Time Trade-off Technique Research Articles

PDB72 The Impact on Utilities of Weight Loss and Weight Gain Among Canadian Patients With Type 2 Diabetes

There is evidence in the literature linking weight gain on anti-diabetic medication to impact on psychosocial well-being and non-compliance in type 2 diabetes (T2D). Due to the lack of data on the impact of weight loss and the imminent introduction of a new class of oral agents (SGLT2 inhibitors) with demonstrated weight-loss properties, this study was designed to compare the impact of weight gain and weight loss on utilities among Canadian T2D patients. Health states included a T2D base-case health state and six additional weight change health states (base-case ±3%, ±5%, and ±7% weight change relative to current weight). Utilities were elicited using time trade-off techniques. Enrollment requirements included: having T2D for at least two years, adequate control on antidiabetic medication, not receiving insulin, and not enrolled in a T2D clinical trial. Among 96 respondents (mean age 55 years; 51% male; mean body mass index (BMI) 32 kg/m2) 84% expressed a desire to lose weight. The mean utility (standard error (SE)) for the base-case T2D health state was 0.911 (0.013). The utility decreased to 0.907 (0.013), 0.865 (0.014) and 0.806 (0.017) for the 3%, 5% and 7% weight gain health states, respectively, and increased to 0.923 (0.012), 0.940 (0.011) and 0.949 (0.010) for the 3%, 5% and 7% weight loss health states, respectively. Linear mixed models indicated that a change in weight leading to a one unit increase and decrease in BMI had significant effects (SE) on utilities of -0.0472 (0.005) and 0.0171 (0.003), respectively. We observed a dose-response relationship between weight change and patient-elicited utilities in T2D health states with weight gain having a stronger effect than weight loss. The weight-loss properties of SGLT2 inhibitors may improve utilities while preventing the disutility associated with weight gain, which may positively impact treatment compliance and health outcomes.

Perspectives toward oral mucositis prevention from parents and health care professionals in pediatric cancer

The objectives of this study were: (1) to describe parents and health care professionals (HCPs) perceived importance of oral mucositis prevention in children with cancer; (2) To describe utilities and willingness-to-pay (WTP) to prevent mucositis. Respondents included parents of children receiving intensive chemotherapy for leukemia/lymphoma or undergoing stem cell transplantation and HCPs caring for children with cancer. Importance of mild and severe oral mucositis was estimated using a visual analogue scale (VAS). Mucositis-associated utilities were elicited using the time trade-off technique (TTO). WTP to avoid mucositis was obtained using contingent valuation. These techniques quantify how much time or money the participant is willing to relinquish in order to prevent mucositis. Eighty-two parents and 60 HCPs were included. Parents and HCPs believed mild mucositis to be of similar importance (median VAS 2.5 versus 3.6; P = 0.357) while parents considered severe mucositis less important than HCPs (median VAS 8.3 versus 9.0; P < 0.0001). No differences in parent versus HCP responses were seen with TTO (mild or severe mucositis) and most parents were not willing to trade any survival time to prevent severe mucositis. Parents were willing to pay significantly more than HCPs to prevent mild mucositis (average median WTP $1,371 CAN vs. $684 CAN, P = 0.031). No differences were seen in WTP to prevent severe mucositis. Parents and HCP believe severe mucositis to be important, although it is more important to HCPs. Parents would not be willing to reduce life expectancy to eliminate mucositis.

Psychometric properties of the Oral Mucositis Daily Questionnaire for child self-report and importance of mucositis in children treated with chemotherapy

The objectives of this study were to examine the psychometric properties of the self-report Oral Mucositis Daily Questionnaire (OMDQ) and to measure the importance of mucositis in children receiving intensive chemotherapy. Children ≥ 12 years of age receiving intensive chemotherapy for leukemia/lymphoma or undergoing stem cell transplantation were asked to complete the OMDQ daily for 21 days after chemotherapy. Other measures of mucositis obtained concurrently with OMDQ included the World Health Organization (WHO) mucositis scale, the pain visual analog scale (VAS), and the Functional Assessment of Cancer Therapy Esophageal Cancer Sub-scale (FACT-ECS). The importance of mucositis was estimated using a VAS, time trade-off technique, and willingness to pay to avoid mucositis. Fifteen children participated. Test-retest reliability demonstrated at least moderate correlation for all questions within the OMDQ. Assessment of construct validity of the OMDQ revealed at least moderate correlation with WHO, VAS, and FACT-ECS for questions regarding pain, swallowing, drinking, and eating. Effect on sleeping and talking had lower correlations than that expected a priori. The diarrhea question of the OMDQ did not correlate with other measures of mucositis. Severe mucositis is important to children, while mild mucositis is less important to them. Children were willing to pay moderate amounts of money to prevent mucositis. The OMDQ exhibits test-retest reliability, and most questions show construct validity with the exceptions of the sleep, talking, and diarrhea questions. Therefore, the OMDQ should not be used unmodified as a self-report instrument in children with cancer. Severe mucositis is of importance to these children.

Toward a more universal approach in health valuation

By polling individual responses to hypothetical scenarios, valuation studies estimate population preferences toward health on a quality-adjusted life year (QALY) scale. The scenarios typically involve trade-offs in time (time trade-off (TTO)), risk (standard gamble (SG)), or number of persons affected (person trade-off (PTO)). This paper revisits the QALY assumptions and provides a coherent health econometric approach that unites TTO, SG, and PTO techniques under a common estimator. The proposed approach avoids the use of ratio statistics in QALY estimation and the common convention of arbitrarily changing trade-off responses. As an example, 34% of the TTO responses from the seminal Measurement and Valuation of Health study were changed in the original UK analysis, which led to substantially lower QALY estimates. As a general rule, if the original estimate is less than 0.5 QALYs, add 0.25 QALYs to get the new estimates.

Improving patient access to cancer drugs in India: Using economic modeling to estimate a more affordable drug cost based on measures of societal value

Using multiples of India's per capita gross domestic product (GDP) as the threshold for economic value as suggested by the World Health Organization (WHO), decision analysis modeling was used to estimate a more affordable monthly cost in India for a hypothetical new cancer drug that provides a 3-month survival benefit to Indian patients with metastatic colorectal cancer (mCRC). A decision model was developed to simulate progression-free and overall survival in mCRC patients receiving chemotherapy with and without the new drug. Costs for chemotherapy and side-effects management were obtained from both public and private hospitals in India. Utility estimates measured as quality-adjusted life-years (QALY) were determined by interviewing twenty-four oncology nurses using the Time Trade-Off technique. The monthly cost of the new drug was then estimated using a target threshold of US$9,300 per QALY gained, which is three times the Indian per capita GDP. The base-case analysis suggested that a price of US$98.00 per dose would be considered cost-effective from the Indian public healthcare perspective. If the drug were able to improve patient quality of life above the standard of care or survival from 3 to 6 months, the price per dose could increase to US$170 and US$253 and offer the same value. The use of the WHO criteria for estimating the cost of a new drug based on economic value for a developing country like India is feasible and can be used to estimate a more affordable cost based on societal value thresholds.

Are patients' judgments of health status really different from the general population?

BackgroundMany studies have found discrepancies in valuations for health states between the general population (healthy people) and people who actually experience illness (patients). Such differences may be explained by referring to various cognitive mechanisms. However, more likely most of these observed differences may be attributable to the methods used to measure these health states. We explored in an experimental setting whether such discrepancies in values for health states exist. It was hypothesized that the more the measurement strategy was incorporated in measurement theory, the more similar the responses of patients and healthy people would be.MethodsA sample of the general population and two patient groups (cancer, rheumatoid arthritis) were included. All three study groups judged the same 17 hypothetical EQ-5D health states, each state comprising the same five health domains. The patients did not know that apart from these 17 states their own health status was also included in the set of states they were assessing. Three different measurement strategies were applied: 1) ranking of the health states; 2) placing all the health states simultaneously on a visual analogue scale (VAS); 3) separately assessing the health states with the time trade-off (TTO) technique. Regression analyses were performed to determine whether differences in the VAS and TTO can be ascribed to specific health domains. In addition, effect of being member of one of the two patient groups and the effect of the assessment of the patients' own health status was analyzed.ResultsExcept for some moderate divergence, no differences were found between patients and healthy people for the ranking task or for the VAS. For the time trade-off technique, however, large differences were observed between patients and healthy people. The regression analyses for the effect of belonging to one of the patient groups and the effect of the value assigned to the patients' own health state showed that only for the TTO these patient-specific parameters did offer some additional information in explaining the 17 hypothetical EQ-5D states.ConclusionsPatients' assessment of health states is similar to that of the general population when the judgments are made under conditions that are defended by modern measurement theory.

Emerging Ideas: Shared Decision Making in Patients with Osteoarthritis of the Hip and Knee

BackgroundDespite the widely reported success of total joint arthroplasty (TJA) in reducing pain and improving quality of life and function for patients with hip or knee osteoarthritis, rates of TJA use vary widely throughout the United States, with broad disparities based on geographic, racial, and socioeconomic factors. Shared decision-making approaches, which require an exchange of information between patients and their physicians, can be helpful in improving patient satisfaction with their treatment decision and appropriate use of TJA.Questions/hypothesesExpected-value decision analysis models incorporating evidence-based outcome data with individual patient preferences regarding health states and willingness to pay, when used in shared decision-making models, will improve satisfaction among patients with hip or knee osteoarthritis and lead to more appropriate use of TJA.Proposed ProgramPatients with hip or knee osteoarthritis will be randomized to usual care or participation in a shared decision-making intervention. Patients in the shared decision-making intervention arm will have their preferences for individual health states related to osteoarthritis and TJA measured using the time trade-off technique, and these values will be incorporated in an expected-value decision analysis model, which also will incorporate the patient’s willingness to pay for a particular treatment intervention and evidence-based outcome probabilities. The patient’s decision for operative versus nonoperative care and their level of satisfaction with their decision will be compared using chi square and Mann-Whitney rank-sum tests.SignificanceInformation regarding patient preferences for particular health states and willingness to pay can be combined with evidence-based outcome data in expected-value decision analysis models, which will help inform shared clinical decision making between surgeons and their patients with hip or knee osteoarthritis.

Predicting Time Trade-Off Health State Valuations of Adolescents in Four Pacific Countries Using the Assessment of Quality-of-Life (AQoL-6D) Instrument

Objectives Pacific Obesity Prevention in Communities (OPIC) is a community-based intervention project targeting adolescent obesity in Australia, New Zealand, Fiji, and Tonga. The Assessment of Quality of Life Mark 2 (AQoL-6D) instrument was completed by 15,481 adolescents to obtain a description of the quality of life associated with adolescent overweight and obesity, and a corresponding utility score for use in a cost–utility analysis of the interventions. This article describes the recalibration of this utility instrument for adolescents in each country. Methods The recalibration was based on country-specific time trade-off (TTO) data for 30 multiattribute health states constructed from the AQoL-6D descriptive system. Senior secondary students, in a classroom setting, responded to 10 health state scenarios each. These TTO interviews were conducted for 24 groups, comprising 279 students in the four countries resulting in 2790 completed TTO scores. The TTO scores were econometrically transformed by regressing the TTO scores upon predicted scores from the AQoL-6D to produce country-specific algorithms. The latter incorporated country-specific “corrections” to the Australian adult utility weights in the original AQoL. Results This article reports two methodological elements not previously reported. The first is the econometric modification of an extant multi-attribute utility instrument to accommodate cultural and other group-specific differences in preferences. The second is the use of the TTO technique with adolescents in a classroom group setting. Significant differences in utility scores were found between the four countries. Conclusion Statistical results indicate that the AQoL-6D can be validly used in the economic evaluation of both the OPIC interventions and other adolescent programs.

Test-retest reliability of health state valuation techniques: the time trade off and person trade off

Economic analysis is increasingly being employed in formal resource allocation decision-making processes in health care. As a consequence, the methods employed by economic analysts are increasingly subject to close scrutiny. One such area of methodology concerns the instruments used to elicit preferences for various health states for use in the construction of quality-adjusted life years. There are a number of techniques which may be used to elicit preferences and different techniques produce different results. The objective of this study was to explore the test-retest reliability of two techniques: Time Trade Off (TTO) and Person Trade Off (PTO) valuations were collected by a general population postal survey. A total of 798 respondents returned questionnaires. The intra class correlation coefficients ranged from 0.40 to 0.88 for TTO and, -0.17 to 0.82 for PTO, with the majority of coefficients being >0.50. The reliability coefficients varied between techniques and health states, with the TTO technique tending to produce higher coefficients. While the reliability results for TTO were generally positive, the reliability results for PTO are less clear.

Estimating a Preference-Based Index for a 5-Dimensional Health State Classification for Asthma Derived from the Asthma Quality of Life Questionnaire

This article presents a valuation study to estimate a preference-based index for a 5-dimensional health state classification for asthma (AQL-5D) derived from the Asthma Quality of Life Questionnaire (AQLQ). A sample of 307 members of the UK general population valued 99 asthma health states selected from the AQL-5D using the time tradeoff technique. Models were estimated to predict all possible 3125 health states defined by the AQL-5D, and the models were compared in terms of their ability to predict mean values for the 99 states. Mean health state values ranged from 0.39 to 0.94 based on an average of 22 valuations per state. A main effects model estimated on mean health state values and adjusted for consistency had the best predictive ability (mean absolute error of 0.047 and only 9/98 states with errors >0.1) and the most logical consistency with levels of the AQL-5D. The low number of valuations per state may have resulted in unreliable estimates for the models. Preference-based condition specific measures are limited in their ability to make cross-disease comparisons. This is the first study to derive a condition-specific preference-based measure from an existing measure of health-related quality of life in asthma for use in economic evaluation.

Early versus delayed bilateral subthalamic deep brain stimulation for parkinson's disease: A decision analysis

The long-term benefits of subthalamic nucleus deep brain stimulation (STN DBS) applied earlier in the disease course, before significant disability accumulates, remain to be determined. We developed a Markov state transition decision analytic model to compare effectiveness in quality-adjusted life years (QALYs) of STN DBS applied to patients with PD at an "early" ("off time" 10-20%) versus "delayed" stage ("off time" >40%). A lifelong time horizon and societal perspective were assumed. Probabilities and rates were obtained from literature review; utilities were derived using the time trade-off technique and a computer-assisted utility assessment software tool applied to a cohort of 22 STN-DBS and 21 non-STN-DBS PD patients. Uncertainty was assessed through one- and two-way sensitivity analyses and probabilistic sensitivity analysis using second-order Monte Carlo simulations. Early STN DBS was preferred with a quality-adjusted life expectancy of 22.3 QALYs, a gain of 2.5 QALYs over those with delayed surgery (19.8 QALYs). Early STN DBS was preferred in 69% of 5,000 Monte Carlo simulations. Early surgery was robustly favored through most sensitivity analyses. Delayed STN DBS afforded greater QALYs when using utility estimates exclusively from non-STN-DBS patients and, for the entire group, if the rate of motor progression were to exceed 25% per year. Although decision modeling requires assumptions and simplifications, our exploratory analysis suggests that STN DBS performed in early PD may convey greater quality-adjusted life expectancy when compared to a delayed procedure. These findings support further evaluation of early STN DBS in a controlled clinical trial.

A Time Tradeoff Method for Eliciting Partner’s Quality of Life due to Patient’s Health States in Prostate Cancer

Cost-effectiveness analyses may better reflect the full costs and benefits of medical interventions if they incorporate the effects of patients' health on their family members. To develop and apply a time tradeoff (TTO) technique to measure the impact of potential prostate cancer-related health states of the patients on the quality of life (QOL) of their partners. We developed modified TTO questions and applied them in a pilot study in which we asked the partner of the patient to tradeoff his or her own life in order to reduce the burden that he himself or she herself expects to experience if the patient developed one of the prostate cancer-related health states. We reviewed the theoretical justification for this question and carefully framed the question so as to reduce measurement error and also to avoid possible double counting with the effect on the partner's health. We collected data from 26 partners about their preferences for their own health, which is influenced by the patient's health condition. The mean QOL weights for the partners when the patients are the following states are healthy, 0.81; impotent, 0.66; incontinent, 0.68; have metastatic disease, 0.50; and dead, 0.28. Partners' responses varied by how close they felt to the patients. Low correlations between partners' and patients' QOL ratings (n = 15) suggest that the partners were not responding as proxies for the patient. A new TTO method is proposed to measure a partner's QOL due to a patient's health. Preliminary test results of validity were promising.

A comparison of United States and United Kingdom EQ‐5D health states valuations using a nonparametric Bayesian method

Cost-effectiveness analysis of alternative medical treatments relies on having a measure of effectiveness, and many regard the quality adjusted life year (QALY) to be the current 'gold standard.' In order to compute QALYs, we require a suitable system for describing a person's health state, and a utility measure to value the quality of life associated with each possible state. There are a number of different health state descriptive systems, and we focus here on one known as the EQ-5D. Data for estimating utilities for different health states have a number of features that mean care is necessary in statistical modelling.There is interest in the extent to which valuations of health may differ between different countries and cultures, but few studies have compared preference values of health states obtained from different countries. This article applies a nonparametric model to estimate and compare EQ-5D health state valuation data obtained from two countries using Bayesian methods. The data set is the US and UK EQ-5D valuation studies where a sample of 42 states defined by the EQ-5D was valued by representative samples of the general population from each country using the time trade-off technique. We estimate a utility function across both countries which explicitly accounts for the differences between them, and is estimated using the data from both countries. The article discusses the implications of these results for future applications of the EQ-5D and for further work in this field.

Preference values associated with stage III colon cancer and adjuvant chemotherapy

To elicit preference values for health states associated with Stage III colon cancer (CRC) and to explore the effect of neuropathy associated with current adjuvant treatment. We used time trade-off (TTO) techniques to elicit preferences from 49 CRC patients and 49 community members. We elicited preferences for 7 health states: remission; adjuvant therapy with no, mild, moderate, and severe neuropathy; metastatic stable; and metastatic progressive disease. Mean TTO values were adjusted for the covariates age, education, and current health. Patients' adjusted mean TTO value for remission was 0.83; adjuvant chemotherapy health states ranged from 0.48 to 0.61. Significant differences were observed for both patient and community groups between TTO for remission and all adjuvant health states (P < 0.001), and between adjuvant therapy with no neuropathy and metastatic health states (P < or = 0.001). Across all health states, patients' values were on average 0.12 higher than community members (P < 0.05). The findings highlight the trade-offs between the disutility of adjuvant treatment, the higher utility of remission, and the severe utility loss during metastatic disease. The preference values obtained from this study will be useful for informing patients' treatment decisions and payer cost-utility analyses of adjuvant treatment for colon cancer.

Utility assessment among patients of primary angle closure/glaucoma in China: a preliminary study

Aim:To evaluate utility values among patients of primary angle closure/glaucoma (PAC/G) in a local hospital in China, and the factors influencing the quality of their lives.Methods:A cross-sectional study. Utility values...

Utility Weights for Allergic Rhinitis Based on a Community Survey with a Time Trade-off Technique in Japan

Allergic rhinitis is not a fatal disease, but its symptoms deteriorate the quality of life. High morbidity raises a concern about its impact on health care resources. Utility weights, which are required for cost-utility analysis by the level of severity, have not been established to date. This study aims to derive the weights based on a community survey with a time trade-off technique. Self-administered monthly time trade-off questionnaires were administered to representative samples in the community. Four levels of severity were defined by clinical stratification proposed in the "Practical Guideline for the Management of Allergic Rhinitis in Japan". 146 responses (response rate: 51.0%) were collected. Utility weights by the four levels of severity were found to be 0.96, 0.94, 0.89 and 0.83, from mild to severest symptoms, respectively. These values were found to be statistically independent from the respondent's characteristics such as sex, age, existence of current nasal symptoms or history of allergic rhinitis. The authors consider that the elicited utility weights are reliable. The results of this study could facilitate economic evaluations regarding allergic rhinitis in various contexts, contributing to better management of the disease.

Extended Dalteparin Prophylaxis for Venous Thromboembolic Events

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are manifestations of venous thromboembolic events (VTEs). Patients undergoing major surgical procedures such as total hip replacement (THR), total knee replacement (TKR), and hip fracture surgery (HFS) are at an elevated risk for VTEs. The American College of Chest Physicians’ (ACCP) guidelines recommend that such patients receive thromboprophylaxis for at least 10 days. In patients undergoing THR or HFS, extended prophylaxis for up to 28–35 days is the recommended approach for those at high risk of thromboembolic events. The NAFT (North American Fragmin Trial) compared the prophylactic efficacy of dalteparin with that of warfarin during the in-hospital period, and with that of placebo during the period of hospital discharge until day 35 postsurgery, in patients who underwent total hip arthroplasty. During both the in-hospital and the post-discharge time periods, dalteparin significantly reduced the occurrence of DVT. Given the clinical relevance of these results, the low specificity of the ACCP recommendations regarding optimal prophylaxis duration, and the importance of optimizing the efficiency of DVT prophylaxis in the practice setting, a cost-utility analysis was conducted comparing dalteparin 10-day and 35-day (extended) with a warfarin 10-day protocol, in patients undergoing major orthopedic surgeries such as THR, TKR, or HFS. A three-arm decision model was developed using the prevalence of symptomatic DVT from NAFT publications, epidemiologic studies, and published meta-analyses. Healthcare resource use was abstracted from a survey of clinicians and from the economic literature. Utility estimates were obtained by interviewing a sample of 24 people from the general public using the time trade-off technique. The clinical, economic and utility data were then used to estimate the cost per quality-adjusted life-year (QALY) gained with dalteparin for 10 or 35 days relative to 10 days of warfarin. Canadian provincial healthcare system. The cost per QALY gained with 10 days of dalteparin was below $Can1000 for all the surgeries evaluated (all costs are reported in 2007 Canadian dollars [$Can1 = $US1, as of December 2007]). In the case of extended prophylaxis, the incremental cost per QALY gained with 35 days of dalteparin over warfarin was $Can40 100, $Can46 500, and $Can31 200 for patients undergoing THR, TKR, and HFS, respectively. Reducing the duration of prophylaxis from 35 to 28 days generated ratios that were below $Can35 000 for all three surgeries evaluated. Ten days of dalteparin following major orthopedic surgery is a clinically and economically attractive alternative to warfarin for DVT prophylaxis. In the case of the 35-day dalteparin protocol, the results also indicated acceptable economic value to a publicly funded healthcare system, particularly in the settings of HFS and THR. In addition, reducing the duration of prophylaxis to 28 days postsurgery would be associated with a more favorable return on public healthcare expenditures.

Cost-effectiveness of pentostatin compared with cladribine in the management of hairy cell leukemia in the United Kingdom

Objective: This article assesses the cost-effectiveness of pentostatin compared with cladribine in the management of hairy cell leukemia (HCL) in the United Kingdom. Methods: A systematic literature search for papers on HCL was performed using MEDLINE, EMBASE, Current Contents, NHS Economic Evaluation Database, and the Cochrane computerized database. Search terms were HCL plus 1 of the following: incidence, prevalence, epidemiology, cladribine, interferon, pentostatin, rituximab, splenectomy, utility, quality of life, cost-effectiveness, cost-utility, resource utilization, economic, or cost. Published clinical outcomes and estimates of health care resource use obtained from 10 consultant hematologists across the United Kingdom were used to construct a 5-year Markov model depicting the current management of HCL in the United Kingdom. Utilities for health states in the model were obtained from the general public using standard gamble, time tradeoff, and visual analog scale techniques. The model was used to consider the decision by a clinician to initially treat an HCL patient with either pentostatin or cladribine and to estimate the relative cost-effectiveness of pentostatin over 5 years (at 2007/2008 prices) from the perspective of the UK's National Health Service (NHS). Results: According to the model, 64% of all pentostatin-treated patients are expected to be in relapse-free remission at 5 years compared with 49% of cladribine-treated patients ( P = 0.04). Repeat treatment of initial partial responders, nonresponders, and those who relapse during the 5 years is expected to result in complete remission in 92% of pentostatintreated patients and 90% of cladribine-treated patients at 5 years. Using pentostatin instead of cladribine is expected to lead to a minimal cost increase (from £21,325 to £21,609) and an improvement in health status (from 3.64 to 3.77 quality-adjusted life-years [QALYs]) over 5 years. Hence, the cost per QALY gained from using pentostatin is expected to be £5000. Moreover, pentostatin has a 0.90 probability of being cost-effective for a threshold of £20,000 per QALY. Accordingly, using pentostatin as a first-line treatment for patients with HCL is an effective use of NHS resources. Conclusion: Based on current practice, this model predicts that pentostatin is a cost-effective treatment compared with cladribine in the management of HCL from the perspective of the UK's NHS.

Factors Associated with Variation in Utility Scores among Patients with Prostate Cancer

Objective We aimed to assess the effects of age, comorbidity, and disease-specific functions on utility scores derived from three methods on prostate cancer. Methods A total of 330 Japanese prostate cancer patients were asked to answer self-administered questionnaires. Community-weighted utility scores were derived from the EuroQoL-5D (EQ-5D) and the Short Form-36 (SF-36), while the patient's directly elicited utility score was derived from time trade-off technique. Univariate and multivariate analyses were performed to examine the relation between covariates and utility scores. We assigned age, the Index of Co-existent Disease, and disease-specific functions including sexual, urinary, bowel, and hormonal function as covariates. Results Bowel and hormonal function were related to utility scores, while age and sexual function were not. Comorbidities were more closely related to utility scores derived from EQ-5D and SF-36. Conclusions These results contribute to an understanding of which factor has an impact on utility scores in patients with prostate cancer.

Disability Adjusted Life Years and minimal disease: application of a preference-based relevance criterion to rank enteric pathogens

BackgroundBurden of disease estimates, which combine mortality and morbidity into a single measure, are used increasingly for priority setting in disease control, prevention and surveillance. However, because there is no clear exclusion criterion for highly prevalent minimal disease in burden of disease studies its application may be restricted. The aim of this study was to apply a newly developed relevance criterion based on preferences of a population panel, and to compare burden of disease estimates of five foodborne pathogens calculated with and without application of this criterion.MethodsPreferences for twenty health states associated with foodborne disease were obtained from a population panel (n = 107) with the Visual Analogue Scale and the Time Trade-off (TTO) technique. The TTO preferences were used to derive the relevance criterion: if at least 50% of a panel of judges is willing to trade-off time in order to be restored to full health the health state is regarded as relevant, i.e. TTO median is greater than 0. Subsequently, the burden of disease of each of the five foodborne pathogens was calculated both with and without the relevance criterion.ResultsThe panel ranked the health states consistently. Of the twenty health states, three did not meet the preference-based relevance criterion. Application of the relevance criterion reduced the burden of disease estimate of all five foodborne pathogens. The reduction was especially significant for norovirus and rotavirus, decreasing with 94% and 78% respectively.ConclusionIndividual preferences elicited with the TTO from a population panel can be used to empirically derive a relevance criterion for burden of disease estimates. Application of this preference-based relevance criterion results in considerable changes in ranking of foodborne pathogens.