Constructing health state preference values from descriptive quality of life outcomes: mission impossible?

Cost-effectiveness of a mindfulness-based mental health promotion program: economic evaluation of a nonrandomized controlled trial with propensity score matching

BACKGROUND

Mental health promotion programs have been shown to reduce the burden associated with mental distress and prevent the onset of mental disorders, but evidence of cost-effectiveness is scarce.

OBJECTIVE

To evaluate the cost-effectiveness of a mindfulness-based mental health prevention program provided by health coaches in a multi-site field setting in Germany.

METHODS

The single-study based economic evaluation was conducted as part of a nonrandomized controlled trial, comparing the effects of a group-based prevention program to usual care based on propensity score matching. Participants (N = 1166) were recruited via a large statutory health insurance fund. Health outcome was assessed with the Hospital Anxiety and Depression Scale (HADS). Cost outcomes were actually incurred costs compiled from the health insurance' records. Incremental cost-effectiveness ratios (ICER) were analyzed from a societal and a health care perspective for a 12-month time horizon with sampling uncertainty being handled using nonparametric bootstrapping. A cost-effectiveness acceptability curve was graphed to determine the probability of cost-effectiveness at different willingness-to-pay ceiling ratios.

RESULTS

From a societal perspective, prevention was cost-effective compared to usual-care by providing larger effects of 1.97 units on the HADS (95% CI [1.14, 2.81], p < 0.001) at lower mean incremental total costs of €-57 (95% CI [- 634, 480], p = 0.84), yielding an ICER of €-29 (savings) per unit improvement. From a health care perspective, the incremental health benefits were achieved at additional direct costs of €181 for prevention participants (95% CI [40, 318], p = 0.01) with an ICER of €91 per unit improvement on the HADS. Willingness-to-pay for the prevention program to achieve a 95% probability of being cost-effective compared to usual-care, was estimated at €225 per unit improvement on the HADS score from a societal, and €191 from a health care perspective respectively. Sensitivity analyses suggested differential cost-effect-ratios depending on the initial distress of participants.

LIMITATIONS

Due to the complexity of the field trial, it was not feasible to randomize participants and offer an active control condition. This limitation was met by applying a rigorous matching procedure.

CONCLUSIONS

Our results indicate that universal mental health promotion programs in community settings might be a cost-effective strategy to enhance well-being. Differences between the societal and health care perspective underline the call for joint funding in the dissemination of preventive services.

TRIAL REGISTRATION

German Clinical Trials Registration ID: DRKS00006216 (2014/06/11, retrospective registration).

Review of studies mapping from quality of life or clinical measures to EQ-5D: an online database

Systematic literature searches were conducted to identify studies that conducted statistical mapping to predict EQ-5D utilities or responses from any source instrument and reported the estimated algorithms in sufficient detail to allow other researchers to use them to predict EQ-5D in other studies. Ninety studies reporting 121 mapping algorithms met the inclusion criteria. The studies estimated EQ-5D utilities from 80 source instruments. All but two studies included direct utility mapping to predict EQ-5D utilities, while 20 studies (22%) conducted response mapping to predict responses to each EQ-5D domain. Seventy-two studies (80%) explored ordinary least squares regression and 16 (18%) used censored least absolute deviations (CLAD) models. The details of the studies identified are made available in an online database, which will be updated regularly to enable researchers to easily identify studies that can help them to estimate utilities for economic evaluation.

Korean guidelines for pharmacoeconomic evaluation (second and updated version) : consensus and compromise

The first version of the Korean guidelines for pharmacoeconomic evaluation was published by Health Insurance Review and Assessment Service (HIRA) in 2006. Since the introduction of the first version, domestic experience with the application of the recommendations has accumulated, and methodologies in certain areas have progressed considerably. Based on these experiences, HIRA initiated a guidelines revision project to address the need for revisions. The purpose of this study is to share the process used to complete these guideline revisions and to provide the contents of the revised guidelines. In developing the current revision, meetings with the advisory committee and working-level meetings with pharmaceutical companies were held several times to reach as much of a consensus as possible, and the results of a survey of pharmaceutical companies and decision makers regarding the existing guidelines were considered. The second version of the guidelines clarified the level of data requirement ('must', 'recommended', 'preferred') based on the data availability, the information needs of the decision makers and the strength of the evidence. The recommended perspective economic studies should take has been modified and additional guidance has been provided on QALY measurement. Manuals for systematic reviews and indirect comparisons have been published, and a standardized reporting format for expert opinions has been added. Sections on preferred methods for evaluations, sensitivity analysis, modelling and time horizon have been elucidated. The revised guidelines clarify the expression of the recommendations, making them more user-friendly, and provide more specific guidance to improve the quality and comparability across submissions.

Converting condition-specific measures into preference-based outcomes for use in economic evaluation

Quality-adjusted life-years (QALYs) play an important role in reimbursement decisions when one of the criteria is the cost-effectiveness of the health technology. While for many generic QALYs (e.g., based on the EQ-5D) are viewed as the gold standard, there has been a considerable increase in interest in using condition-specific data to generate QALYs. There are two main methods: mapping from the condition-specific data to a generic health-related quality of life measure; and direct valuation of condition-specific health states. Whether one believes condition-specific data are useful even if generic QALY data are available, or simply that condition-specific data are helpful in the absence of generic measures of health-related quality of life, it is timely to review recent research activity directed at making greater use of condition-specific data to inform assessments of cost-effectiveness.

Evaluation of content on EQ-5D as compared to disease-specific utility measures

PURPOSE

The goal of this study was to appraise the extent of unique content on disease-specific preference-based measures (DSPMs) when contrasted with the EQ-5D using published studies and to inform whether EQ-5D could be inadequate as a utility measure in its content coverage for a given disease-specific application.

METHODS

A structured search of published literature was performed using PubMed and EMBASE/Medline database from Jan 1, 1990 to Mar 31, 2011. Articles were eligible for inclusion if algorithms were developed to convert components from disease-specific measures into utility scores.

RESULTS

Of 1,029 articles identified, 50 studies satisfied the inclusion criteria. The most frequent conditions where DSPMs were developed included cancer (12 studies), coronary artery disease (4 studies), osteoarthritis, rheumatoid arthritis (3 studies of each), obesity, and stroke (2 studies of each). Most studies involved mapping items or scores from disease-specific non-preference-based measures onto a preference-based measure of health such as the EQ-5D. A substantial number of DSPMs appeared to include unique content not covered by EQ-5D dimensions.

CONCLUSIONS

Several conditions were identified as potential areas where the richness of the EQ-5D descriptive system could be enhanced. It is yet unclear whether added dimension(s) would contribute unique explained variance to a utility score. Given the resources required to rigorously develop a utility measure, the need for such measures should be carefully vetted.

The ability of cancer-specific and generic preference-based instruments to discriminate across clinical and self-reported measures of cancer severities

OBJECTIVE

To evaluate the validity of cancer-specific and generic preference-based instruments to discriminate across different measures of cancer severities.

METHODS

Patients with breast (n = 66), colorectal (n = 57), and lung (n = 61) cancer completed the EORTC QLQ-C30 and the FACT-G, as well as three generic instruments: the EQ-5D, the SF-6D, and the HUI2/3. Disease severity was quantified using cancer stage, Eastern Cooperative Oncology Group Performance Status (ECOG-PS) score, and self-reported health status. Comparative analyses confirmed the multi-dimensional conceptualization of the instruments in terms of construct and convergent validity.

RESULTS

In general, the instruments were able to discriminate across severity measures. The instruments demonstrated moderate to strong correlation with each other (r = 0.37-0.73). Not all of the measures could discriminate between different groups of disease severity: the EQ-5D and SF-6D were less discriminative than the HUI2/3 and the cancer-specific instruments.

CONCLUSION

The cancer-specific and generic preference-based instruments demonstrated to be valid in discriminating across levels of ECOG-PS scores and self-reported health states. However, the usefulness of the generic instruments may be limited if they are not able to detect small changes in health status within cancer patients. This raises concerns regarding the appropriateness of these instruments when comparing different cancer treatments within an economic evaluation framework.

Development of the EXACT-U: a preference-based measure to report COPD exacerbation utilities

BACKGROUND

The exacerbations of chronic obstructive pulmonary disease tool (EXACT) is a condition-specific daily diary recently developed to evaluate the frequency, severity, and duration of chronic obstructive pulmonary disease (COPD) exacerbations. A preference-based algorithm for the EXACT would allow utilities to be reported from patients during an exacerbation when EQ-5D data are not available.

OBJECTIVE

To develop the exacerbations of chronic obstructive pulmonary disease tool-utility (EXACT-U), a condition-specific preference-based measure to report utilities from the EXACT for use in cost-effectiveness studies.

METHODS

Five items with three to five levels comprise the EXACT-U. Two groups of health states and respondents were constructed to allow for model development (Development group) and predictive validity testing (Validation group) using independent samples. Members of the UK general public each valued 11 randomized health states using time trade-offs (TTOs) scaled from full health/dead with 10-year durations. Regression models estimated from the Development group using individual data, mean data, and panel designs. Models assessed by number of inconsistent coefficients estimated and R(2) and tested against observed utilities from the Validation group using mean absolute error (MAE) and root mean squared error (RMSE).

RESULTS

A total of 55 health states, including the best and worst states, were valued in TTO interviews conducted with 400 respondents. Ten models were developed. The final preferred model contained no logical inconsistencies and found MAE = 0.04 and RMSE = 0.05 with a predicted utility range from 0.09 to 0.95.

CONCLUSIONS

The EXACT-U is a condition-specific preference-based measure with strong predictive validity to report daily utilities during an exacerbation.

Estimating importance weights for the IWQOL-Lite using conjoint analysis

PURPOSE

Our objective was to estimate preference-based weights for the IWQOL-Lite that reflect the relative importance overweight and obese people place on the domains included in the instrument.

METHODS

US residents, 18 years of age or older, who are overweight (BMI=25.0-29.9) or obese (BMI>or=30) completed an online survey instrument consisting of 12 choice questions. The survey included eight attributes: problems doing usual daily activities, physical symptoms, worry about health, low self-esteem, sexual problems, problems moving around or sitting in public places, teasing or discrimination, and problems at work. Ordered probit was used to estimate importance weights for the attributes and levels.

RESULTS

Five hundred and two subjects completed the survey. Sexual problem was the most important attribute. The remaining attributes can be ranked on the order of importance as follows: low self-esteem, physical symptoms, daily activities, teasing or discrimination, moving around or sitting, problems at work, and worry about health.

CONCLUSIONS

Our results confirm previous findings that weighting the individual items in the IWQOL-Lite by the importance of outcomes to overweight and obese subjects may provide a more meaningful evaluation of the effect of changes in weight on patient well-being than a nonpreference-based measure of HRQOL.

The use of disease-specific outcome measures in cost-utility analysis: the development of Dutch societal preference weights for the FACT-L scale

INTRODUCTION

The Functional Assessment of Cancer Therapy-Lung (FACT-L) is a validated, sensitive and reliable patient questionnaire that evaluates and quantifies quality of life (QOL) across several domains, including lung cancer-related symptoms. The FACT-L was not designed for use in economic evaluation and does not incorporate preferences into its scoring system.

OBJECTIVE

To derive a set of Dutch preference weights for FACT-L health states that can be used to convert FACT-L into a single value that can be used in cost-utility analyses.

METHODS

A representative sample of the Dutch population (n = 1076) directly valued an orthogonal set of eight FACT-L health states on a 100-point rating scale with the anchor points 'worst imaginable health state' and 'best imaginable health state'. Eleven FACT-L items were selected to describe the FACT-L health states that were directly valued. Regression analysis was used to interpolate values for all other possible health states. Scores were transformed into values on a scale where 0 indicated dead and 1 indicated full health.

RESULTS

The estimated values for FACT-L health states ranged from 0.08 to 0.93. The estimated value sets were applied to FACT-L data of lung cancer patients participating in a clinical study. Significant differences in the mean value and mean gain of 0.12 and 0.07, respectively, were found between patients in remission and patients with progressive disease at 4 weeks' follow-up.

CONCLUSION

Our results reaffirmed that the methodology used here is a feasible option to convert data collected with a disease-specific outcome measure into preferences. We concluded that the sensitivity of the derived set of societal preferences to capture differences and changes in clinical health states is an indication of its construct validity.

Using the effect size to model change in preference values from descriptive health status

OBJECTIVES

This pilot study describes a modelling approach to translate group-level changes in health status into changes in preference values, by using the effect size (ES) to summarize group-level improvement.

METHODS

ESs are the standardized mean difference between treatment groups in standard deviation (SD) units. Vignettes depicting varying severity in SD decrements on the SF-12 mental health summary scale, with corresponding symptom severity profiles, were valued by a convenience sample of general practitioners (n = 42) using the rating scale (RS) and time trade-off methods. Translation factors between ES differences and change in preference value were developed for five mental disorders, such that ES from published meta-analyses could be transformed into predicted changes in preference values.

RESULTS

An ES difference in health status was associated with an average 0.171-0.204 difference in preference value using the RS, and 0.104-0.158 using the time trade off.

CONCLUSIONS

This observed relationship may be particular to the specific versions of the measures employed in the present study. With further development using different raters and preference measures, this approach may expand the evidence base available for modelling preference change for economic analyses from existing data.

Estimating a preference-based single index for the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) instrument from the SF-6D

OBJECTIVE

To facilitate economic evaluations of interventions for treating obesity, we estimated a preference-based single index for the Impact of Weight on Quality of Life-Lite (IWQOL-lite) instrument by mapping it onto the SF-6D preference-based index.

METHODS

A heterogeneous sample of 1972 individuals, composed of community volunteers and participants in weight loss programs, clinical trials, and gastric bypass studies, completed the IWQOL-lite, an obesity-specific measure of health-related quality of life (HRQOL), and the SF-36, a generic measure of HRQOL converted into the preference-based SF-6D. Models of the relationship between the IWQOL-lite and SF-6D of increasing complexity were estimated by regression analyses.

RESULTS

The best fitting model for predicting SF-6D index scores entered levels for each item as independent variables (R2 =0.530 in the cross-validation sample, with a mean absolute error of 0.0976). This model (1) makes fewer assumptions than those using total score, dimension scores or item scores as dependent variables and (2) provides a robust unbiased estimate of a preference-based index from IWQOL-Lite data where a preference-based measure was not used. The addition of age and body mass index (BMI) led to a slight improvement in the model.

CONCLUSIONS

It is possible to facilitate economic evaluations using results obtained from disease-specific instruments using this approach. A weakness of this approach is that there may be aspects of the condition that have not been properly reflected in the SF-6D index. It is, however, useful when a preference-based measure has not been administered and when it would be impractical to conduct a full valuation survey.

Reducing the burden of affective disorders: is evidence-based health care affordable?

BACKGROUND

Affective disorders remain the leading cause of disability burden despite the availability of efficacious treatment. A wider dissemination of evidence-based health care is likely to impact this burden, however the affordability of such a strategy at the population level is unknown. This study calculated the cost-effectiveness of evidence-based health care for depression, dysthymia and bipolar disorder in the Australian population, and determined whether it was affordable, based on current mental health-related expenditure and outcomes for these disorders.

METHODS

Cost-effectiveness was expressed in costs per years lived with disability (YLDs) averted, a population health summary measure of disability burden. Data from the Australian National Survey of Mental Health and Wellbeing, in conjunction with published randomized trials and direct cost estimates, were used to estimate the 1-year costs and YLDs averted by current health care services, and costs and outcomes for an optimal strategy of evidence-based health care.

RESULTS

Current direct mental health-related health care costs for affective disorders in Australia were 615 million dollars (1997-98 Australian dollars). This treatment averted just under 30,000 YLDs giving a cost-effectiveness ratio of 20,633 dollars per YLD. Outcome could be increased by nearly 50% at similar cost with implementation of an evidence-based package of optimal treatment, halving the cost-effectiveness ratio to 10,737 dollars per YLD.

LIMITATIONS

The method to estimate YLDs averted from the literature requires replication. The costs of implementing evidence-based health care have not been estimated.

CONCLUSIONS

Evidence-based health care for affective disorders should be encouraged on both efficacy and efficiency grounds.

Validity and feasibility of the use of condition-specific outcome measures in economic evaluation

BACKGROUND

Usually, generic questionnaires such as the EQ-5D or Health Utility Index (HUI) are used to obtain utility scores for computing QALYs. Sometimes, however, application of these instruments is not possible, or the responsiveness is doubted. An alternative strategy is to attribute utility scores to health states of a condition-specific outcomes measure (CSOM). We explored the validity and feasibility of this strategy.

RESEARCH DESIGN

Our samples determined utility scores for the health states of the International Index of Erectile Function (IIEF) using time tradeoff (TTO). To reduce costs and time, the general population (n = 169) was interviewed in groups. We tested the validity of the group sessions in students. To test the extent of agreement between values obtained using the group and those obtained through individual administration, 63 students were interviewed individually and 54 in groups.

RESULTS

The utility scores for the disease-specific health states showed good construct validity. Also, the criterion validity of the adapted TTO was confirmed.

DISCUSSION

Disease-specific utility scores can be used in QALY analysis by converting them to a generic scale. Efforts should be undertaken to prevent response spreading. Administrating TTO in groups could reduce the time and costs of TTO administration and render the strategy of determining utilities for condition-specific health states more feasible.

Decision validity should determine whether a generic or condition-specific HRQOL measure is used in health care decisions

When a HRQOL measure is needed in health care decision making should it be a generic measure (a GEN), intended to cover the entire domain of health, a condition-specific measure (a CSM) intended to embrace those aspects of health associated with the condition concerned, or both? This paper proposes that it will never be appropriate to use both a CSM and a GEN for the same decision; that a GEN alone will probably be the appropriate measure in the majority of decisions; that a CSM alone will sometimes be appropriate; and that whether it is a GEN alone or a CSM alone that is appropriate depends entirely on the structure of the decision. The argument rests on the distinction between knowledge validity and decision validity. But it has a supplementary basis in rejection of the widespread (but unjustifiable) belief that CSMs are more "sensitive" or "responsive" than GENs and hence can detect "small but important changes" that GENs always or often miss.

Health-related quality of life research and the capability approach of Amartya Sen

Standardised health-related quality of life questionnaires play an increasing role as measures of outcome in the evaluation of health care interventions. However, problems can arise when the selected functions or dimensions of such standardised measures are not in line with the intervention that is the focus of the research. Furthermore, the subjective element of quality of life makes standardised questionnaires vulnerable to the coping mechanism, thereby decreasing their sensitivity. The capability approach of the economist and philosopher Amartya Sen offers a descriptive concept that contributes to a better understanding of these problems. This article provides an introduction to the ideas of Sen for researchers who wish to go beyond the traditional framework of measuring health-related quality of life.

The effect of individually assessed preference weights on the relationship between holistic utilities and nonpreference-based assessment

In the assessment of health-related quality of life, nonpreference-based methods usually show only moderate correlations with utility-based measures. One cause may be that patients assign different weights to the various domains of health-related quality of life, for which nonpreference-based methods usually do not allow. Utilities reflect a weighted sum of these domains. The aim of this study is to assess whether the relationship between utility-based methods and nonpreference-based measures improves through the use of individual importance weights for the various domains of health-related quality of life. For this purpose, weights were obtained from 41 early-stage breast cancer patients, both before and during treatment, for seven pre-selected health status attributes representing important domains of health-related quality of life during chemotherapy. The importance weights were combined with the level of functioning on the attributes. These scores were regressed against patients' utilities for their actually experienced health state during chemotherapy, measured by means of a visual analog scale (VAS), a time trade-off (TTO), and a standard gamble (SG). Before weighting, the seven attribute scores were more strongly related to TTO and SG utilities than the nonpreference-based questionnaires. However, when they were combined with the importance weights, only the correlation with the SG utilities improved, and only so with the importance weights obtained before chemotherapy. In this study, assigning individually assessed preference weights to self-reported level of functioning did not result in stronger relationships with utilities.

Measuring population health: correlates of the Health Utilities Index among English and French Canadians

This study used cross-sectional data from the 1994/95 National Population Health Survey (NPHS) in Canada. The objective of the study was to examine the relationship between several established correlates of health status in the general population and the Health Utilities Index (HUI), a multi-dimensional, preference-based measure of health status. Analyses were carried out separately for the English-speaking (n = 9,853) and French-speaking (n = 1,519) respondents. The index correlated strongly with self-ratings of health status and functional disability and varied as expected according to age, sex, and income. Subjects classified to different categories of chronic conditions reported different levels of health, as predicted. The HUI was also associated with the use of drugs and recent history of hospitalization. No major differences in the findings were observed between the two cultural groups. The results should be treated with caution due to the cross-sectional design and other methodological limitations of the study.

Quality of life measurement clarifies the cost-effectiveness of Helicobacter pylori eradication in peptic ulcer disease and uninvestigated dyspepsia

OBJECTIVES

Previous economic studies of Helicobacter pylori eradication in dyspepsia and peptic ulcer disease have not measured quality of life using utilities (preference probabilities), which are needed to compare the cost-effectiveness of such treatment to other health care interventions. The goals of this study were to measure quality of life in patients with dyspepsia or peptic ulcer and apply these measurements to published models of disease management to determine cost-effectiveness in dollars per quality-adjusted life year (QALY) gained.

METHODS

Utilities for dyspepsia and peptic ulcer disease were measured in adult patients (n = 73) on chronic acid suppression for peptic ulcer or ulcer-like dyspepsia. Median utility values were applied to the results of published cost-effectiveness analyses and a previously validated dyspepsia model. Cost-utility ratios for early H. pylori eradication in uninvestigated dyspepsia and peptic ulcer disease were then computed.

RESULTS

The total disutility, or lost quality of life, for an ulcer was 0.11 QALY, of which 0.09 QALY was attributed to dyspeptic symptoms. After these results were incorporated into published studies, cost-utility ratios for ulcer treatment varied from $3,100 to $12,500 per QALY gained, whereas estimates for uninvestigated dyspepsia management ranged from $26,800 to $59,400 per QALY. Sensitivity analyses indicated a range of $1,300 to $27,300 per QALY for management of duodenal ulcer and $15,000 to $129,700 per QALY for dyspepsia.

CONCLUSIONS

Strategies that emphasize early H. pylori eradication were cost-effective for patients with peptic ulcer and possibly cost-effective for patients with uninvestigated dyspepsia, relative to other medical interventions. Dyspeptic symptoms cause significant disutility that should be incorporated in future cost-effectiveness analyses of treatment strategies.

Guidelines for clinical research in complementary medicine

There are several stages in preparing clinical research studies. Stage 1 includes identifying the purpose of the inquiry and finding the essential financial resources. Careful thinking about the clinical practice to be investigated and the allocation of time for research is also necessary. Stage 2 involves assessing the feasibility of the study. Statistical decisions are best made before data are collected, and this means consultation with a statistician or methodologist. There has to be ethical approval from the cooperating institution. A thorough search of the literature is fundamental. In Stage 3, the final trial is designed, ethical approval obtained, and the proposal is submitted for funding. In the final stage, Stage 4, the trial is carried out, analyzed, and prepared for publication.

Assessment of quality of life in patients with cardiac disease: the role of psychosomatic medicine

OBJECTIVE

The measurement of quality of life has become important in evaluating new treatments of cardiac disease. This review focuses on definition and general concepts underlying quality of life in patients with cardiac disease, the ways in which it is measured, and the uses and limitations of quality-of-life measurement.

METHODS

A Medline search, from 1988 to 1998, was undertaken using the search terms "cardiovascular disease and quality of life" and "cardiovascular disease and health status." Results of clinical trials of cardiovascular therapies using quality-of-life instruments were not reviewed.

RESULTS

Quality of life is defined as "...the functional effect of an illness and its consequent therapy upon a patient, as perceived by the patient." Domains of quality of life include physical, mental, social, and occupational function; health perceptions; and symptoms of disease.

CONCLUSION

Psychosomatic medicine contributions to understanding patients' reactions to physical illness and injury may offer enhanced insight into assessment of health perceptions. Generic health profiles and cardiac-disease-specific quality-of-life measures would also be useful in psychosomatic investigations of personality, hostility, depression, and social isolation in patients with cardiac disease.

Quality of life instruments in oncology

The objective of this article is to aid clinicians in understanding the current state of the development and application of quality of life (QOL) instruments as outcome measures in cancer clinical research and practice. As a result of the achievements of the past two decades, the concept of QOL has been defined and many reliable and valid measurement tools have been developed. The two main approaches to QOL assessment, psychometric-based and utility-based, are discussed together with a brief description of the strategies for meaningful interpretation of QOL profiles. QOL measures in oncology have the potential to be used to study populations in randomised clinical trials, to aid patient-clinician interactions in routine practice and to support policy decision making and economic evaluation of healthcare provision.