Incorporating utility-based quality-of-life assessment measures in clinical trials. Two examples

The Use of Generic Patient-Reported Outcome Measures in Emergency Department Surveys: Discriminant Validity Evidence for the Veterans RAND 12-Item Health Survey and the EQ-5D

OBJECTIVES

This study aimed to compare discriminant validity evidence of 2 generic patient-reported outcome measures (PROMs), the Veterans RAND 12-Item Health Survey (VR-12) and level 5 of EQ-5D (EQ-5D-5L), for use in emergency departments (EDs).

METHODS

Data were obtained via a cross-sectional survey of 5876 patients in British Columbia (Canada) who completed a questionnaire after visiting an ED in 2018. We compared the extent to which the VR-12 and the EQ-5D-5L distinguished among groups of ED patients with different levels of comorbidity burden and self-reported physical and mental or emotional health status. Multivariable logistic regression was used to evaluate the ability of the 2 PROMs to identify patients presenting with a mental health (MH) condition.

RESULTS

All the measures produced small effect sizes (ESs) for discriminating comorbidity levels (R² range: 0.00 [VR-12 mental component summary {MCS}] to 0.10 [VR-12 physical component summary score]). The EQ-5D visual analog scale offered the largest ES for discriminating self-reported physical health (R² = 0.48), whereas the MCS, the VR-12 MH domain, and the EQ-5D-5L anxiety/depression dimension had the largest ESs for discriminating self-reported mental or emotional health (R² = 0.42, 0.40, and 0.38, respectively). The MCS produced a medium ES (R² = 0.42) along with the VR-12 utility score (R² = 0.27) compared with the EQ-5D-5L index (R² = 0.19). Having a MH condition was predominantly identified by the MCS (Pratt index = 0.56).

CONCLUSIONS

The VR-12 PROM provides a more comprehensive measurement of MH than the EQ-5D-5L, which is important to inform healthcare service needs for patients who present in EDs with MH challenges.

Cross-sectional validation of the PROMIS-Preference scoring system by its association with social determinants of health

PURPOSE

PROMIS-Preference (PROPr) is a generic, societal, preference-based summary score that uses seven domains from the Patient-Reported Outcomes Measurement Information System (PROMIS). This report evaluates construct validity of PROPr by its association with social determinants of health (SDoH).

METHODS

An online panel survey of the US adult population included PROPr, SDoH, demographics, chronic conditions, and four other scores: the EuroQol-5D-5L (EQ-5D-5L), Health Utilities Index (HUI) Mark 2 and Mark 3, and the Short Form-6D (SF-6D). Each score was regressed on age, gender, health conditions, and a single SDoH. The SDoH coefficient represents the strength of its association to PROPr and was used to assess known-groups validity. Convergent validity was evaluated using Pearson correlations between different summary scores and Spearman correlations between SDoH coefficients from different summary scores.

RESULTS

From 4142 participants, all summary scores had statistically significant differences for variables related to education, income, food and financial insecurity, and social interactions. Of the 42 SDoH variables tested, the number of statistically significant variables was 27 for EQ-5D-5L, 17 for HUI Mark 2, 23 for HUI Mark 3, 27 for PROPr, and 27 for SF-6D. The average SDoH coefficients were - 0.086 for EQ-5D-5L, - 0.039 for HUI Mark 2, - 0.063 for HUI Mark 3, - 0.064 for PROPr, and - 0.037 for SF-6D. Despite the difference in magnitude across the measures, Pearson correlations were 0.60 to 0.76 and Spearman correlations were 0.74 to 0.87.

CONCLUSIONS

These results provide evidence of construct validity supporting the use of PROPr monitor population health in the general US population.

Measuring upper limb disability for patients with neck pain: Evaluation of the feasibility of the single arm military press (SAMP) test

BACKGROUND

Non-specific neck pain (NSNP) is frequently associated with upper limb disability (ULD). Consequently, evaluation of ULD using an outcome measure is necessary during the management of patients with NSNP. The Single Arm Military Press (SAMP) test is a performance-based ULD measure developed for populations with neck pain. During the SAMP test, patients are asked to repeatedly lift a weight above their head for 30 s. The number of repetitions is counted. Its clinical utility in a patient group is still unknown.

OBJECTIVE

This study investigates the feasibility of the SAMP test from patients and clinicians' perspectives.

METHODS

Seventy female patients with NSNP were randomly allocated into one of three groups. Participants in each group completed the SAMP test using one of three proposed weights (½kg, 1 kg or 1½kg). The feasibility of the SAMP test was established using structured qualitative exit feedback interviews for patients and administrating clinicians.

RESULTS

Participants using ½kg achieved the highest number of repetitions, but a high proportion reported the weight as extremely light, whereas those who tested using the 1½kg achieved the lowest number of repetitions and participants reported the weight as being heavy. Participants tested using 1 kg achieved an average number of repetitions and a high proportion reported the weight as acceptably heavy. Clinicians and patients reported that the SAMP test was efficient and convenient.

CONCLUSION

The 1 kg SAMP test is feasible for use in female patients with NSNP. The measurement properties of the SAMP test should be determined in a patient group.

Comparing the Noncomparable: The Need for Equivalence Measures That Make Sense in Health-Economic Evaluations

BACKGROUND

The popularity of quality-adjusted life years (QALYs) has been resistant to concerns about validity and reliability. Utility-theoretic outcome equivalents are widely used in other areas of applied economics. Equivalence values can be derived for time, money, risk, and other metrics. These equivalence measures preserve all available information about individual preferences and are valid measures of individual welfare changes.

OBJECTIVE

The objective of this study was to derive alternative generalized equivalence measures from first principles and illustrate their application in an empirical comparative-effectiveness example.

METHODS

We specify a general-equilibrium model incorporating neoclassical utility functions, health production function, severity-duration preferences, and labor-market tradeoff function. The empirical implementation takes advantage of discrete-choice experiment methods that are widely accepted in other areas of applied economics and increasingly in health economics. We illustrate the practical significance of restrictive QALY assumptions using comparative-effectiveness results based on both QALYs and estimates of welfare-theoretic time-equivalent values for anti-tumor necrosis factor and prolonged corticosteroid treatments for Crohn's disease in three distinct preference classes.

RESULTS

The QALY difference between the two treatments is 0.2 months, while time-equivalent values range between 0.5 and 1.3 months for aggregate and class-specific differences. Thus, the QALY-based analysis understates welfare-theoretic values by 60%-85%.

CONCLUSION

These results suggest that using disease-specific equivalence values offer a meaningful alternative to QALYs to compare global outcomes across treatments. The equivalence values approach is consistent with principles of welfare economics and offers several features not represented in QALYs, including accounting for preference nonlinearities in disease severity and duration, inclusion of preference-relevant nonclinical healthcare factors, representing preferences of clinically-relevant patient subpopulations, and including utility losses related to risk aversion.

Utility analysis and calibration of QOL assessment in disease management

In clinical trials, the assessment of health-related quality of life (QOL) (or patient-reported outcome [PRO] measure) has become very popular especially for clinical studies conducted for evaluating clinical benefits of patients with chronic, severe, and/or life threatening diseases. Health-related QOL information and PRO measures are useful for disease management for achieving best clinical practice. In this article, we will focus on health-related QOL assessment. The concept, design, and analysis of health-related QOL in clinical trials are reviewed. Validation of the use of health-related QOL instrument in terms of some key performance characteristics such as accuracy, reliability, sensitivity, and responsibility for assuring quality, integrity, and validity of collected QOL data are discussed. The concept of utility analysis and calibration (e.g., with respect to life events) for achieving the optimization of disease management are proposed. The change of the QOL could be translated into different life events for effective disease management. These translations could evaluate the treatment effect by more directly displaying the change of the QOL.

Understanding United States Investigational Device Exemption Studies-Clinical Relevance and Importance for Healthcare Economics

INTRODUCTION

The US Food and Drug Administration allows a previously unapproved device to be used clinically to collect safety and effectiveness data under their Investigational Device Exemption (IDE) category. The process usually falls under 3 different trial categories: noninferiority, equivalency, and superiority. To confidently inform our patients, understanding the basic concepts of these trials is paramount. The purpose of this manuscript was to provide a comprehensive review of these topics using recently published IDE trials and economic analyses of cervical total disc replacement as illustrative examples.

CASE STUDY MOBI-C ARTIFICIAL CERVICAL DISC

In 2006, an IDE was initiated to study the safety and effectiveness of total disc replacement controlled against the standard of care, anterior cervical discectomy, and fusion. Under the IDE, randomized controlled trials comparing both 1 and 2 level cervical disease were completed. The sponsor designed the initial trial as noninferiority; however, using adaptive methodology, superiority could be claimed in the 2-level investigation.

REVIEWING HEALTHCARE ECONOMICS

Healthcare economics are critical in medical decision making and reimbursement practices. Once both cost- and quality-adjusted life-year (QALY) are known for each patient, the incremental cost-effectiveness ratio is calculated. Willingness-to-pay is controversial, but a commonly cited guideline considers interventions costing below 20 000 $/QALY strongly cost effective and more than 100 000 $/QALY as not cost effective.

CONCLUSION

While large Food and Drug Administration IDE studies are often besieged by complex statistical considerations and calculations, it is fundamentally important that clinicians understand at least the terminology and basic concepts on a practical level.

Quantifying Worry in the Face of Uncertainty: Radiation Exposure from Medical Imaging

BACKGROUND

The degree to which people worry about radiation exposure from medical imaging has not been quantified. Such concern is important for clinical decision making and policy generation.

OBJECTIVE

The aim of this study was to quantify the degree of worry as a consequence of radiation exposure.

DESIGN

A time trade-off methodology was used to estimate health state utilities associated with radiation exposure from computed tomography scans in an inclusive sample of physicians. Health state utilities were elicited from in-person interviews using a software-guided, hypothetical scenario in which the subject is exposed to two separate computed tomography scans.

RESULTS

One hundred and eighteen interviews were conducted. The overall mean and median utility values for the health state of concern due to radiation exposure were 0.95 (95% confidence interval: 0.94-0.96) and 0.98 (interquartile range: 0.91-1.00), respectively. The utility score distribution was highly skewed toward higher values. Five respondents (4.3%) recorded a utility score of ≤0.8 and 17 respondents (14.5%) were willing to sacrifice at least 5 or more years of life to live free of the radiation-exposure worry.

CONCLUSIONS AND RELEVANCE

The physician respondents generally demonstrated low levels of disutility; however, a subset of physicians expressed much greater disutility for the future risk of malignancy. Given the potential for physicians to influence health care decisions and policies, further study of radiation-related concerns seems warranted. Physicians, patients, and the general public should be aware of the potential impact such differing views held by physicians may have on their clinical recommendations.

Longitudinal change in quality of life following hospitalisation for acute exacerbations of COPD

Background

Current guidelines for management of patients hospitalised with acute exacerbations of chronic obstructive pulmonary disease (COPD) recommend that clinical decisions, including escalation to assisted ventilation, be informed by an estimate of the patients’ likely postdischarge quality of life. There is little evidence to inform predictions of outcome in terms of quality of life, psychological well-being and functional status. Undue nihilism might lead to denial of potentially life-saving therapy, while undue optimism might prolong suffering when alternative palliation would be more appropriate. This study aimed to detail longitudinal changes in quality of life following hospitalisation for acute exacerbations of COPD.

Methods

We prospectively recruited two cohorts (exacerbations requiring assisted ventilation during admission and exacerbations not ventilated). Admission clinical data, and mortality and readmission details were collected. Quality of life, psychological well-being and functional status were formally assessed over the subsequent 12 months. Time-adjusted mean change in quality of life was examined.

Results

183 patients (82 ventilated; 101 not ventilated) were recruited. On average, overall quality of life improved by a clinically important amount in those not ventilated and did not decline in ventilated patients. Both groups showed clinically important improvements in respiratory symptoms and an individual's sense of control over their condition, despite the tendency for functional status to decline.

Conclusions

On average, postdischarge quality of life improved in non-ventilated and did not decline in ventilated patients. Certain quality of life domains (ie, symptoms and mastery) improved significantly. Better understanding of longitudinal change in postdischarge quality of life should help to inform decision-making.

Health impact and economic analysis of NGO-supported neurosurgery in Bolivia

OBJECT

Bolivia, one of the poorest countries in the world, ranks 108th on the 2013 Human Development Index. With approximately 1 neurosurgeon per 200,000 people, access to neurosurgery in Bolivia is a growing health concern. Furthermore, neurosurgery in nonindustrialized countries has been considered both cost-prohibitive and lacking in outcomes evaluation. A non-governmental organization (NGO) supports spinal procedures in Bolivia (Solidarity Bridge), and the authors sought to determine its impact and cost-effectiveness.

METHODS

In a retrospective review of prospectively collected data, 19 patients were identified prior to spinal instrumentation and followed over 12 months. For inclusion, patients required interviewing prior to surgery and during at least 2 follow-up visits. All causes of spinal pathology were included. Sixteen patients met inclusion criteria and were therefore part of the analysis. Outcomes measured included assessment of activities of daily living, pain, ambulation, return to work/school, and satisfaction. Cost-effectiveness was determined by cost-utility analysis. Utilities were derived using the Health Utilities Index. Complications were incorporated into an expected value decision tree.

RESULTS

Median (± SD) preoperative satisfaction was 2.0 ± 0.3 (on a scale of 0-10), while 6-month postoperative satisfaction was 7 ± 1.4 (p < 0.0001). Ambulation, pain, and emotional disability data suggested marked improvement (56%, 69%, and 63%, respectively; p = 0.035, 0.003, and 0.006). Total discounted incremental quality-adjusted life year (QALY) gain was 0.771. The total discounted cost equaled $9036 (95% CI $8561-$10,740) at 2 years. Computing the incremental cost-effectiveness ratio resulted in a value of $11,720/QALY, ranging from $9220 to $15,473/QALY in a univariate sensitivity analysis.

CONCLUSIONS

This NGO-supported spinal instrumentation program in Bolivia appears to be cost-effective, especially when compared with the conventional $50,000/QALY benchmark and the WHO endorsed country-specific threshold of $16,026/QALY. However, with a gross domestic product per capita in Bolivia equaling $4800 per year and 30.3% of the population living on less than $2 per day, this cost continues to appear unrealistic. Additionally, the study has several significant limitations, namely its limited sample size, follow-up period, the assumption that patients not receiving surgical intervention would not make any clinical improvement, the reliance on the NGO for patient selection and sustainable practices such as follow-up care and ancillary services, and the lack of a randomized prospective design. These limitations, as well as an unclear understanding of Bolivian willingness-to-pay data, affect the generalizability of the study findings and impede widespread economic policy reform. Because cost-effectiveness research may inevitably direct care decisions and prove that an effort such as this can be cost saving, a prospective, properly controlled investigation is now warranted.

Using existing data to identify candidate items for a health state classification system in multiple sclerosis

PURPOSE

In multiple sclerosis (MS), the use of preference-based measures is limited to generic measures such as Health Utilities Index Mark 2 and 3, the EQ-5D and the SF-6D. However, the challenge of using such generic preference-based measures in people with MS is that they may not capture all domains of health relevant to the disease. Therefore, the main aim of this paper is to describe the development of a health state classification system for MS patients. The specific objectives are: (1) to identify items best reflecting the domains of quality of life important to people with MS and (2) to provide evidence for the discriminative capacity of the response options by cross-walking onto a visual analog scale of health rating.

METHODS

The data come from an epidemiologically sampled population of people with MS diagnosed post-1994. The dataset consisted of 206 items relating to impairments, activity limitations, participation restrictions, health perception and quality of life. Important domains were identified from the responses to the Patient Generated Index, an individualized measure of quality of life. The extent to which the items formed a uni-dimensional, linear construct was estimated using Rasch analysis, and the best item was selected using the threshold map.

RESULTS

The sample was young (mean age 43) and predominantly female (n = 140/189; 74%). The P-PBMSI classification system consisted of five items, with three response levels per item, producing a total of 243 possible health states. Regression coefficient values consistently decreased between response levels and the linear test for trend were statistically significant for all items. The linear test for trend indicated that for each item the response options provided the same discriminative ability within the magnitude of their capacity. A scoring algorithm was estimated using a simple additive formula. The classification system demonstrated convergent validity against other measures of similar constructs and known-groups validity between different clinical subgroups.

CONCLUSION

This study produced a health state classifier system based on items impacted upon by MS, and demonstrated the potential to discriminate the health impact of the disease.

Standardizing cost-utility analysis in neurosurgery

This review seeks to introduce the concept of cost-utility analysis in neurosurgery and to highlight its essential components. It also includes a suggested approach to standardization, which would help bring more credence to this research and potentially affect management choices, reimbursement, and policy.

Do generic utility measures capture what is important to the quality of life of people with multiple sclerosis?

PURPOSE

The three most widely used utility measures are the Health Utilities Index Mark 2 and 3 (HUI2 and HUI3), the EuroQol-5D (EQ-5D) and the Short-Form-6D (SF-6D). In line with guidelines for economic evaluation from agencies such as the National Institute for Health and Clinical Excellence (NICE) and the Canadian Agency for Drugs and Technologies in Health (CADTH), these measures are currently being used to evaluate the cost-effectiveness of different interventions in MS. However, the challenge of using such measures in people with a specific health condition, such as MS, is that they may not capture all of the domains that are impacted upon by the condition. If important domains are missing from the generic measures, the value derived will be higher than the real impact creating invalid comparisons across interventions and populations. Therefore, the objective of this study is to estimate the extent to which generic utility measures capture important domains that are affected by MS.

METHODS

The available study population consisted of men and women who had been registered after 1994 in three participating MS clinics in Greater Montreal, Quebec, Canada. Subjects were first interviewed on an individualized measure of quality of life (QOL) called the Patient Generated Index (PGI). The domains identified with the PGI were then classified and grouped together using the World Health Organization's International Classification of Functioning, Disability and Health (ICF), and mapped onto the HUI2, HUI3, EQ-5D and SF-6D.

RESULTS

A total of 185 persons with MS were interviewed on the PGI. The sample was relatively young (mean age 43) and predominantly female. Both men and women had mild disability with a median Expanded Disability Status Scale (EDSS) score of 2. The top 10 domains that patients identified to be the most affected by their MS were, work (62%), fatigue (48%), sports (39%), social life (28%), relationships (23%), walking/mobility (22%), cognition (21%), balance (14%), housework (12%) and mood (11%). The SF-6D included the most number of domains (6 domains) important to people with MS, followed by the EQ-5D (4 domains) and the HUI2 (4 domains) and then the HUI3 (3 domains). The mean and standard deviation (SD) for the PGI, EQ-5D and the SF-6D were 0.50 (SD 0.25), 0.69 (0.18) and 0.69 (0.13), respectively. The magnitude of difference between the PGI and the generic utility measures was large and statistically significant.

CONCLUSION

Although the generic utility measures included certain items that were important to people with MS, there were several that were missing. An important consequence of this mismatch was that values of QOL derived from the PGI were importantly and significantly lower than those estimated using any of the generic utility measures. This could have a substantial impact in evaluating the effect of interventions for people with MS.

Use of senior center and the health-related quality of life in Korean older adults

Objective

The purpose of the present study was to examine the relationship between the use of senior center and health-related quality of life in Korean older adults.

Methods

A questionnaire survey was conducted to two types of older adults who lived in Busan, Korea: 154 older adults who used a senior center and 137 older adults who did not use a senior center. The Korean version of short-form 36-item health survey was administered to assess the health-related quality of life. Demographic variables were obtained from a questionnaire. These were gender, age, family status, marital status, education, monthly income, present illness, body mass index and physical activity.

Results

The 8-domain scales of physical function and role-physical were significantly higher in the users of the senior center compared with the non-users (F=4.87, p=0.027 and F=7.02, p=0.009, respectively). The 8-domain scales of vitality was also significantly higher in the users of the senior center compared with the non-users (F=7.48, p=0.007).

Conclusions

The present study showed that the users of the senior center have higher physical function, role-physical and vitality compared with the non-users. These findings suggest that although the results are unable to specify causal relationships using the senior center may lead to some improvement in health-related quality of life.

Utilities and disutilities for attributes of injectable treatments for type 2 diabetes

INTRODUCTION

Although cost-utility models are frequently used to estimate treatment outcomes for type 2 diabetes, utilities are not available for key attributes of injectable treatments. The purpose of this study was to identify the utility or disutility of three injection-related attributes (dose frequency, dose flexibility, injection site reaction) that may influence patient preference.

METHODS

Patients with type 2 diabetes in Scotland completed standard gamble (SG) interviews to assess the utility of hypothetical health states and their own current health state. The EQ-5D, PGWB, IWQOL-Lite, and QIDS were also administered. Construct validity and differences among health states were examined.

RESULTS

A total of 151 patients completed interviews. Of the three injection-related attributes, dose frequency was the only attribute with a statistically significant impact on utility (in a multiple regression model, p = 0.01). Weekly injections were associated with an average added utility of 0.023 in comparison to everyday injections. Flexible dosing and injection site reactions resulted in somewhat smaller utility shifts that were in the expected directions (+0.006 and -0.011, respectively). SG utility of current health (mean = 0.897) demonstrated construct validity through statistically significant correlations with patient-reported outcome measures.

DISCUSSION

The three injection attributes were associated with small utility shifts in the expected directions. Dose frequency appears to be the most important of the three attributes from the patients' perspective. The vignette-based SG approach was feasible and useful for assessing added utility or disutility of injection-related attributes associated with treatments for type 2 diabetes.

Cost-effectiveness of the Boston keratoprosthesis

PURPOSE

To conduct a cost-utility analysis and determine the cost-effectiveness of the Boston Keratoprosthesis (Boston Kpro).

DESIGN

Retrospective cohort study.

METHODS

setting: The Massachusetts Eye and Ear Infirmary corneal service. patients: Inclusion required a minimum 2-year follow-up. Patients with autoimmune diseases and chemical burns were excluded. Eighty-two patients were included with various indications for surgery. intervention: The keratoprosthesis is a collar button-shaped polymethylmethacrylate (PMMA) device consisting of 2 curved plates sandwiched around a corneal donor (allo)graft. The device is assembled intraoperatively and sutured to a patient's eye after removing the diseased cornea.

MAIN OUTCOME MEASURES

Average cost-effectiveness of the keratoprosthesis was determined by cost-utility analysis, using expected-value calculations and time-tradeoff utilities. The comparative effectiveness, or gain in quality-adjusted life years (QALYs), was also sought. Cost-effectiveness was compared to recently published data on penetrating keratoplasty (PK).

RESULTS

A total discounted incremental QALY gain for the Boston Kpro of 0.763 correlated with a conferred QALY gain of 20.3% for the average patient. The average cost-effectiveness of the keratoprosthesis was $16 140 per QALY.

CONCLUSIONS

Comparable to corneal transplantation, with a cost-effectiveness between $12 000 and $16 000 per QALY, the keratoprosthesis can be considered highly cost-effective.

Population-based utilities for upper extremity functions in the setting of tetraplegia

PURPOSE

People with tetraplegia face substantial physical and financial hardships. Although upper extremity reconstruction has been advocated for people with tetraplegia, these procedures are markedly underused in the United States. Population-based preference evaluation of upper extremity reconstruction is important to quantify the value of these reconstructive procedures. This study sought to establish the preferences for 3 health states: tetraplegia, tetraplegia with corrected pinch function, and tetraplegia with corrected elbow extension function.

METHODS

A computer-based, time trade-off survey was administered to a cohort of 81 able-bodied second-year medical students who served as a surrogate for the general public. This survey instrument has undergone pilot testing and has established face validity to evaluate the 3 health states of interest. Utilities were calculated based on an estimated 20 years of remaining life.

RESULTS

The mean utility for the tetraplegic health state was low. On average, respondents gave up 10.8 +/- 5.0 out of a hypothetical 20 years for perfect health, for a utility of tetraplegia equal to 0.46. For recovery of pinch function, respondents gave up an average of 6.5 +/- 4.3 years, with a corresponding health utility of 0.68. For recovery of elbow extension function, respondents gave up an average of 7.6 +/- 4.5 years, with a corresponding health utility of 0.74.

CONCLUSIONS

This study established the preferences for 2 upper extremity surgical interventions: tetraplegia with pinch and tetraplegia with elbow extension. The findings from this study place a high value on upper-limb reconstructive procedures with tetraplegia.

Using conjoint analysis to estimate healthy-year equivalents for acute conditions: an application to vasomotor symptoms

OBJECTIVE

Conventional standard gamble and time trade-off methods may be inappropriate for eliciting preferences for some health states because both require subjects to make trade-offs between a morbid health state and death. Thus, the objective of this study is to demonstrate the use of conjoint analysis to obtain time trade-off estimates of healthy-year equivalents (HYEs) for clinically relevant durations and severities of acute, self-limiting, or nonfatal conditions such as vasomotor symptoms.

METHODS

A self-administered, web-enabled, graded-pairs conjoint-analysis survey was developed to elicit women's preferences for reducing the frequency and severity of vasomotor symptoms (daytime hot flushes and night sweats). Observed trade-offs between symptom duration and symptom relief were used to calculate HYEs for different severities and durations of vasomotor symptoms.

RESULTS

A total of 523 women with a mean age of 52 years completed the survey. For these women, an improvement from severe to moderate vasomotor symptoms yields a gain of 4.44 HYEs, and an improvement from moderate to mild vasomotor symptoms over 1 year yields a gain of 4.62 HYEs over a period of 7 years. HYE gains for symptom relief are larger for younger women than for older women.

CONCLUSIONS

Conjoint analysis is a feasible method for estimating HYEs for acute, self-limiting, or nonfatal conditions. This approach may provide an alternative utility-elicitation method when conventional standard gamble and time trade-off methods are inappropriate to the decision context.

Health-related quality of life (HRQoL) domains most valued by urban IsiXhosa-speaking people

PURPOSE

The aim of the study was to investigate and identify aspects of health-related quality of life (HRQoL) that are most valued by IsiXhosa-speaking people resident in underresourced areas of Cape Town, South Africa.

METHODOLOGY

Fifty-seven domains of HRQoL were identified as important through group discussions with IsiXhosa-speaking people. Participants randomly selected from the community (n = 601) and from individuals seeking medical attention at a local clinic (n = 102) graded the domains on a visual analogue scale (VAS) ranging from 0 for "not at all important" to 10 for " very important". The domains were then mapped to the categories of the International Classification of Functioning, Disability and Health.

RESULTS

The domains regarded as being most important were Food availability [9.5, standard deviation (SD) = 1.52), Owning a brick house (9.4, SD = 1.57), Access to medical services (9.4, SD = 1.55) and Family safety (9.4, SD = 1.7). Having no bodily pain ranked 40th. Environmental Factors were valued significantly more than the other two categories, and those related to Body Functions were valued higher than domains in the category of Activity and Participation.

DISCUSSION AND CONCLUSION

Despite being asked specifically to answer the questions in relation to their health status, the participants apparently did not differentiate between general quality of life (QoL) and specific HRQoL. It appears that members of an underresourced community regard socioeconomic and service delivery aspects of their lives as integral to their perceived state of health. It may be that it is not possible to separate out factors relating to general QoL from those specifically related to HRQoL in an underresourced population, and such populations might not be suitable for inclusion in certain clinical trials where an improvement in HRQoL is the required outcome. Alternatively, if an HRQoL instrument is to be used to monitor the impact of medical interventions, the inclusion of Environmental Factors should be considered.

Health-related quality of life (HRQoL) domains most valued by urban isiXhosa-speaking people

PURPOSE

The aim of the study was to investigate and identify aspects of health-related quality of life (HRQoL) that are most valued by isiXhosa-speaking people resident in under-resourced areas of Cape Town.

METHODOLOGY

Fifty-seven domains of HRQoL were identified as important through group discussions with isiXhosa-speaking people. Participants randomly selected from the community (n = 601) and from individuals seeking medical attention at a local clinic (n = 102) graded the domains on a visual analogue scale (VAS) ranging from 0 as "not at all important" to 10 as " very important". The domains were then mapped to the categories of the International Classification of Functioning, Disability, and Health.

RESULTS

The domains regarded as being most important were food availability (9.5, SD = 1.52), owning a brick house (9.4, SD = 1.57), access to medical services (9.4, SD = 1.55), and family safety (9.4, SD = 1.7). Having no bodily pain was ranked 40th. Environmental factors were valued significantly more than the other two categories and those related to body functions were valued more highly than domains in the category of activity/participation.

DISCUSSION AND CONCLUSION

Despite being asked specifically to answer the questions in relation to their health status, the participants apparently did not differentiate between general quality of life (QoL) and specific HRQoL. It appears that members of an under-resourced community regard socioeconomic and service delivery aspects of their lives as integral to their perceived state of health. It may be that it is not possible to separate factors relating to general quality of life from those specifically related to HRQoL in an under-resourced population and such populations might not be suitable for inclusion in certain clinical trials where improvement in HRQoL is the required outcome. Alternatively, if a HRQoL instrument is to be used to monitor the impact of medical intervention, the inclusion of environmental factors should be considered.

Global Cost-effectiveness of Cataract Surgery

OBJECTIVE

To determine the cost-effectiveness of cataract surgery worldwide and to compare it with the cost-effectiveness of comparable medical interventions.

DESIGN

Meta-analysis.

PARTICIPANTS

Approximately 12,000 eyes in the studies selected.

METHODS

Articles were identified by searching the literature using the phrase cataract surgery, in combination with the terms cost, cost-effectiveness, and cost-utility. Terms used for the comparable medical interventions search included epileptic surgery, hip arthroplasty, knee arthroplasty, carpal tunnel surgery, and defibrillator implantation. The search was restricted to the years 1995 through 2006. Cataract surgery costs were converted to 2004 United States dollars (US$). Cost-utility was calculated using: (1) costs discounted at 3% for 12 years with a discounted quality-adjusted life years (QALY) gain of 1.25 years, and (2) costs discounted at 3% for 5 years with a discounted QALY gain of 0.143 years. The Cataract Surgery Affordability Index (CSAI) for each country was calculated by dividing the cost of cataract surgery by the gross national income per capita for the year 2004.

MAIN OUTCOME MEASURES

Cost-utility in 2004 US$/QALY and affordability of cataract surgery relative to the United States.

RESULTS

Cost-utility values for cataract surgery (first eye) varied from $245 to $22,000/QALY in Western countries and from $9 to $1600 in developing countries. In developed countries, the cost-effectiveness of cataract surgery estimated by Choosing Interventions That Are Cost Effective ranged from, in international dollars (I$), I$730 to I$2400/disability-adjusted life years (DALY) averted, and I$90 to I$370/DALY averted in developing countries. The CSAI varied from 17% to 189% in developed countries and 29% to 133% in developing countries compared with the United States. The cost-utility of other comparable medical interventions was: epileptic surgery, $4000 to $20,000/QALY; hip arthroplasty, $2300 to $4800/QALY; knee arthroplasty, $6500 to $12,700/QALY; carpal tunnel surgery, $140 to $280/QALY; and defibrillator implantation, $700 to $23,000/QALY.

CONCLUSIONS

The cost-utility of cataract surgery varies substantially, depending how the benefit is assessed and on the duration of the assumed benefit. Cataract surgery is comparable in terms of cost-effectiveness to hip arthroplasty, is generally more cost-effective than either knee arthroplasty or defibrillator implantation, and is cost-effective when considered in absolute terms. The operation is considerably cheaper in Europe and Canada compared with the United States and is affordable in many developing countries, particularly India.

Obese versus non-obese patients with type 2 diabetes: patient-reported outcomes and utility of weight change

INTRODUCTION

This study (1) used patient-reported outcome measures to assess and compare the health status of type 2 diabetes patients with and without obesity and (2) assessed the value of weight change among obese and non-obese subgroups, using standard gamble (SG) utility methodology.

METHODS

Among a sample with type 2 diabetes in the United Kingdom, individuals with obesity (BMI > or = 30 kg/m2) were identified and compared to non-obese patients. Patients completed the EQ-5D, Psychological General Well-Being Index, Appraisal of Diabetes Symptoms, and Diabetes Symptom Checklist-Revised (DSC-R). SG interviews assessed the utility of the 'basic' type 2 diabetes health state anchored to respondents' body weight, as well as health states with altered weight.

RESULTS

A total of 129 patients (74 obese; 55 non-obese) completed interviews (mean age 55.9 years; 64.3% male). Obese patients reported lower health status (EQ-5D VAS; between-group difference: p < 0.001) and greater symptom impact (several DSC-R scales, p < 0.05). Utilities of the basic health state were 0.86 (obese) and 0.91 (non-obese; p = 0.02). Hypothetical health states with higher weight received lower utilities, whereas reduced weight was associated with increased utility. There was a between-group difference in the disutility associated with 5% higher weight (obese 0.068; non-obese 0.051; p = 0.03).

DISCUSSION

Compared with non-obese patients, the obese group reported lower health status and greater symptom impact. SG interviews found an inverse relationship between weight and utility. Furthermore, obese patients with type 2 diabetes may value weight change differently than non-obese patients. Study limitations include the sample size and the use of a patient sample, rather than a sample selected from the general population. Overall, the results demonstrate that utilities can differ by patient subgroups, even among patients with the same diagnosis.

Utilities and disutilities for type 2 diabetes treatment-related attributes

INTRODUCTION

Although cost-utility analyses are frequently used to estimate treatment outcomes for type 2 diabetes, utilities are not available for key medication-related attributes. The purpose of this study was to identify the utility or disutility of diabetes medication-related attributes (weight change, gastrointestinal side effects, fear of hypoglycemia) that may influence patient preference.

METHODS

Patients with type 2 diabetes in Scotland and England completed standard gamble (SG) interviews to assess utility of hypothetical health states and their own current health state. The EQ-5D, PGWB, and Appraisal of Diabetes Symptoms were administered. Construct validity and differences among health states were examined with correlations, t-tests, and ANOVAs.

RESULTS

A total of 129 patients (51 Scotland; 78 England) completed interviews. Mean utility of diabetes without complications was 0.89. Greater body weight was associated with disutility, and lower body weight with added utility (e.g., 3% higher = -0.04; 3% lower = +0.02). Gastrointestinal side effects and fear of hypoglycemia were associated with significant disutility (p < 0.001). SG utility of current health (mean = 0.87) demonstrated construct validity through correlations with patient-reported outcome measures (r = 0.08-0.31).

DISCUSSION

The vignette-based approach was feasible and useful for assessing added utility or disutility of medication-related attributes.

Patient preference quality of life measures in dermatology

Patient quality of life (QOL) is an important aspect of health care. It is crucial that we continue to develop instruments to assist in detecting burden of disease, interpreting outcomes of clinical trials, determining cost effectiveness of therapies, and guiding clinical decision making. The measurement of patient preferences, specifically utilities and contingent valuation, for health states provides data that can assist in the aforementioned endeavors. Patient preferences have been measured in many areas of medicine. However, it is relatively new to the field of dermatology. The present authors provide an overview of the basic concepts of patient preference measures and how they compare to the widely used health status instruments. Various techniques that have been used to elicit patient preferences are discussed, including standard gamble, time trade-off, willingness-to-pay, rating scales, health utilities index, and EuroQol (EQ-5D). In addition, the present authors review the current literature reporting utilities relevant to dermatology.

The determinants of health-related quality of life in urban and rural isi-Xhosa-speaking people with disabilities

This study aimed to establish the determinants of health-related quality of life in a rural and an urban sample of Xhosa-speaking people with disability. The sample was a convenience sample and was identified through a 'snowballing' process initiated by enumerators who were all members of Disabled People South Africa. The Xhosa version of the EQ-5D was utilized and the visual analogue scale which ranges from 0 (worst imaginable health state) to 100 (best imaginable health state) was used as the dependent measure. The sample consisted of 244 rural and 61 urban respondents, demonstrating a preponderance of physical disabilities. The urban sample reported more problems in each of the descriptor domains. The visual analogue scale score showed a bimodal distribution. The results of the multiple regression analysis indicated that the presence of pain detracted most from health-related quality of life (-20%), followed by anxiety and depression (-10%), and difficulty with performance of usual activities (-10%). Rural participants, with the same impairment level, reported 8% poorer health-related quality of life. The mean visual analogue scale scores were low (in the 60s), and would indicate that the majority of people living with disability do not necessarily adapt to their functional limitations and continue to experience diminished health-related quality of life. The bimodal distribution, however, did indicate that some respondents enjoyed good health-related quality of life. There is a need to manage symptoms, particularly pain and depression, as these have a severe negative impact on health-related quality of life. The rural setting seemed to contribute to a worse perceived health-related quality of life. This effect needs to be factored in when evaluating programmes.

Can differences in breast cancer utilities explain disparities in breast cancer care?

BACKGROUND

Black, older, and less affluent women are less likely to receive adjuvant breast cancer therapy than their counterparts. Whereas preference contributes to disparities in other health care scenarios, it is unclear if preference explains differential rates of breast cancer care.

OBJECTIVE

To ascertain utilities from women of diverse backgrounds for the different stages of, and treatments for, breast cancer and to determine whether a treatment decision modeled from utilities is associated with socio-demographic characteristics.

PARTICIPANTS

A stratified sample (by age and race) of 156 English-speaking women over 25 years old not currently undergoing breast cancer treatment.

DESIGN AND MEASUREMENTS

We assessed utilities using standard gamble for 5 breast cancer stages, and time-tradeoff for 3 therapeutic modalities. We incorporated each subject's utilities into a Markov model to determine whether her quality-adjusted life expectancy would be maximized with chemotherapy for a hypothetical, current diagnosis of stage II breast cancer. We used logistic regression to determine whether socio-demographic variables were associated with this optimal strategy.

RESULTS

Median utilities for the 8 health states were: stage I disease, 0.91 (interquartile range 0.50 to 1.00); stage II, 0.75 (0.26 to 0.99); stage III, 0.51 (0.25 to 0.94); stage IV (estrogen receptor positive), 0.36 (0 to 0.75); stage IV (estrogen receptor negative), 0.40 (0 to 0.79); chemotherapy 0.50 (0 to 0.92); hormonal therapy 0.58 (0 to 1); and radiation therapy 0.83 (0.10 to 1). Utilities for early stage disease and treatment modalities, but not metastatic disease, varied with socio-demographic characteristics. One hundred and twenty-two of 156 subjects had utilities that maximized quality-adjusted life expectancy given stage II breast cancer with chemotherapy. Age over 50, black race, and low household income were associated with at least 5-fold lower odds of maximizing quality-adjusted life expectancy with chemotherapy, whereas women who were married or had a significant other were 4-fold more likely to maximize quality-adjusted life expectancy with chemotherapy.

CONCLUSIONS

Differences in utility for breast cancer health states may partially explain the lower rate of adjuvant therapy for black, older, and less affluent women. Further work must clarify whether these differences result from health preference alone or reflect women's perceptions of sources of disparity, such as access to care, poor communication with providers, limitations in health knowledge or in obtaining social and workplace support during therapy.

Assessing responsiveness of generic and specific health related quality of life measures in heart failure

Background

Responsiveness, or sensitivity to clinical change, is an important consideration in selection of a health-related quality of life (HRQL) measure for trials or clinical applications. Many approaches can be used to assess responsiveness, which may affect the interpretation of study results. We compared the relative responsiveness of generic and heart failure specific HRQL instruments, as measured both by common psychometric indices and by external clinical criteria.

Methods

We analyzed data collected at baseline and 6-weeks in 298 subjects with heart failure on the following HRQL measures: EQ-5D (US, UK, and VAS Scoring), Kansas City Cardiomyopathy Questionnaire (KCCQ) (Clinical and Overall Summary Score), and RAND12 (Physical and Mental Component Summaries). Three external indicators of clinical change were used to classify subjects as improved, deteriorated, or unchanged: 6-minute walk test, New York Heart Association (NYHA) class, and physician global rating of change. Four responsiveness statistics (T-test, effect size, Guyatt's responsiveness statistic, and standardized response mean) were used to evaluate the responsiveness of the select measures. The median rank of each HRQL measure across responsiveness indices and clinical criteria was then determined.

Results

Average age of subjects was 60 years, 75 percent were male, and had moderate to severe heart failure symptoms. Overall, the KCCQ Summary Scores had the highest relative ranking, irrespective of the responsiveness index or external criterion used. Importantly, we observed that the relative ranking of responsiveness of the generic measures (i.e. EQ-5D, RAND12) was influenced by both the responsive indices and external criterion used.

Conclusion

The disease specific KCCQ was the most responsive HRQL measure assessing change over a 6-week period, although generic measures provide information for which the KCCQ is not suitable. The responsiveness of generic HRQL measures may be affected by the index used, as well as the external criterion to classify patients who have clinically change or remained stable.

Do visual analogue scale (VAS) derived standard gamble (SG) utilities agree with Health Utilities Index utilities? A comparison of patient and community preferences for health status in rheumatoid arthritis patients

Background

Assessment of Health Related Quality of Life (HRQL) has become increasingly important and various direct and indirect methods and instruments have been devised to measure it. In direct methods such as Visual Analog Scale (VAS) and Standard Gamble (SG), respondent both assesses and values health states therefore the final score reflects patient's preferences. In indirect methods such as multi-attribute health status classification systems, the patient provides the assessment of a health state and then a multi-attribute utility function is used for evaluation of the health state. Because these functions have been estimated using valuations of general population, the final score reflects community's preferences. The objective of this study is to assess the agreement between community preferences derived from the Health Utilities Index Mark 2 (HUI2) and Mark 3 (HUI3) systems, and patient preferences.

Methods

Visual analog scale (VAS) and HUI scores were obtained from a sample of 320 rheumatoid arthritis patients. VAS scores were adjusted for end-aversion bias and transformed to standard gamble (SG) utility scores using 8 different power conversion formulas reported in other studies. Individual level agreement between SG utilities and HUI2 and HUI3 utilities was assessed using the intraclass correlation coefficient (ICC). Group level agreement was assessed by comparing group means using the paired t-test.

Results

After examining all 8 different SG estimates, the ICC (95% confidence interval) between SG and HUI2 utilities ranged from 0.45 (0.36 to 0.54) to 0.55 (0.47 to 0.62). The ICC between SG and HUI3 utilities ranged from 0.45 (0.35 to 0.53) to 0.57 (0.49 to 0.64). The mean differences between SG and HUI2 utilities ranged from 0.10 (0.08 to 0.12) to 0.22 (0.20 to 0.24). The mean differences between SG and HUI3 utilities ranged from 0.18 (0.16 to 0.2) to 0.28 (0.26 to 0.3).

Conclusion

At the individual level, patient and community preferences show moderate to strong agreement, but at the group level they have clinically important and statistically significant differences. Using different sources of preference might alter clinical and policy decisions that are based on methods that incorporate HRQL assessment. VAS-derived utility scores are not good substitutes for HUI scores.

Do clinical marker states improve responsiveness and construct validity of the standard gamble and feeling thermometer: a randomized multi-center trial in patients with chronic respiratory disease

BACKGROUND

Optimizing the validity and responsiveness of utility measures will enhance their usefulness in randomized trials. We evaluated the impact of clinical marker state (CMS) rating prior to patients' rating their own health on two utility instruments (feeling thermometer (FT) and standard gamble (SG)) in patients with chronic respiratory disease (CRD).

METHODS

We randomized 182 patients with CRD to complete the FT (self-administered) and SG with CMS (FT+/SG+, n=91) or without marker states (FT-/SG-, n=91) before and after undergoing respiratory rehabilitation in a multi-center trial.

RESULTS

Use of CMS did not influence baseline utility scores. Improvement after therapy on the scale from 0 (dead) to 1.0 (full health) was 0.04 both in FT+ (p=0.03) and FT- (p=0.02; the difference between FT+ and FT- was 0.00, p=0.83). Improvement on the SG was 0.05 in both SG+ (p=0.08) and SG- (p=0.04; difference between SG+ and SG- 0.00, p=0.95). Correlations with other health related quality of life scores were highest for FT+.

CONCLUSION

Administration of CMS did not improve responsiveness of the FT but may have improved construct validity. The SG showed limited construct validity and responsiveness that was not influenced by CMS use.

Assessment of health state utilities for attention-deficit/hyperactivity disorder in children using parent proxy report

This study used standard gamble (SG) utility interviews to assess parent preferences for health states of childhood attention-deficit/hyperactivity disorder (ADHD). Health state utilities are needed to calculate quality-adjusted life years (QALYs), a critical outcome measure in cost-effectiveness studies of new treatments. Parents (n = 43) of children diagnosed with ADHD completed SG utility interviews, rating their child's current health and 11 hypothetical health states describing untreated ADHD and ADHD treated with a stimulant or non-stimulant. Parents completed questionnaires on their children's symptoms and health-related quality of life (HRQL). Parents' SG rating of their child's current health state (mean of 0.74 on a utility scale ranging from 0 to 1) was significantly correlated with inattentive, hyperactive, and overall ADHD symptoms (r = 0.37, 0.36, and 0.40 respectively; p < 0.05) and psychosocial HRQL domains. Hypothetical health state utilities ranged from 0.48 (severe untreated ADHD) to 0.88 (effective and tolerable non-stimulant treatment). Comparisons between health states found expected differences between untreated mild, moderate, and severe ADHD health states. When both treatments were effective and tolerable, parents preferred the non-stimulant health state over the stimulant health state (p < 0.03). Results suggest that parent SG interviews are a feasible and useful method for obtaining utility scores that can be used in cost-effectiveness models of ADHD treatment.

The impact of illness in patients with moderate to severe gastro-esophageal reflux disease

Background

Gastro-esophageal reflux disease (GERD) is a common disease. It impairs health related quality of life (HRQL). However, the impact on utility scores and work productivity in patients with moderate to severe GERD is not well known.

Methods

We analyzed data from 217 patients with moderate to severe GERD (mean age 50, SD 13.7) across 17 Canadian centers. Patients completed three utility instruments – the standard gamble (SG), the feeling thermometer (FT), and the Health Utilities Index 3 (HUI 3) – and several HRQL instruments, including Quality of Life in Reflux and Dyspepsia (QOLRAD) and the Medical Outcomes Short Form-36 (SF-36). All patients received a proton pump inhibitor, esomeprazole 40 mg daily, for four to six weeks.

Results

The mean scores on a scale from 0 (dead) to 1 (full health) obtained for the FT, SG, and HUI 3 were 0.67 (95% CI, 0.64 to 0.70), 0.76 (95% CI, 0.75 to 0.80), and 0.80 (95% CI, 0.77 to 0.82) respectively. The mean scores on the SF-36 were lower than the previously reported Canadian and US general population mean scores and work productivity was impaired.

Conclusion

GERD has significant impact on utility scores, HRQL, and work productivity in patients with moderate to severe disease. Furthermore, the FT and HUI 3 provide more valid measurements of HRQL in GERD than the SG. After treatment with esomeprazole, patients showed improved HRQL.

Development, reliability and validity of a new measure of overall health for pre-school children

BACKGROUND

Few comprehensive systems are available for assessing and reporting the overall health of preschool children.

OBJECTIVES

(i) To develop a multi-dimension health status classification system (HSCS) to describe pre-school (PS) children 2.5-5 years of age; (ii) to report reliability and validity of the newly developed measure.

DESIGN

Existing systems (Health Utilities Index, Mark 2 and 3) were adapted for application to a pre-school population. The new system was tested for acceptability, validity and reliability.

PARTICIPANTS

Three cohorts of children and their parents from Canada and Australia were utilized: Cohort 1 (MAC)-101 3-years old very low birthweight (VLBW, <1500 g) and 50 same age term children from Canada; Cohort 2 (AUS)-150 VLBW 3-years old from Australia; Cohort 3 (OMG)-222 3-years old with cerebral palsy (CP) from Ontario.

METHODS

Parental intra-rater reliability was evaluated by completion of the HSCS-PS Parent questionnaire (MAC) at the clinic visit and again 14 days later. Health professionals (MAC) completed the HSCS-PS Clinician questionnaire. Percent agreement and Kappa values were used to assess parent-clinician agreement. Concurrent validity was tested in two populations of VLBW children (MAC and AUS) and a reference group of term children (MAC) by exploring the relationships between dimensions of the HSCS-PS and well-recognized norm-referenced measures: the Bayley Scales of Infant Development (BSID-II), the Vineland Adaptive Behavior Scales (VABS) and the Stanford-Binet (SB). Construct validity was tested by comparing ratings on both the HSCS-PS and the Gross Motor Function classification system (GMFCS) using a population of pre-school children with CP. Analyses were done using chi2, ANOVA and correlations with tau-b statistic.

RESULTS

The HSCS-PS has 12 dimensions and 3-5 levels per dimension. Response rate for parental intra-rater reliability was 95%, with percent agreement ranging between 86 and 100%. Kappa values for various dimensions ranged from 0.38 to 1.00. Inter-rater reliability between parents and clinicians showed agreement ranging from 72 to 100%. Kappa values ranged from 0.30 to 1.00. CONCURRENT VALIDITY: There was a statistically significant gradient between HSCS-PS Mobility levels and motor scale scores of the BSID-II and VABS. A significant gradient also occurred when comparing HSCS-PS cognition levels to psychometric scores on the BSID-II and SB, as well as HSCS-PS self-care levels compared to VABS Daily Living scores. DISCRIMINATIVE AND CONSTRUCT VALIDITY: Birthweight category was shown to be a significant determinant of proportion of children with multiple HSCS-PS dimensions affected. In addition, HSCS-PS dimension levels were congruent with GMFCS levels where expected: mobility had excellent correlation; self-care, dexterity, speech and cognitive dimensions had moderate correlations.

CONCLUSIONS

The HSCS-PS is readily accepted, quick to complete, widely applicable and provides a multi-dimensional description of health status. Preliminary assessments of reliability and validity are promising. The HSCS-PS can discriminate across populations by birthweight and shows strong relationships with standardized psychometric measures in comparable domains. It can pro- vide a summary profile of functional limitations in various populations of pre-school children in a consistent manner across programs and in different settings.

Measurement of agreement on health-related quality of life changes in response to respiratory rehabilitation by patients and physicians--a prospective study

INTRODUCTION

To provide optimal care for patients with chronic obstructive pulmonary disease physicians need to understand if their patients benefit from an intervention. The objective of this study was to assess agreement between patients and physicians on health-related quality of life (HRQL) changes in response to respiratory rehabilitation and to explore sources for disagreement.

METHODS

Sixty-one patients rated their health states on a validated preference-based instrument, the feeling thermometer (FT). In an analogous manner, the eight treating physicians rated the patients' health states on the FT. Patients and physicians were blinded to each other's ratings. We calculated intraclass correlation coefficients (ICC) to assess agreement between patients and physicians and used HRQL instruments and the 6-min walking test to assess the evaluative properties of the FT.

RESULTS

We found moderate agreement at baseline (ICC 0.40, P = 0.018) and follow-up (ICC 0.49, P = 0.008) but large disagreement about change scores (ICC 0.02, P = 0.46). Patients' FTchange scores correlated well with change scores of the Chronic Respiratory Questionnaire, SF-36 and the Borg scale for dyspnoea whereas physicians' FT change scores correlated significantly with the change score of the 6- min walking test (r = 0.33). Physicians' ratings showed an inconsistent pattern for correlations with HRQL measures.

CONCLUSIONS

There is large disagreement between patients and physicians on HRQL changes in response to respiratory rehabilitation. Investigators should assess whether the introduction of HRQL instruments into clinical practice raises the awareness of physicians towards HRQL and improves agreement with their patients.

A Randomized Multicenter Trial to Evaluate Simple Utility Elicitation Techniques in Patients With Gastroesophageal Reflux Disease

BACKGROUND

Despite recommendations that patients rating their own health using utility and preference measures such as the feeling thermometer (FT) and standard gamble (SG) should also rate hypothetical marker states, little evidence supports marker state use. We evaluated whether the administration of marker states improves measurement properties of the FT and SG.

METHODS

We randomized 217 patients with gastroesophageal reflux disease to complete the FT (self-administered) and SG with marker states (FT+ / SG+, n = 112) or without marker states (FT- / SG-, n = 105) before and after 4 weeks of treatment with a proton pump inhibitor, esomeprazole. Patients also completed other health-related quality of life instruments.

RESULTS

The use of marker states did not influence baseline utility scores (FT+ 0.66, FT- 0.68; SG+ 0.77, SG- 0.78, on a scale from 0 [dead] to 1.0 [full health]). Improvement after therapy was 0.21 in FT+ and 0.15 in FT- (both P < 0.001; difference between FT+ and FT- = 0.06, P = 0.02). Improvement in SG+ was 0.07 (P < 0.001) and 0.06 in SG- (P = 0.003) (difference between SG+ and SG- = 0.01, P = 0.63). Correlations with other health-related quality of life scores were generally stronger, with some statistically significant differences in correlations, for FT+ compared with FT-, but tended to be weaker for SG+ compared with SG-.

CONCLUSION

The administration of marker states improved the responsiveness and validity of the FT but not of the SG. Decisions about administering marker states should depend on whether the FT and SG is of primary interest and the importance of optimal validity and responsiveness relative to competing objectives such as efficiency.

A catalog of dermatology utilities: a measure of the burden of skin diseases

Utilities are measures of quality of life that reflect the strength of individuals' preferences or values for a particular health outcome. As such, utilities represent a measure of disease burden. The aim of this article is to introduce the concept of utilities to the dermatology community and to present a catalog of dermatology utilities obtained from direct patient interviews. Our data are based on 236 total subjects from Grady Hospital (Atlanta, GA), Stanford Medical Center (Palo Alto, CA), and Parkland Hospital (Dallas, TX). The mean time trade-off utilities ranged from 0.640 for blistering disorders to 1.000 for alopecia, cosmetic, and urticaria. The mean utility across all diagnoses was 0.943. We present utilities for 17 diagnostic categories and discuss the underlying reasons for the significant disease burden that these utilities represent. We also present these dermatology categories relative to noncutaneous diseases to place the cutaneous utilities in perspective and to compare the burden of disease. We have demonstrated that skin diseases have considerable burden of disease and provided a preliminary repository of utility data for future researchers and policy makers.

Estimation and comparison of derived preference scores from the SF-36 in lung transplant patients

The purpose of this study was to estimate and compare preference scores derived from MOS Short Form-36 (SF-36) data for a sample of lung transplant patients using three methodologies: Fryback et al. (Med Decis Making 1997; 17: 1-9), Nichol et al. (Med Decis Making 2001; 21: 105-112) and Brazier et al. (J Health Econ 2002: 21: 271-292). Data were gathered from 99 lung transplant recipients using a mail survey, which included the SF-36 and other health-related quality of life (HRQL) measures. The mean preference score for the sample was 0.643 (range 0.43-0.83), 0.765 (range 0.36-1.0), and 0.697 (range 0.33-1.00) for Fryback, Nichol and Brazier methods, respectively. Correlations between the derived scores and visual analogue ratings of health (0.58-0.68) and pulmonary symptoms (-0.59 to -0.62) were moderate to good and in the expected directions. The mean preferences of patients grouped by levels of dyspnea, depression symptoms, illness burden, and self-rated general health differed significantly with all methods and supported the construct validity of the derived scores as measures of preference. The Nichol and Brazier scores, both derived with standard gamble utilities, were generally higher than Fryback scores, which are not utility-based. Given the popularity of the SF-36, these three methods could be useful where direct elicitation of preferences is not feasible. Researchers must be cognizant of the derivation method used, as absolute preference levels, hence quality adjusted life years (QALYs), will differ by method.

Economic evaluation of treatments for cancer in childhood

Treatment of cancer in childhood is an expensive undertaking for the health-care system and for the affected families. As there is a substantial burden of treatment-related morbidity, it is important to determine whether the effects of treatment are worth these monetary costs, especially from a societal perspective. Economic evaluation affords a comparison of the costs and consequences (effects) of relevant therapeutic alternatives. Preference-based measures of health-related quality of life are particularly useful for assessing the effects of treatment, for these tools integrate mortality and morbidity. These measures provide utility scores that can be used as weights on survival data to compute quality-adjusted life years (QALYs). Costs are incurred both within and outside of the health-care system. The former should include those in front-line patient care departments (e.g. nursing); the pro-rated share of the expenses of service departments (e.g. materials management) to those in the front line; and the fully allocated costs for capital invested in lands, building and equipment. The latter are costs borne by families that are both out-of-pocket (e.g. for over-the-counter drugs) as well as related to time spent in providing care, which may involve foregone income. Costs and consequences should be subject to discounting; a process for converting those items incurred in the future into contemporary equivalents. Economic evaluation provides estimates of incremental discounted costs per discounted QALY gained. By almost any interpretative standard this appears attractive with respect to cancer in childhood. Examples are provided with the encouragement that economic evaluation be undertaken in more clinical trials in paediatric oncology.

The stability of utility scores: test-retest reliability and the interpretation of utility scores in elective total hip arthroplasty

PURPOSES

Are utility scores for hypothetical health states stable over time even when the health of the patient changes dramatically? Can investigators who use scores for hypothetical states be confident about the stability of those scores? The first purpose is to assess the stability of standard gamble utility scores for three hypothetical health states describing mild, moderate, and severe osteoarthritis (OA) (test-retest reliability). How should investigators interpret utility scores? The second purpose is to provide evidence on the marker-state approach to assist in interpreting utility scores.

BACKGROUND

SG scores for three hypothetical marker states and the patient's current state were obtained at multiple times in a longitudinal study of elective total hip arthroplasty (THA). SG scores for current health increased from a mean of 0.59 pre-surgery to 0.76 post-surgery.

METHODS

Test-retest reliability was assessed using the intra-class correlation coefficient (ICC). The effects of time on scores were analysed using an analysis of covariance.

RESULTS

At the group level the marker-state scores were stable. Mean scores for mild, moderate, and severe OA were 0.69, 0.61, and 0.41. With respect to test-retest reliability, ICCs varied from 0.49 to 0.62. In general, time did not affect the scores for the three marker states.

CONCLUSIONS

Group-level standard gamble scores are stable. At the individual level scores for hypothetical health states are somewhat stable over time. The marker states assist in interpretation indicating that, on average, THA converted moderate OA to better than mild.

Comparing directly measured standard gamble scores to HUI2 and HUI3 utility scores: group- and individual-level comparisons

Directly measured standard gamble (SG) utility scores reflect the respondent's assessment and valuation of their own health status. Scores from the health utilities index (HUI) are based on self-assessed health status but valued using community preferences obtained using the SG. Our objectives were to find if mean directly measured utility scores agree with mean HUI mark 2 (HUI2) and mean HUI mark 3 (HUI3) scores. Also, if individual directly measured utility scores agree with HUI2 and HUI3 scores, and whether HUI2 and HUI3 scores agree. Questionnaires based on the HUI2 and HUI3 health-status classification systems were administered by interviewers to 140 teenage survivors of extremely low birthweight (ELBW) and 124 control group teens. Respondents were asked to think about their own usual health states using six dimensions from HUI2 and value that state using the SG. Mean SG scores are compared with mean HUI2 and mean HUI3 scores using paired sample t-tests. Mean HUI2 scores are compared with mean HUI3 scores. Agreement among scores is assessed using intra-class correlation coefficient (ICC). The effect of severity of health-state morbidity on agreement was assessed using three approaches. ELBW cohort mean (standard deviation) SG, HUI2, and HUI3 scores were 0.90 (0.20), 0.89 (0.14), and 0.80 (0.22). Results for controls were 0.93 (0.11), 0.95 (0.09), and 0.89 (0.13). Mean SG and HUI2 scores did not differ; mean SG and HUI3 did differ; mean HUI2 and HUI3 also differed. At the individual level for ELBW, the ICCs between SG and HUI2, SG and HUI3, and HUI2 and HUI3 scores were 0.13, 0.28, and 0.64. For controls the ICCs were 0.14, 0.24, and 0.56. HUI2 scores appear to match directly measured utility scores reasonably well at the group level. HUI2 and HUI3 scores differ systematically. At the individual level, however, HUI2 and HUI3 scores are poor substitutes for directly measured scores.

Are health states 'timeless'? A case study of an acute condition: post-chemotherapy nausea and vomiting

RATIONALE, AIMS AND OBJECTIVES

The objective was to test whether individuals' responses to standard gamble (SG) and visual analogue scale (VAS) questions do not depend on the time horizon of the health scenario presented.

METHODS

Face-to-face interviews were conducted in a convenience sample of 18 women aged 22-50 years with no history of breast cancer or cancer requiring chemotherapy. Data were collected from March 2000 to June 2000 at a university in the Midwest of the United States of America. Preference weights were estimated using SG top-down titration method and VAS scaled from zero (death) to one (perfect health). Subjects were asked to rate their preferences if faced with two scenarios: post-chemotherapy nausea and vomiting (PCNV) occurring for 3 days (scenario 1), and PCNV lasting for the rest of their lives (scenario 2). Three PCNV health states of varying severity were tested: complete alleviation, partial alleviation, and no alleviation.

RESULTS

Paired-t-test analysis showed statistically significantly lower preference weights (P < 0.05) when the health state was for the rest of the respondent's life vs. 3 days. Mean SG weights for scenario 1 vs. scenario 2 were: 0.968 vs. 0.927 (complete alleviation), 0.942 vs. 0.810 (partial alleviation) and 0.866 vs. 0.644 (no alleviation). Mean VAS weights for scenario 1 vs. scenario 2 were: 0.741 vs. 0.676 (complete alleviation), 0.490 vs. 0.307 (partial alleviation) and 0.276 vs. 0.136 (no alleviation).

DISCUSSION AND CONCLUSIONS

For the majority of respondents the utility independence assumption for SG and VAS did not hold. Similar to Bala et al., the results of this study indicated that preference weights as measured by SG and VAS techniques were not 'timeless'. Regardless of the preference measure used, both SG and VAS yielded higher scores when PCNV lasted for a shorter period of time.

Health-related quality-of-life assessment of prenatal diagnosis: chorionic villi sampling and amniocentesis

This study assesses the health-related quality-of-life (HRQL) effects of chorionic villi sampling (CVS) and genetic amniocentesis (GA), including both process and outcomes of prenatal diagnosis. The HRQL of 126 women participating in a randomized controlled clinical trial of CVS versus GA in Toronto and Hamilton, Ontario, was assessed in four interviews at weeks 8, 13, 18, and 22 of pregnancy. Statistical analyses included analysis of variance, repeated measures analysis of covariance, chi-square, Fisher's exact test, Student's t-tests, and paired t-tests. Utility scores for patients undergoing CVS exceeded those for GA patients at week 18 (p = 0.04). Utility scores for hypothetical health states did not differ significantly by trial arm. CVS results in slightly improved HRQL during prenatal diagnosis. This advantage needs to be weighed against the high disutility patients attach to infrequent outcomes associated with pregnancy losses, equivocal diagnoses, and diagnostic inaccuracy.

Ethical issues in oncology biostatistics

A medical statistician's routine professional activities are likely to have important ethical consequences. This is due in part to the fact that good medical practice and scientifically valid medical research both require as precursors high quality statistical design and data analysis. In this paper I discuss various ethical issues that I have encountered while working as a biostatistician at M.D. Anderson Cancer Center. I describe particular experiences and the ethical issues involved. Topics include medical decision making, benefit-harm trade-offs, safety monitoring, adaptive randomization, informed consent, and publication bias.

Stability of time trade-off utilities for health states associated with the treatment of prostate cancer

BACKGROUND

Patients diagnosed with localized prostate cancer face several treatment options. Patient preferences for treatment side effects often dominate the decision making process. We proposed to learn more about the nature of patient preferences, or utilities, for these side effects.

METHODS

Two hundred and fifteen men were consecutively enrolled from three institutions for assessment after prostate needle biopsy. Baseline and 6 month follow-up assessments were done using the University of California, Los Angeles Prostate Cancer Index (UCLA PCI), and a laptop utility assessment application, U-Titer II. Patient utility was assessed for current pelvic functions as well as hypothetical pelvic dysfunctions. We calculated stability of utility scores and correlations between utility scores and UCLA PCI scores.

RESULTS

Utility scores for current pelvic functions exhibited a significant 'ceiling effect.' Utility scores for current pelvic functions and hypothetical impaired states were stable after 6 months in patients with negative biopsies. In patients who underwent treatment, utility for current sexual function decreased by 0.13 units (p < 0.00) and utility for current urinary function decreased by 0.09 units (p < 0.01). Utility for hypothetical stress urinary incontinence rose in men with a >25-point drop in UCLA PCI score.

CONCLUSION

Utilities for some 'current' pelvic functions decreased in tandem with UCLA PCI scores in men who experienced >25-point changes in these scores. Utilities for some 'hypothetical' pelvic dysfunctions rose as men began to actually experience functional changes in those areas.

Automated current health time-trade-off assessments in women's health

OBJECTIVE

To motivate the role for preference assessment in women's health and to report pilot data addressing the performance of automated time-trade-off (TTO) valuations of current health, which were developed to estimate quality-adjusted life years (QALYs) in the women's health setting.

METHODS

Values for current health relative to perfect health and death were assessed using an annual time trade-off (1-year horizon and sleep as the trading metaphor), a lifetime time trade-off, and a visual analog scale (VAS). All instruments were administered twice within a 12- to 14-day window among a convenience sample of 27 women.

RESULTS

Valuation of health was similar for both time trade-offs (mean of 0.95 for both), but was significantly lower for the VAS (mean of 0.84, Wilcoxon signed-rank p-value < 0.001). Reliability using the intraclass correlation coefficient was 0.67 +/- 0.09 and 0.75 +/- 0.07 for the annual and lifetime time trade-offs, respectively, and 0.89 +/- 0.03 for the VAS. Construct validity was supported by consistent trends in time-trade-off utilities across tertiles of the Short Form 36 (SF-36) general health subscale (trend test p-value < 0.001).

CONCLUSION

Automated time trade-offs for current health provide a promising approach for use in women's health studies where impact on QALYs must be measured. Natural areas of application include the economic evaluation of preventive interventions in postmenopausal women.

Multiattribute and single-attribute utility functions for the health utilities index mark 3 system

BACKGROUND

The Health Utilities Index Mark 3 (HUI3) is a generic multiattribute preference-based measure of health status and health-related quality of life that is widely used as an outcome measure in clinical studies, in population health surveys, in the estimation of quality-adjusted life years, and in economic evaluations. HUI3 consists of eight attributes (or dimensions) of health status: vision, hearing, speech, ambulation, dexterity, emotion, cognition, and pain with 5 or 6 levels per attribute, varying from highly impaired to normal.

OBJECTIVES

The objectives are to present a multiattribute utility function and eight single-attribute utility functions for the HUI3 system based on community preferences.

STUDY DESIGN

Two preference surveys were conducted. One, the modeling survey, collected preference scores for the estimation of the utility functions. The other, the direct survey, provided independent scores to assess the predictive validity of the utility functions.

MEASURES

Preference measures included value scores obtained on the Feeling Thermometer and standard gamble utility scores obtained using the Chance Board.

RESPONDENTS

A random sample of the general population (> or =16 years of age) in Hamilton, Ontario, Canada.

RESULTS

Estimates were obtained for eight single-attribute utility functions and an overall multiattribute utility function. The intraclass correlation coefficient between directly measured utility scores and scores generated by the multiattribute function for 73 health states was 0.88.

CONCLUSIONS

The HUI3 scoring function has strong theoretical and empirical foundations. It performs well in predicting directly measured scores. The HUI3 system provides a practical way to obtain utility scores based on community preferences.