Differences In Mean Utilities Research Articles

Economic Outcomes of Rehabilitation Therapy in Older Patients With Acute Heart Failure in the REHAB-HF Trial

In the Rehabilitation Therapy in Older Acute Heart Failure Patients (REHAB-HF) trial, a novel 12-week rehabilitation intervention demonstrated significant improvements in validated measures of physical function, quality of life, and depression, but no significant reductions in rehospitalizations or mortality compared with a control condition during the 6-month follow up. The economic implications of these results are important given the increasing pressures for cost containment in health care. To report the economic outcomes of the REHAB-HF trial and estimate the potential cost-effectiveness of the intervention. The multicenter REHAB-HF trial randomized 349 patients 60 years or older who were hospitalized for acute decompensated heart failure to rehabilitation intervention or a control group; patients were enrolled from September 17, 2014, through September 19, 2019. For this preplanned secondary analysis of the economic outcomes, data on medical resource use and quality of life (via the 5-level EuroQol 5-Dimension scores converted to health utilities) were collected. Medical resource use and medication costs were estimated using 2019 US Medicare payments and the Federal Supply Schedule, respectively. Cost-effectiveness was estimated using the validated Tools for Economic Analysis of Patient Management Interventions in Heart Failure Cost-Effectiveness Model, which uses an individual-patient simulation model informed by the prospectively collected trial data. Data were analyzed from March 24, 2019, to December 1, 2020. Rehabilitation intervention or control. Costs, quality-adjusted life-years (QALYs), and the lifetime estimated cost per QALY gained (incremental cost-effectiveness ratio). Among the 349 patients included in the analysis (183 women [52.4%]; mean [SD] age, 72.7 [8.1] years; 176 non-White [50.4%] and 173 White [49.6%]), mean (SD) cumulative costs per patient were $26 421 ($38 955) in the intervention group (excluding intervention costs) and $27 650 ($30 712) in the control group (difference, -$1229; 95% CI, -$8159 to $6394; P = .80). The mean (SD) cost of the intervention was $4204 ($2059). Quality of life gains were significantly greater in the intervention vs control group during 6 months (mean utility difference, 0.074; P = .001) and sustained beyond the 12-week intervention. Incremental cost-effectiveness ratios were estimated at $58 409 and $35 600 per QALY gained for the full cohort and in patients with preserved ejection fraction, respectively. These analyses suggest that longer-term benefits of this novel rehabilitation intervention, particularly in the subgroup of patients with preserved ejection fraction, may yield good value to the health care system. However, long-term cost-effectiveness is currently uncertain and dependent on the assumption that benefits are sustained beyond study follow-up, which needs to be corroborated in future trials in this patient population.

Application of a Mapping Function to Estimate Utilities for Ragweed Allergy Immunotherapy Trials.

BackgroundRagweed pollen sensitivity is a common cause of allergic rhinitis (AR) worldwide. AR symptoms include itchy and runny eyes, sneezing, blocked nose, impaired sleep and social and emotional problems, which can have a significant impact on quality of life.ObjectiveThe objective of this analysis was to estimate utilities for two pooled standardised quality (SQ) ragweed sublingual immunotherapy (SLIT) tablet trials by applying a previously developed mapping algorithm. This study validated the algorithm and extended its application to ragweed seasonal allergy trials. The mapping algorithm relates disease-specific quality-of-life scores to preference-based utilities that may be used to calculate quality-adjusted life-years (QALYs) in cost-effectiveness studies.MethodsA mapping algorithm based on a grass pollen allergy immunotherapy trial, GT-08 (EudraCT no. 2004-000083-27) was applied to pooled data from two ragweed pollen immunotherapy trials, P05233 (EudraCT 2008-003863-38) and P05234 (EudraCT 2008-003864-20) to generate EuroQoL 5-Dimensions, 3-Levels (EQ-5D-3L) utilities from Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) data.ResultsThe mean utility difference between the SQ ragweed SLIT tablet and placebo was 0.025 [95% confidence interval (CI) 0.011–0.038]. The SQ ragweed SLIT tablet showed an incremental quality-adjusted life-days (QALDs) benefit of 1.900 (95% CI 0.835–2.916) over 75 days.ConclusionsApplication of a previously developed mapping function allowed for the calculation of QALDs associated with the SQ ragweed SLIT tablet. The results showed a QALD benefit of the SQ ragweed SLIT tablet in P05233 and P05234 trials in the treatment of ragweed pollen-induced AR.

PRM41 - Development of an Online Time Trade off Methods for Health State Valuation

Face to face time trade off (TTO) applications are expensive and time consuming. Therefore, it is important to explore an alternative robust online application for this classical valuation method. This study assessed the feasibility of using an online TTO method to elicit preferences for health states defined by the EQ-5D-5L classification system. An online panel (n=400) between 18 to 73 years of age was recruited for this study with the sample demographically similar to the Australian general population. The TTO procedure was developed following the TTO user manual from the University of York. Eighty six EQ-5D-5L health states were directly valued. Each respondent was given a randomly selected 10 health states to value as compared with full health (‘11111’). Basic demographics, co-morbidities and visual analogue scale data were also collected. The direct valuation of 86 health states from this online study were compared with the modelled values based on the Australian EQ-5D-5L algorithm based on discrete choice experiment (DCE). The degree of agreement between the two measures were determined using the Pearson and intra class correlation. There were 4,280 observations. Direct utility measures recorded as 0.5 (n=1,106) were excluded as it improves the agreement. Mean utility difference between this study and those calculated based on DCE approach was -0.03 (SD=0.24). Pearson correlation and ICC were 0.84 and 0.75 respectively. Further analysis need to be conducted to assess the reliability of excluded data. There are substantial similarities between the recorded direct valuation based on this online task and the derived values from the online DCE task used to develop the Australian EQ5D-5L algorithm. Further improvements to the online methods, such as including a confirmatory question for responses of 0.5 are suggested for further consideration.

Test-Retest Reliability of Discrete Choice Experiment for Valuations of QLU-C10D Health States

BackgroundRecently, a newly developed cancer-specific multiattribute utility instrument based on the widely used health-related quality of life instrument, the European Organisation for Research and Treatment of Cancer QLQ-C30, was introduced: the QLU-C10D. For the elicitation of utility weights, a discrete choice experiment (DCE) was designed. Our aim was to investigate the DCE in terms of individual choice consistency and utility estimate consistency by applying a test-retest design. MethodsWe conducted the study in general population samples in Germany and France. The DCE was administered via a web-based self-complete survey using online panels. Respondents were presented 16 choice sets comprising 11 attributes with 4 levels each. Retest was conducted 4 to 6 weeks after first assessment. We used kappa and percentage agreement as measures of choice consistency and both intraclass correlations and mean utility differences as measures of utility estimate consistency. ResultsA total of 300 German respondents (31% female, mean age 48 years [SD 14]) and 305 French respondents (46% female, mean age 47 years [SD 16]) completed test and retest assessments. Individual choice consistency was moderate to high (Germany: κ = 0.605, percentage agreement = 80.2%; France: κ = 0.411, percentage agreement = 70.6%). Utility estimate consistency was high when considering intraclass correlations (all >0.79). Mean utility differences were 0.08 in the German sample and 0.05 in the French sample. ConclusionsResults indicate that the designed DCE elicits stable health state preferences rather than guesses or mood-specific or condition-specific judgments. Nevertheless, the identified mean utility differences between test and retest need to be taken into account when determining minimal important differences for the QLU-C10D in future research.

Valuing Treatments for Parkinson Disease Incorporating Process Utility: Performance of Best-Worst Scaling, Time Trade-Off, and Visual Analogue Scales

ObjectiveThe objective of this study was to compare treatment profiles including both health outcomes and process characteristics in Parkinson disease using best-worst scaling (BWS), time trade-off (TTO), and visual analogue scales (VAS). MethodsFrom the model comprising of seven attributes with three levels, six unique profiles were selected representing process-related factors and health outcomes in Parkinson disease. A Web-based survey (N = 613) was conducted in a general population to estimate process-related utilities using profile-based BWS (case 2), multiprofile-based BWS (case 3), TTO, and VAS. The rank order of the six profiles was compared, convergent validity among methods was assessed, and individual analysis focused on the differentiation between pairs of profiles with methods used. ResultsThe aggregated health-state utilities for the six treatment profiles were highly comparable for all methods and no rank reversals were identified. On the individual level, the convergent validity between all methods was strong; however, respondents differentiated less in the utility of closely related treatment profiles with a VAS or TTO than with BWS. For TTO and VAS, this resulted in nonsignificant differences in mean utilities for closely related treatment profiles. ConclusionsThis study suggests that all methods are equally able to measure process-related utility when the aim is to estimate the overall value of treatments. On an individual level, such as in shared decision making, BWS allows for better prioritization of treatment alternatives, especially if they are closely related. The decision-making problem and the need for explicit trade-off between attributes should determine the choice for a method.

Adopting a Patient-Centered Approach to Primary Outcome Analysis of Acute Stroke Trials Using a Utility-Weighted Modified Rankin Scale.

Although the modified Rankin Scale (mRS) is the most commonly used primary end point in acute stroke trials, its power is limited when analyzed in dichotomized fashion and its indication of effect size challenging to interpret when analyzed ordinally. Weighting the 7 Rankin levels by utilities may improve scale interpretability while preserving statistical power. A utility-weighted mRS (UW-mRS) was derived by averaging values from time-tradeoff (patient centered) and person-tradeoff (clinician centered) studies. The UW-mRS, standard ordinal mRS, and dichotomized mRS were applied to 11 trials or meta-analyses of acute stroke treatments, including lytic, endovascular reperfusion, blood pressure moderation, and hemicraniectomy interventions. Utility values were 1.0 for mRS level 0; 0.91 for mRS level 1; 0.76 for mRS level 2; 0.65 for mRS level 3; 0.33 for mRS level 4; 0 for mRS level 5; and 0 for mRS level 6. For trials with unidirectional treatment effects, the UW-mRS paralleled the ordinal mRS and outperformed dichotomous mRS analyses. Both the UW-mRS and the ordinal mRS were statistically significant in 6 of 8 unidirectional effect trials, whereas dichotomous analyses were statistically significant in 2 to 4 of 8. In bidirectional effect trials, both the UW-mRS and ordinal tests captured the divergent treatment effects by showing neutral results, whereas some dichotomized analyses showed positive results. Mean utility differences in trials with statistically significant positive results ranged from 0.026 to 0.249. A UW-mRS performs similar to the standard ordinal mRS in detecting treatment effects in actual stroke trials and ensures the quantitative outcome is a valid reflection of patient-centered benefits.

Health state utilities associated with major clinical events in the context of secondary hyperparathyroidism and chronic kidney disease requiring dialysis.

BackgroundPatients with chronic kidney disease (CKD) and secondary hyperparathyroidism (SHPT) who require dialysis are at increased risk for cardiovascular events and bone fractures. To assist in economic evaluations, this study aimed to estimate the disutility of these events beyond the impact of CKD and SHPT.MethodsA basic one-year health state was developed describing CKD and SHPT requiring dialysis. Further health states added acute events (cardiovascular events, fractures, and surgical procedures) or chronic post-event effects. Acute health states described a year including an event, and chronic health states described a year subsequent to an event. General population participants in Canada completed time trade-off interviews from which utilities were derived. Pairwise comparisons were made between the basic state and event, and between comparable health states.ResultsA total of 199 participants (54.8% female; mean age = 46.3 years) completed interviews. Each health state had ≥130 valuations. The mean (SD) utility of the basic health state was 0.60 (0.34). For acute events, mean utility differences versus the basic state were: myocardial infarction, −0.06; unstable angina, −0.05; peripheral vascular disease (PVD) with amputation, −0.33; PVD without amputation, −0.11; heart failure, −0.14; stroke, −0.30; hip fracture, −0.14; arm fracture, −0.04; parathyroidectomy, +0.02; kidney transplant, +0.06. Disutilities for chronic health states were: stable angina, −0.09; stroke, −0.27; PVD with amputation, −0.30; PVD without amputation, −0.12; heart failure, −0.14.ConclusionsCardiovascular events and fractures were associated with lower utility scores, suggesting a perceived decrease in quality of life beyond the impact of CKD and SHPT.Electronic supplementary materialThe online version of this article (doi:10.1186/s12955-015-0266-9) contains supplementary material, which is available to authorized users.

Estimating the burden of disease in chronic pain with and without neuropathic characteristics: Does the choice between the EQ-5D and SF-6D matter?

The EQ-5D and Short Form (SF)12 are widely used generic health-related quality of life (HRQoL) questionnaires. They can be used to derive health utility index scores, on a scale where 0 is equivalent to death and 1 represents full health, with scores less than zero representing states “worse than death.” We compared EQ-5D or SF-6D health utility index scores in patients with no chronic pain, and chronic pain with and without neuropathic characteristics (NC), and to explore their discriminant ability for pain severity. Self-reported health and chronic pain status was collected as part of a UK general population survey (n=4451). We found moderate agreement between individual dimensions of EQ-5D and SF-6D, with most highly correlated dimensions found for mental health and anxiety/depression, role limitations and usual activities, and pain and pain/discomfort. Overall 43% reported full health on the EQ-5D, compared with only 4.2% on the SF-6D. There were significant differences in mean utilities for chronic pain with NC (EQ-5D 0.47 vs SF-6D 0.62) and especially for severe pain (EQ-5D 0.33 vs SF-6D 0.58). On the EQ-5D, 17% of those with chronic pain with NC and 3% without NC scored “worse than death,” a state which is not possible using the SF-6D. Health utilities derived from EQ-5D and SF-12/36 can discriminate between group differences for chronic pain with and without NC and greater pain severity. However, the instruments generate widely differing HRQoL scores for the same patient groups. The choice between using the EQ-5D or SF-6D matters greatly when estimating the burden of disease.

BMI, Health Behaviors, and Quality of Life in Children and Adolescents: A School-Based Study

To explore the relationship between weight status (BMI) and health-related quality of life in children and adolescents through application of the Child Health Utility 9D, a new generic preference-based instrument. Data were collected from primary and high school students in rural and metropolitan regions of South Australia. Consenting participants (2588 in grades 4-6 and 765 in grades 9-10) were weighed and measured and categorized as underweight, healthy weight, overweight, or obese according to International Obesity Taskforce BMI cutoff points (primary outcome). Participants also completed a questionnaire including the Child Health Utility 9D and standardized measures of physical activity, sedentary behavior, sleep patterns, and eating behavior (secondary outcomes). Descriptive and multivariate linear regression analyses were undertaken to calculate mean utility differences. In comparison with healthy-weight primary school students, adjusted mean utilities were lower for overweight (-0.016, P = .02) or obese (-0.039, P = .001) students. For high school students, the adjusted mean utilities were also lower for overweight and obese students but were nonsignificant (-0.018, P > .10). Physical activity, sedentary behavior, sleep patterns, and eating behavior were all found to be significantly associated with utilities. Irrespective of BMI, young people engaging in more physical activities or less sedentary behavior, and having healthier sleep patterns or eating behavior exhibited higher utilities. Associations between utilities and sleep patterns or eating behavior were stronger than the associations with BMI. Future economic evaluations for obesity interventions should more formally investigate the relationship between changes over time in weight status and health-related quality of life for children and adolescents.

The utility score of epilepsy with partial seizure measured by TTO, VAS, and EQ-5D in the general Korean population

This study aimed to measure utilities, which are quantitative terms incorporating preferences, for various health states of epilepsy with partial seizure in the general population in South Korea. It also aimed to find socio-demographic characteristics associated with the utility scores. Utility scores using Time Trade-Off (TTO), Visual Analog Scale (VAS), and EuroQol five Dimension (EQ-5D) were obtained from 300 people aged 16 and over by face-to-face interviews. We measured utilities for three hypothetical health states of epilepsy for which scenarios were defined based on the frequency of partial seizure: seizure-free, seizure reduction, and withdrawal. We compared utilities with varying seizure frequency using a repeated-measures ANOVA, and analyzed the association between utilities and socio-demographic characteristics using a generalized estimating equation (GEE). The mean utility scores for withdrawal state, seizure reduction state, and seizure-free state were 0.303, 0.493, and 0.899, respectively, when measured by TTO. VAS yielded the mean utility scores of 0.211, 0.424, and 0.752 for respective health states, and corresponding scores with EQ-5D were 0.261, 0.645, and 0.959. The utility scores for the three health states were statistically different in TTO, VAS, and EQ-5D. The withdrawal state had the lowest utility scores. There were differences in mean utilities for the three health states across the three methods. Utilities by EQ-5D tended to have higher values than those by TTO and VAS. Utilities by VAS had the lowest values. In GEE analysis, the severity of epilepsy and household income were significantly related to utility scores. The withdrawal state of epilepsy had the lowest utility value and the seizure-free state had the highest by all three techniques of utility measurement used. There were significant differences in utilities between one severity level of epilepsy and another. Utility was associated with household income and the severity of disease. Utility scores for distinct epilepsy states obtained in this study could facilitate health economic analyses of epilepsy treatments and thus help decision making in resource allocation.

Impact of caregiver and parenting status on time trade-off and standard gamble utility scores for health state descriptions

BackgroundThe purpose of this study was to examine the effect of caregiver status on time trade-off (TTO) and standard gamble (SG) health state utility scores. Respondents were categorized as caregivers if they reported that either children or adults depended on them for care.MethodsThis study was a secondary analysis of data from three studies in which general population samples rated health state descriptions. Study 1: UK; four osteoarthritis health states. Study 2: UK; three adult ADHD health states. Study 3: US; 16 schizophrenia health states. All three studies included time trade-off assessment. Study 1 also included standard gamble. Descriptive statistics were calculated to examine willingness to trade in TTO or gamble in SG. Utilities for caregivers and non-caregivers were compared using t-tests and ANCOVA models.ResultsThere were 364 respondents including 106 caregivers (n = 30, 47, and 29 in Studies 1, 2, and 3) and 258 non-caregivers. Most caregivers were parents of dependent children (78.3%). Compared to non-caregivers, caregivers had more responses at the ceiling (i.e., utility = 0.95), indicating less willingness to trade time or gamble. All utilities were higher for caregivers than non-caregivers (mean utility difference between groups: 0.07 to 0.16 in Study 1 TTO; 0.03 to 0.17 in Study 1 SG; 0.06 to 0.10 in Study 2 TTO; 0.11 to 0.22 in Study 3 TTO). These differences were statistically significant for at least two health states in each study (p < 0.05). Results of sensitivity analyses with two caregiver subgroups (parents of dependent children and parents of any child regardless of whether the child was still dependent) followed the same pattern as results of the primary analysis. The parent subgroups were generally less willing to trade time or gamble (i.e., resulting in higher utility scores) than comparison groups of non-parents.ConclusionsResults indicate that caregiver status, including being a parent, influences responses in time trade-off health state valuation. Caregivers (i.e., predominantly parents) were less willing than non-caregivers to trade time, resulting in higher utility scores. This pattern was consistent across multiple health states in three studies. Standard gamble results followed similar patterns, but with less consistent differences between groups. It may be useful to consider parenting/caregiving status when collecting, interpreting, or using utility data because this demographic variable could influence results.

Estimation of a Multiattribute Utility Function for the Spanish Version of the TooL Questionnaire

Objectives To estimate and assess the psychometric properties of a multiattribute utility function (MAUF) for the Spanish version of the Tolerability and Quality of Life (TooL questionnaire). Methods Balanced data on 243 patients diagnosed with schizophrenia or bipolar disorder were gathered. In addition to the demographic and clinical variables and the usual generic health-related quality of life (HRQoL) questionnaires (EuroQol-5D [EQ-5D] and Short Form-6D [SF-6D]), instruments considered included the Spanish versions of the Positive and Negative Symptoms of Schizophrenia Scale (PANSS), Young Mania Rating Scale (YMRS), Montgomery-Asberg Depression Rating Scale (MADRS), Udvalg for Kliniske Undersogelser (UKU), and Clinical Global Impression Severity (CGIS) scale. MAUF parameters estimation involved a number of visual analogue scale (VAS) and time trade-off (TTO) ratings that proved difficult to be performed by the patients. After checking for inconsistencies in patient responses, the original sample was reduced to a still balanced subsample of 70 individuals. A multiplicative-form MAUF was estimated following the standard methodology. Results Good convergent validity was demonstrated because utility estimates from the MAUF presented strong correlations with utilities from the generic HRQoL instruments included: SF-6D (0.66, P < 0.01), EQ-5D (0.69, P < 0.01), and moderate correlations with the rest of instruments considered: PANSS (−0.27, P = 0.10), YMRS (−0.30, P = 0.08), MADRS (−0.48, P < 0.01), UKU (−0.35, P < 0.01). Criterion validity was also met because differences in mean utilities by clinical severity were found ( P < 0.01). Utilities from the MAUF covered a wider range of health states [0.04,1.00] than those from the SF-6D [0.53,1.00] and EQ-5D [0.23,0.96]. Conclusions Utilities from the MAUF showed good psychometric properties, serving as a complement to generic health utilities. If misapplied, however, utilities from this instrument might favor the positive evaluation of drugs showing fewer associated side effects.

Comparison and correlates of three preference-based health-related quality-of-life measures among overweight and obese women with urinary incontinence

To compare three preference-based health-related quality-of-life (HRQL) measures and examine independent correlates of HRQL among overweight and obese women with urinary incontinence (UI) enrolled in a weight loss intervention trial. Participants completed baseline questionnaires, which included the Health Utilities Index 3 (HUI3) and Medical Outcomes Study Short Form-36 (SF-36). The SF-36 was used to derive SF-6D and estimated Quality of Well-Being (eQWB) scores. Height, weight, medical history, incontinence measures, and level of physical activity also were assessed. The intraclass correlation coefficient (ICC) was computed, and differences in mean scores across HRQL measures were examined. Potential correlates of HUI3, SF-6D, and eQWB scores were evaluated using multivariable generalized linear models. Mean±SD scores for the HUI3, SF-6D, and eQWB were 0.81±0.18, 0.75±0.10, and 0.71±0.06, respectively. Significant differences were observed across measures (P<0.0001), and the overall ICC was 0.36. In multivariable analyses, BMI was negatively associated with HUI3 (P=0.003) and eQWB (P<0.001), and UI episode frequency was negatively associated with eQWB (P=0.015) and SF-6D (P<0.001). Significant differences in mean utilities across the HUI3, SF-6D, and eQWB indicate that these measures do not assess identical dimensions of HRQL. Both BMI and UI episode frequency were related to HRQL in this cohort; however, the magnitude of the relationship depended on the preference-based measure used. These findings highlight the need to consider the method used to generate HRQL values for calculating quality-adjusted life-years in cost-utility analyses, since choice of method may have a substantial impact on the outcome of the analysis.

The precision of health state valuation by members of the general public using the standard gamble

Precision is a recognised requirement of patient-reported outcome measures but no previous studies of the precision of methods for obtaining health state values from the general public, based on specific health state descriptions or vignettes, have been carried out. The methodological requirements of policy makers internationally is driving growth in the use of methods to obtain utilities from the general public to inform cost per quality-adjusted life-year (QALY) analyses of health technologies being considered for adoption by health systems. The precision of five comparisons of the outcomes of treatments, based on health state descriptions, was assessed against the results of clinical trials which showed a statistically and clinically significant improvement using an internet panel of members of the UK general public. Health states were developed to depict the baseline and post-treatment states from these exemplar clinical trials. Preferences for health states were obtained using bottom-up titrated standard gamble over the internet, and differences between summary health state values corresponding to the treatment and comparator groups within each exemplar study were compared. Results are considered in the context of various estimates for the minimally important difference in utility values. Participation among members of the internet panel in the five exemplars ranged from 27 to 59. In four of the five exemplars, the utility-based estimates of treatment benefit showed significant differences between groups and were greater than an assumed minimally important difference of 0.1. Mean utility differences between groups were: 0.23 (computerised cognitive behavioural therapy for depression, P < 0.001), 0.11 (hip resurfacing for hip osteoarthritis, P < 0.001), 0.0005 (cognitive behavioural therapy for insomnia, P = 0.98), 0.15 (pulmonary rehabilitation for COPD, P < 0.001) and 0.11 (infliximab for Crohn's disease, P < 0.001). The confidence intervals around the estimates of utility-based treatment effect in three of the five examples did not exclude the possibility of a difference smaller than a minimally important difference of 0.1. Recent empirical evidence suggests a lower minimally important difference (0.03) may be more appropriate, in which case our results provide further reassurance of preservation of precision in health state description and valuation. The precision of estimates of treatment effects based on preference data obtained from disease-specific measurements in clinically significant studies of health technologies was acceptable using an internet-based panel of members of the general public and the standard gamble. Definition of the minimally important difference in utility estimates is required to adequately assess precision and should be the subject of further research.

Comparing SF-6D and EQ-5D utilities across groups differing in health status

To compare the EQ-5D and SF-6D within socio-demographic and clinical groups in a representative sample (n = 1,005) of the Greek general population and to examine mean utility differences across groups differing in health in this population and in a highly morbid disease sample (diabetes, n = 215). Association and level of agreement between instruments were estimated with Pearson's r and the intraclass correlation coefficient (ICC), respectively. Paired-samples t-test was used to identify significant score differences, which were regarded as minimally important differences (MID) when they exceeded 0.03. The EQ-VAS was used to classify individuals into health status groups, covering the range from very poor to very good health, and the same classification was used in the diabetes sample. EQ-5D and SF-6D were in agreement and strongly correlated over the entire sample (ICC = 0.536, P < 0.001 and r = 0.662, P < 0.001), but correlation varied according to socio-demographic factors and clinical conditions. In healthier responders, EQ-5D scores were significantly higher than SF-6D scores (P < 0.001) and differences constituted MIDs. Contrarily, in individuals with clinical conditions, SF-6D scores were predominantly higher than EQ-5D. The pattern of results was replicated in the disease sample as well. The hypotheses that EQ-5D generates higher scores in healthier populations and the SF-6D in less healthier groups were confirmed. Based on the evidence provided here, EQ-5D and SF-6D measuring discrepancies generate utility differences across VAS-based health groups, which warrant further within-sample investigation.

Using a heterogeneous multinomial probit model with a neural net extension to model brand choice

AbstractThe multinomial probit model introduced here combines heterogeneity across households with flexibility of the (deterministic) utility function. To achieve flexibility deterministic utility is approximated by a neural net of the multilayer perceptron type. A Markov Chain Monte Carlo method serves to estimate heterogeneous multinomial probit models which fulfill economic restrictions on signs of (marginal) effects of predictors (e.g., negative for price). For empirical choice data the heterogeneous multinomial probit model extended by a multilayer perceptron clearly outperforms all the other models studied. Moreover, replacing homogeneous by heterogeneous reference price mechanisms and thus allowing price expectations to be formed differently across households also leads to better model performance. Mean utility differences and mean elasticities w.r.t. price and price deviation from reference price demonstrate that models with linear utility and nonlinear utility approximated by a multilayer perceptron lead to very different implications for managerial decision making. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Maximising Responses to Discrete Choice Experiments

To identify any differences in response and completion rates across two versions of a questionnaire, in order to determine the trade-off between a potentially higher response rate (from a short questionnaire) and a greater level of information from each respondent (from a long questionnaire). This was a randomised trial to determine whether response rates and/or results differ between questionnaires containing different numbers of choices: a short version capable of estimating main effects only and a longer version capable of estimating two-way interactions, provided certain assumptions hold. Best-worst scaling was the form of discrete choice experimentation used. Data were collected by post and analysed in terms of response rates, completion rates and differences in mean utilities. Fifty-three percent of individuals approached agreed to take part. From these, the response to the long questionnaire was 83.2% and the short questionnaire was 85.1% (difference 1.9%, 95% CI -7.3, 11.2; p = 0.68). The two versions of the questionnaire provided similar inferences. This trial indicates that, in a healthcare setting, for this complexity of questionnaire (i.e. four attributes and the best-worst scaling design), the use of 16 scenarios obtained very similar response rates to those obtained using half this number.

Preference elicitation using the time trade-off method in patients with 1 to 3 newly diagnosed brain metastases in a prospective randomized clinical trial comparing radiosurgery with and without whole brain radiation

Materials/Methods: A time trade-off instrument was developed to directly elicit preferences from patients on the trial. The elicitation instrument included a written script, data collection form, and visual aid to facilitate the understanding of trading time. The instrument was administered face-to-face during patient clinic visits at baseline, 1, 2, 4, 6 months, and every 3 months thereafter. Patients traded time based on their preference for a fixed amount of time in their current state of health (reference period) versus a reduced amount of time in optimal health. The elicitation procedure was framed using three different reference periods - 10-year, 5-year, and 1-year. Mean utilities were evaluated between treatment groups (SRS vs. SRS WBRT), demographic variables, and within subjects over time. Results: The mean age of patients in the trial was 61 years (range 32‐80). Twenty-four patients received SRS and 17 received SRS and WBRT. The majority of patients had lung cancer as their primary tumor (61%) and most had only one metastatic lesion to the brain (68.3%). Of the 43 patients enrolled in the trial, 41 participated in the elicitation exercise. The mean baseline utility over all reference periods was 0.87 and the mean 6-month follow-up utility over all reference periods was 0.82. There were no significant differences in mean utilities from baseline to six-month follow-up between treatment groups or demographic variables. There were significant differences in mean utilities for all patients across different reference periods. Utilities were significantly higher when using the1yr reference period (1yr reference period mean 0.91, 5yr reference period mean 0.88, 10yr reference period mean 0.84; adj. F 4.2, p 0.049). The same effect was observed for one-month follow-up utilities (1yr reference period mean 0.97, 5yr reference period mean 0.87, 10yr reference period mean 0.85; adj. F 5.3, p 0.03). At the one-month follow-up, mean utilities were significantly higher for those receiving SRS without WBRT using the 1yr reference period (SRS group mean 1.0; SRSWBRT group mean 0.93; F 4.7, p 0.042). At the two-month follow-up, mean utilities were significantly higher for patients having their primary tumor site in the lung versus all other primary tumor sites (lung primary mean utilities 0.93, other primary mean utilities 0.71; F 5.0, p 0.037). Conclusions: Utilities for patients in this trial were relatively stable and remained high suggesting reasonable preference for their current health state at the time of elicitation. Most patients did not trade time in their current health state for less time in a more optimal health state when the trade-off was presented with a short 1-year reference period. This utility analysis will provide data needed to perform cost-utility analysis of SRS vs. SRS and WBRT in the future.

Preferences of women facing a prenatal diagnostic choice: long‐term outcomes matter most

Women aged 35 or older who wish to undergo prenatal diagnosis for chromosomal disorders are typically offered a choice between chorionic villus sampling or amniocentesis. These two tests are performed at different times and impose differing miscarriage risks. In deciding which test to use, therefore, women need to consider both short-term consequences (e.g. timing of pregnancy loss, should it occur) and long-term consequences (e.g. whether a pregnancy loss is followed by a future birth). We examined how women seeking prenatal diagnostic services value the outcomes of testing. We conducted a cross-sectional study of 72 women seeking genetic counselling at the University of California at San Francisco or Kaiser San Francisco. We measured preferences for outcomes (utilities) of prenatal diagnosis using the standard gamble metric. We also assessed demographics and attitudes via questionnaire. We observed no differences in mean utilities assigned to first- versus second-trimester pregnancy losses with similar long-term sequelae. Utilities for losses followed by future birth, however, were significantly higher than utilities for losses without future birth (range 0.91 to 0.93 versus 0.84 to 0.86, p<0.05 for all comparisons). In addition, we observed substantial variation in utilities across women. Long-term outcomes matter most to these women. In presenting prenatal diagnostic options to their patients, clinicians should include discussion of outcomes such as the likelihood of future birth in the event of a pregnancy loss. Furthermore, the substantial variation in utilities we observed suggests that future prenatal testing policies should account for the preferences of the individual woman. Copyright © 1999 John Wiley & Sons, Ltd.

Preferences of women facing a prenatal diagnostic choice: long-term outcomes matter most

Women aged 35 or older who wish to undergo prenatal diagnosis for chromosomal disorders are typically offered a choice between chorionic villus sampling or amniocentesis. These two tests are performed at different times and impose differing miscarriage risks. In deciding which test to use, therefore, women need to consider both short-term consequences (e.g. timing of pregnancy loss, should it occur) and long-term consequences (e.g. whether a pregnancy loss is followed by a future birth). We examined how women seeking prenatal diagnostic services value the outcomes of testing. We conducted a cross-sectional study of 72 women seeking genetic counselling at the University of California at San Francisco or Kaiser San Francisco. We measured preferences for outcomes (utilities) of prenatal diagnosis using the standard gamble metric. We also assessed demographics and attitudes via questionnaire. We observed no differences in mean utilities assigned to first- versus second-trimester pregnancy losses with similar long-term sequelae. Utilities for losses followed by future birth, however, were significantly higher than utilities for losses without future birth (range 0.91 to 0.93 versus 0.84 to 0.86, p<0.05 for all comparisons). In addition, we observed substantial variation in utilities across women. Long-term outcomes matter most to these women. In presenting prenatal diagnostic options to their patients, clinicians should include discussion of outcomes such as the likelihood of future birth in the event of a pregnancy loss. Furthermore, the substantial variation in utilities we observed suggests that future prenatal testing policies should account for the preferences of the individual woman.