-effective from both a healthcare and a societal perspective. Nevertheless, long-term effectiveness data are needed to validate the several assumptions that were necessary for this model.

Measurement and evaluation of quality of life and well-being in individuals having or having had fertility problems: a systematic review.

OBJECTIVES: The aims of this study were: (1) to identify which measurement instruments are used in practice to assess the quality of life or well-being of individuals with and without (sub)fertility; (2) to describe the design and outcomes of studies comparing quality of life or well-being of individuals with and without fertility problems; and (3) to determine which of the outcomes of the identified studies could be used in cost-utility studies. METHODS: A systematic literature review was performed of studies published before July 2018, using multiple databases. Included studies investigated (health-related) quality of life or well-being of individuals with fertility problems. The applied instruments were assessed, as were the outcomes and suitability for use in cost-utility studies. RESULTS: Twenty-six studies met the inclusion criteria. Twelve distinct instruments of measurement were applied: two generic quality-of-life instruments, five generic well-being instruments and five disease-specific instruments. Most studies found negative associations in one or more domains assessing fertility problems and quality of life or well-being. However, two studies found the opposite. None of the studies reported outcomes relevant for cost-utility studies. CONCLUSION: Quality of life and well-being related to having fertility problems are regularly studied. However, the reported information is not suitable for use in cost-utility studies. There is a clear need for studies investigating the impact of fertility problems on quality of life in a way that outcomes can be compared across studies and disease areas.

Structural validity and internal consistency of the Qualidem in people with severe dementia.

BACKGROUND: Since its development, the Qualidem has had items that were considered unsuited for people with very severe dementia. This study attempted to investigate the applicability of all Qualidem items in people with all stages of dementia severity. METHODS: Four data sets that contained Qualidem observations on people with dementia were combined. Dementia severity was categorized based on the Global Deterioration Scale (GDS), with a dichotomization of very severe dementia (GDS 7) and others (GDS 1-6). Unidimensional latent-trait models (Mokken scaling) were estimated to fit the Qualidem responses in the overall sample and the dichotomized groups. Scalability was assessed using coefficients of homogeneity (Loevinger's H), while reliability was assessed with Cronbach's α and ρ. RESULTS: Combining the four databases resulted in 4,354 Qualidem measurements. The scalability of all scales was considered acceptable in the overall sample, as well is in the subgroups (all H > 0.3). Additionally, the reliability was good-excellent in the scales: "positive affect," "positive self-image," "care relationship," and "negative affect." Reliability was questionable-acceptable for "feeling at home," "social relations," "social isolation," and "restless tense behavior." Reliability was poor for "having something to do." CONCLUSIONS: Statistical considerations allow using all Qualidem items in all dementia stages. Future research should determine balance of statistical- versus conceptual-based reasoning in this academic debate.

A Simple and Practical Index to Measure Dementia-Related Quality of Life.

BACKGROUND: Research on new treatments for dementia is gaining pace worldwide in an effort to alleviate this growing health care problem. The optimal evaluation of such interventions, however, calls for a practical and credible patient-reported outcome measure. OBJECTIVES: To describe the refinement of the Dementia Quality-of-life Instrument (DQI) and present its revised version. METHODS: A prototype of the DQI was adapted to cover a broader range of health-related quality of life (HRQOL) and to improve consistency in the descriptions of its domains. A valuation study was then conducted to assign meaningful numbers to all DQI health states. Pairs of DQI states were presented to a sample of professionals working with people with dementia and a representative sample of the Dutch population. They had to repeatedly select the best DQI state, and their responses were statistically modeled to obtain values for each health state. RESULTS: In total, 207 professionals working with people with dementia and 631 members of the general population completed the paired comparison tasks. Statistically significant differences between the two samples were found for the domains of social functioning, mood, and memory. Severe problems with physical health and severe memory problems were deemed most important by the general population. In contrast, severe mood problems were considered most important by professionals working with people with dementia. DISCUSSION: The DQI is a simple and feasible measurement instrument that expresses the overall HRQOL of people suffering from dementia in a single meaningful number. Current results suggest that revisiting the discussion of using values from the general population might be warranted in the dementia context.

Quantification of health by scaling similarity judgments.

OBJECTIVE: A new methodology is introduced to scale health states on an interval scale based on similarity responses. It could be well suited for valuation of health states on specific regions of the health continuum that are problematic when applying conventional valuation techniques. These regions are the top-end, bottom-end, and states around 'dead'. METHODS: Three samples of approximately 500 respondents were recruited via an online survey. Each sample received a different judgmental task in which similarity data were elicited for the top seven health states in the dementia quality of life instrument (DQI). These states were '111111' (no problems on any domain) and six others with some problems (level 2) on one domain. The tasks presented two (dyads), three (triads), or four (quads) DQI health states. Similarity data were transformed into interval-level scales with metric and non-metric multidimensional scaling algorithms. The three response tasks were assessed for their feasibility and comprehension. RESULTS: In total 532, 469, and 509 respondents participated in the dyads, triads, and quads tasks respectively. After the scaling procedure, in all three response tasks, the best health state '111111' was positioned at one end of the health-state continuum and state '111211' was positioned at the other. The correlation between the metric scales ranged from 0.73 to 0.95, while the non-metric scales ranged from 0.76 to 1.00, indicating strong to near perfect associations. There were no apparent differences in the reported difficulty of the response tasks, but the triads had the highest number of drop-outs. DISCUSSION: Multidimensional scaling proved to be a feasible method to scale health-state similarity data. The dyads and especially the quads response tasks warrant further investigation, as these tasks provided the best indications of respondent comprehension.

Quality of life in dementia: a study on proxy bias.

BACKGROUND: Measurement of health-related quality of life (HRQoL) in dementia is difficult. At some point people with dementia become unable to meaningfully assess their own HRQoL. At such a point in time researchers need to rely on other types of information such as observation or assessments from informal caregivers (proxies). However, caregiver assessments may be biased by several mechanisms. The current study explores whether caregivers project part of their own HRQoL in their assessments of patient HRQoL. METHODS: The participants in the current study were 175 pairs, consisting of community-dwelling persons with dementia and their caregivers. The EQ-5D, the EQ-VAS and the QoL-AD were administered to collect HRQoL measurements from patients and caregivers at baseline, 6 months and 12 months. Two linear mixed models were used to investigate factors that bias proxy ratings, one with the EQ-VAS as dependent variable, and one with the EQ-5D utility as dependent variable. The independent variables were caregiver age, caregiver sex and caregiver QoL-AD items. RESULTS: The linear mixed model with EQ-VAS as dependent variable indicated that 3 caregiver characteristics, namely caregiver age, money (caregiver's financial situation) and valuation of life as a whole were significant predictors of the patient-by-proxy VAS scores. The linear mixed model with utility value as the dependent variable showed that caregiver age and valuation of the ability to do things for fun were significant predictors of the patient-by-proxy EQ-5D utility values. CONCLUSIONS: The current study was a first step in identifying factors that bias patient-by-proxy HRQoL assessments. It was discovered that caregivers project part of their own HRQoL onto patients when assessing patient HRQoL. This implies that patient-by-proxy HRQoL values should be interpreted with caution and not be used as a direct substitute for patient self-assessment, even when patients are no longer able meaningfully assess themselves.

Probabilistic choice models in health-state valuation research: background, theories, assumptions and applications.

Interest is rising in measuring subjective health outcomes, such as treatment outcomes that are not directly quantifiable (functional disability, symptoms, complaints, side effects and health-related quality of life). Health economists in particular have applied probabilistic choice models in the area of health evaluation. They increasingly use discrete choice models based on random utility theory to derive values for healthcare goods or services. Recent attempts have been made to use discrete choice models as an alternative method to derive values for health states. In this article, various probabilistic choice models are described according to their underlying theory. A historical overview traces their development and applications in diverse fields. The discussion highlights some theoretical and technical aspects of the choice models and their similarity and dissimilarity. The objective of the article is to elucidate the position of each model and their applications for health-state valuation.

Visual analogue scales: scale recalibration by patients with dementia and their proxies.

BACKGROUND: Visual analogue scales (VAS) are often used to measure health-related quality of life (HRQoL). However, when such scales contain ambiguous anchors like "best imaginable health state," they produce answers that are difficult to interpret, as such anchors are interpreted differently by respondents of different age. This phenomenon that people's interpretation of subjective response scales changes in response to changing circumstances is known as scale recalibration. The current study attempts to investigate whether scale recalibration in a patient sample with cognitive limitations and proxies differs from the general population. METHODS: The participants in the current study were 151 pairs of community-dwelling patients with dementia and their proxies. They were administered three VASs with different upper anchors; (A) "best imaginable health state," (B) "best imaginable health state for someone your age," and (C) "best imaginable health state for a 25-year-old." From literature, we inferred a conceptual model for the general population that predicts the ordinal relationship of the VASs to be B ≥ A ≥ C. This rank order is tested by repeated measure ANOVA's in the aforementioned populations. RESULTS: VAS scores of patients with dementia were in line with the conceptual model. Proxy VAS scores for assessing patient HRQoL were not in line with the model: A > B > C. In addition, proxy VAS scores for assessing their own health were not in line with the model: A > B > C. CONCLUSION: Patients with dementia use the VAS in a similar way to the general population. Proxies assessing either patients or themselves differ from the general population.

Validation study of the prototype of a disease-specific index measure for health-related quality of life in dementia.

BACKGROUND: Index measures for health-related quality of life (HRQoL) quantify the desirability (utility) of a certain health state. The commonly used generic index measure, e.g. EuroQol: EQ-5D, may underestimate relevant areas of specific diseases, resulting in lower validity. Disease-specific index measures on the other hand combine disease-specificity and quantification of perceived quality on several health domains of a certain disease into one single figure. These instruments have been developed for several diseases, but a dementia-specific HRQoL index instrument was not yet available. Facing the increasing individual and societal burden of dementia, specific HRQoL values with metric characteristics are especially useful because they will provide vital information for health outcome research and economic evaluations. AIMS OF THE STUDY: To develop and validate the prototype of a dementia-specific HRQoL index measure: Dementia Quality of life Instrument (DQI), as the first step towards valuation of the dementia health state. METHODS: For development of the DQI we created a conceptual framework based on a review of the literature, qualitative interviews with people with dementia and their carers, expert opinion and team discussion. To assess validity we undertook a survey under 241 dementia professionals. Measurements consisted of ranking (1-5) and rating (1-10) of 5 dementia-specific DQI domains (memory, orientation, independence, social activities and mood) and simultaneously rating of 9 DQI-derived health states on a visual analogue scale (VAS). We also performed a cross-sectional study in a large sample of people with very mild to moderate dementia and their caregivers (N=145) to assess feasibility and concurrent validity. In addition, caregivers valued 10 DQI and 10 EQ-5D + C derived health states of the patient simultaneously on the same VAS. SETTING: outpatient clinics, nursing homes and patient residences. RESULTS: All professionals judged the selected DQI domains to be relevant. Differences in ranking and rating behaviors were small. Mood was ranked (≥ 3.3) and rated (≥ 8.2) as most, orientation as least important (rank ≤ 2.6, value 7.5) health domain for dementia. For the validation part of this study the completion rates for all domains were above 98% for patients and 100% for caregivers on patients. A priori hypothesized DQI versus QOL-AD correlations that were significant in both patients and caregivers were: memory/memory, orientation/memory, independence/physical health, social activities/energy and mood/mood. Patient/caregiver inter-rater agreement was low (K <0.2) for memory/independence, fair (K 0.2-0.4) for orientation/mood, and moderate (K 0.4-0.6) for social activities. Concurrent validity of the DQI with the EQ-5D +C was moderate. The fact that most of the correlations between the domains of these two instruments were low (≤ 0.40) showed that both instruments measure different elements of health status. As expected, modest correlations (≥ 0.40) were observed between corresponding domains of the two instruments. CONCLUSIONS: Professionals judged all domains as relevant. The DQI prototype proved valid and feasible for patients and caregivers and is appropriate for very mild to moderate dementia. The differences in concurrent correlations with generic health status instruments imply that the dementia-specific DQI health domains indeed provide different information. The finding that patient HRQoL measured with the DQI was lower supports this notion. The new DQI shows comparable psychometric properties to the best available dementia-specific (QOL-AD) and generic (EQ-5D +C) measures. Further research is needed to generate values in the general population for each of the possible DQI states and to derive an algorithm that converts the 5 separate DQI domain scores into one single DQI Index score. Introducing the DQI Index will advance dementia-related HRQoL measurement by overcoming the shortcomings of generic and non-index instruments. This will allow more unequivocal interpretation of subjective dementia HRQoL states in dementia research.

Thurstone scaling revealed systematic health-state valuation differences between patients with dementia and proxies.

BACKGROUND: Conventional techniques to measure health-related quality of life (HRQoL) in a single value or index are complex, require abstract reasoning skills, and are prone to biases (e.g., adaptation). A possible alternative that requires less cognitive demand is Thurstone scaling. The present explorative study investigates the feasibility and concurrent validity of using Thurstone scaling to elicit health-state values in patients with dementia and their proxies. METHODS: The participants in the present study were 145 pairs, consisting of community-dwelling persons with dementia and their proxies. We administered the prototype of the dementia quality-of-life instrument (DQI), a dementia-specific HRQoL index instrument, to both patients and proxies. The patient's health state as defined by the DQI was placed randomly among nine other DQI health states and these were ranked from best to worst. These rankings were used for Thurstone scaling. After ranking, the health states were placed on a visual analogue scale (VAS). RESULTS: Thurstone scaling had a completion rate of 37% for patients and 88% for proxies. Thurstone scaling showed a high correspondence with VAS values. In addition, we identified a trend that shows that patients value most of the evaluated health states systematically lower than proxies. CONCLUSIONS: Thurstone scaling proved to be unfeasible for most patients, but feasible for proxies. Its concurrent validity was supported and new insights into patient-proxy discrepancies were discovered.