Measuring preferences for cost-utility analysis: how choice of method may influence decision-making

Clinical, economic and humanistic burdens of skeletal-related events associated with bone metastases

Despite effective skeletal-related event (SRE)-limiting therapies such as zoledronic acid and denosumab, SREs continue to place a meaningful burden on patients, providers and payers. However, studies of SRE-related effects on clinical (i.e., survival), economic (i.e., cost per event) and humanistic (i.e., quality of life) outcomes often report results in a composite manner and frequently do not differentiate the effects by SRE-type (i.e., bone radiation, bone surgery, hypercalcemia, pathological fracture and spinal cord compression). Nevertheless, understanding the differential burdens of individual SRE types, which vary in severity and duration of effect, is an important consideration - particularly in pharmacoeconomic evaluations of SRE-limiting therapies. In this review of the clinical, economic and humanistic SRE burden, it was found that SRE types can be differentiated by these outcomes, although economic outcomes are far more frequently reported than clinical or humanistic.

Validity and responsiveness of EuroQol-5 dimension (EQ-5D) versus Short Form-6 dimension (SF-6D) questionnaire in chronic pain

BACKGROUND

Assessments of health-related quality of life and particularly utility values are important components of health economic analyses. Several instruments have been developed to measure utilities. However no consensus has emerged regarding the most appropriate instrument within a therapeutic area such as chronic pain. The study compared two instruments - EQ-5D and SF-6D - for their performance and validity in patients with chronic pain.

METHODS

Pooled data from three randomised, controlled clinical trials with two active treatment groups were used. The included patients suffered from osteoarthritis knee pain or low back pain. Differences between the utility measures were compared in terms of mean values at baseline and endpoint, Bland-Altman analysis, correlation between the dimensions, construct validity, and responsiveness.

RESULTS

The analysis included 1977 patients, most with severe pain on the Numeric Rating Scale. The EQ-5D showed a greater mean change from baseline to endpoint compared with the SF-6D (0.43 to 0.58 versus 0.59 to 0.64). Bland-Altman analysis suggested the difference between two measures depended on the health status of a patient. Spearmans rank correlation showed moderate correlation between EQ-5D and SF-6D dimensions. Construct validity showed both instruments could differentiate between patient subgroups with different severities of adverse events and analgesic efficacies but larger differences were detected with the EQ-5D. Similarly, when anchoring the measures to a disease-specific questionnaire - Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) - both questionnaires could differentiate between WOMAC severity levels but the EQ-5D showed greater differences. Responsiveness was also higher with the EQ-5D and for the subgroups in which improvements in health status were expected or when WOMAC severity level was reduced the improvements with EQ-5D were higher than with SF-6D.

CONCLUSIONS

This analysis showed that the mean EQ-5D scores were lower than mean SF-6D scores in patients with chronic pain. EQ-5D seemed to have higher construct validity and responsiveness in these patients.

Valuing benefits to inform a clinical trial in pharmacy : do differences in utility measures at baseline affect the effectiveness of the intervention?

BACKGROUND

The generic health-related quality-of-life (HR-QOL) utility measures the EQ-5D and SF-6D are both commonly used to inform healthcare policy developments. However, their application to pharmacy practice is limited and the optimal method to inform policy developments is unknown.

OBJECTIVES

Our objective was to test the sensitivity of the EQ-5D and SF-6D within pharmacy when measuring whether changes in health status or other co-variates at baseline affect the effectiveness of the intervention at follow-up. A further objective was to consider the implications of the findings for pharmacy research and policy.

METHODS

The EQ-5D and SF-6D utility measures were employed within a randomized controlled trial (RCT) of community pharmacy-led medicines management for patients with coronary heart disease. The intervention covered a baseline visit with the potential for follow-up. Simultaneous quantile regression assessed the impact of the intervention on both EQ-5D and SF-6D measures at follow-up, controlling for baseline health, appropriateness of treatment, personal characteristics and self-reported satisfaction.

RESULTS

No statistically significant difference in HR-QOL across the intervention and control groups at follow-up was reported for either measure. Increased health gain was however associated with the baseline utility score (with the EQ-5D more sensitive for those in worse health) and the appropriateness of treatment, but not patient characteristics or self-reported satisfaction.

CONCLUSION

Neither generic measure detected a gain in HR-QOL as a result of the introduction of an innovative pharmacy-based service. This finding supports other work in the area of pharmacy, where health gains have not changed following interventions. Disease-specific utility measures should be investigated as an alternative to generic approaches such as the EQ-5D and SF-6D. Given that the RCT found an increase in self-reported satisfaction, broader measures of benefit that value patient experiences, such as contingent valuation and discrete-choice experiments, should also be considered in pharmacy.

Preference-based health-related quality-of-life outcomes in children with autism spectrum disorders: a comparison of generic instruments

BACKGROUND

Cost-effectiveness analysis of pharmaceutical and other treatments for children with autism spectrum disorders (ASDs) has the potential to improve access to services by demonstrating the value of treatment to public and private payers, but methods for measuring QALYs in children are under-studied. No cost-effectiveness analyses have been undertaken in this population using the cost-per-QALY metric.

OBJECTIVE

This study describes health-related quality-of-life (HR-QOL) outcomes in children with ASDs and compares the sensitivity of two generic preference-based instruments relative to ASD-related conditions and symptoms.

METHODS

The study design was cross-sectional with prospectively collected outcome data that were correlated with retrospectively assessed clinical information. Subjects were recruited from two sites of the Autism Treatment Network (ATN) in the US: a developmental centre in Little Rock, Arkansas, and an outpatient psychiatric clinic at Columbia University Medical Center in New York. Children that met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for an ASD by a multidisciplinary team evaluation were asked to participate in a clinical registry. Families of children with an ASD that agreed to be contacted about participation in future research studies as part of the ATN formed the sampling frame for the study. Families were included if the child with the ASD was between 4 and 17 years of age and the family caregiver spoke English. Eligible families were contacted by mail to see if they would be interested in participating in the study with 150 completing surveys. HR-QOL outcomes were described using the Health Utilities Index (HUI) 3 and the Quality of Well-Being Self-Administered (QWB-SA) scale obtained by proxy via the family caregiver.

RESULTS

Children were diagnosed as having autistic disorder (76%), pervasive developmental disorder-not otherwise specified [PDD-NOS] (15%), and Asperger's disorder (9%). Average HUI3 and QWB-SA scores were 0.68 (SD 0.21, range 0.07-1) and 0.59 (SD 0.16, range 0.18-1), respectively. The HUI3 score was significantly correlated with clinical variables including adaptive behaviour (ρ = 0.52; p < 0.001) and cognitive functioning (ρ = 0.36; p < 0.001). The QWB-SA score had weak correlation with adaptive behaviour (ρ = 0.25; p < 0.001) and cognitive functioning (ρ = 0.17; p < 0.005). Change scores for the HUI3 were larger than the QWB-SA for all clinical measures. Scores for the HUI3 increased 0.21 points (95% CI 0.14, 0.29) across the first to the third quartile of the cognitive functioning measure compared with 0.05 (95% CI -0.01, 0.11) for the QWB-SA. Adjusted R2 values also were higher for the HUI3 compared with the QWB-SA across all clinical measures.

CONCLUSIONS

The HUI3 was more sensitive to clinical measures used to characterize children with autism compared with the QWB-SA score. The findings provide a benchmark to compare scores obtained by alternative methods and instruments. Researchers should consider incorporating the HUI3 in clinical trials and other longitudinal research studies to build the evidence base for describing the cost effectiveness of services provided to this important population.

SF-6D and EQ-5D result in widely divergent incremental cost-effectiveness ratios in a clinical trial of older women: implications for health policy decisions

SUMMARY

Using two instruments (SF-6D and EQ-5D) to estimate quality adjusted life years (QALYs), we conducted an economic evaluation of a 12-month randomized controlled trial with a 12-month follow-up study in older women to evaluate the value for money of two doses of resistance training compared with balance and tone classes. We found that the incremental QALYs estimated from the SF-6D were two- to threefold greater than those estimated from the EQ-5D.

INTRODUCTION

Decision makers must continually choose between existing and new interventions. Hence, economic evaluations are increasingly prevalent. The impact of quality-adjusted life year (QALY) estimates using different instruments on the incremental cost-effectiveness ratios (ICERs) is not well understood in older adults. Thus, we compared ICERs, in older women, estimated by the EuroQol-5D (EQ-5D) and the Short Form-6D (SF-6D) to discuss implications on decision making.

METHODS

Using both the EQ-5D and the SF-6D, we compared the incremental cost per QALY gained in a randomized controlled trial of resistance training in 155 community-dwelling women aged 65 to 75 years. The 12-month randomized controlled trial included a subsequent 12-month follow-up. Our focus, the follow-up study, included 123 of the 155 participants from the Brain Power study; 98 took part in the economic evaluation (twice-weekly balance and tone exercises, n = 28; once-weekly resistance training, n = 35; twice-weekly resistance training, n = 35). Our primary outcome measure was the incremental cost per QALY gained of once- or twice-weekly resistance training compared with balance and tone exercises.

RESULTS

At cessation of the follow-up study, the incremental QALY was -0.051 (EQ-5D) and -0.144 (SF-6D) for the once-weekly resistance training group and -0.081 (EQ-5D) and -0.127 (SF-6D) for the twice-weekly resistance training group compared with balance and tone classes.

CONCLUSION

The incremental QALYs estimated from the SF-6D were two- to threefold greater than those estimated from the EQ-5D. Given the large magnitude of difference, the choice of preference-based utility instrument may substantially impact health care decisions.

QALY weights for diabetic retinopathy--a comparison of health state valuations with HUI-3, EQ-5D, EQ-VAS, and TTO

OBJECTIVE

To estimate quality-adjusted life-year weights for patients with diabetic retinopathy by using various methods and to investigate the empirical validity of the different measures.

METHODS

The study population comprised 152 patients with diabetes in Östergötland County, Sweden. Participants were interviewed by telephone by using the time trade-off (TTO) method and a visual analogue scale (EQ-VAS) (direct valuations) as well as the EuroQol five-dimensional questionnaire (EQ-5D) and the health utilities index mark 3 (HUI-3) (indirect valuations). The quality-adjusted life-year weights were adjusted for potential confounders by using analysis of covariance. The empirical validity of the measures was examined by testing their ability to detect hypothetical differences between severity levels of diabetic retinopathy and by investigating the correlation between the measures and the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25).

RESULTS

All measures detected significant differences in scores between patient groups classified according to visual impairment in the better eye (analysis of covariance, P < 0.05), but only HUI-3 and EQ-VAS detected significant differences between patient groups classified according to visual impairment or pathological progression in the worse eye. HUI-3 recorded a difference of 0.43 in values between normal vision and blindness in the better eye, which was more than twice the differences captured by the other measures (0.15-0.20). In addition, HUI-3 showed the highest correlation with NEI VFQ-25 (r = 0.54; P < 0.001).

CONCLUSIONS

In cost-utility analyses, the choice of quality-adjusted life-year measure may affect whether an intervention is considered cost-effective. Furthermore, if decisions are to be based on values from the general public, HUI-3 can be recommended for cost-utility analyses of interventions directed at diabetic retinopathy.

Pharmacoeconomics of bisphosphonates for skeletal-related event prevention in metastatic non-breast solid tumours

Bisphosphonates reduce the risk of skeletal-related events (SREs; i.e. spinal cord compression, pathological fracture, radiation or surgery to the bone, and hypercalcaemia) in patients with metastatic cancer. A number of analyses have been conducted to assess the cost effectiveness of bisphosphonates in patients with bone metastases secondary to breast cancer, but few in other solid tumours. This is a review of cost-effectiveness analyses in patients with non-breast solid tumours and bone metastases. A literature search was conducted to identify cost-effectiveness analyses reporting the cost per QALY gained of bisphosphonates in patients with metastatic bone disease secondary to non-breast solid tumours. Four analyses met inclusion criteria. These included two in prostate cancer (one of which used a global perspective but expressed results in $US, and the other reported from a multiple country perspective: France, Germany, Portugal and the Netherlands). The remaining analyses were in lung cancer (in the UK, France, Germany, Portugal and the Netherlands), and renal cell carcinoma (in the UK, France and Germany). In each analysis, the cost effectiveness of zoledronic acid versus placebo was analysed. Zoledronic acid was found to be cost effective in all European countries across all three indications but not in the sole global prostate cancer analysis. Across countries and indications, assumptions regarding patient survival, drug cost and baseline utility (i.e. patient utility with metastatic disease but without an SRE) were the most robust drivers of modelled estimates. Assumptions of SRE-related costs were most often the second strongest cost driver. Further review indicated that particular attention should be paid to the inclusion or exclusion of nonsignificant survival benefits, whether health state utilities were elicited from community or patient samples or author assumptions, delineation between symptomatic and asymptomatic SREs, and the methods with which SRE disutility was modelled over time. While the field of cost-effectiveness analysis in solid tumours other than breast cancer is still evolving, outcomes will likely continue to be driven by drug cost and assumptions regarding treatment benefits. Although considerations such as adverse events and administration costs are important, they were not found to influence cost-effectiveness estimates greatly. As zoledronic acid will lose patent protection in 2013 and subsequently be greatly reduced in price, it is likely that the field of cost effectiveness will change with regard to SRE-limiting agents. Meanwhile, research should be conducted to improve our understanding of the impact on quality of life and medical costs of preventing SREs.

Estimating utilities for chronic kidney disease, using SF-36 and SF-12-based measures: challenges in a population of veterans with diabetes

PURPOSE

Using transformations of existing quality-of-life data to estimate utilities has the potential to efficiently provide investigators with utility information. We used within-method and across-method comparisons and estimated disutilities associated with increasing chronic kidney disease (CKD) severity.

METHODS

In an observational cohort of veterans with diabetes (DM) and pre-existing SF-36/SF-12 responses, we used six transformation methods (SF-12 to EQ-5D, SF-36 to HUI2, SF-12 to SF-6D, SF-36 to SF-6D, SF-36 to SF-6D (Bayesian method), and SF-12 to VR-6D) to estimate unadjusted utilities. CKD severity was staged using glomerular filtration rate estimated from serum creatinines, with the modification of diet in renal disease formula. We then used multivariate regression to estimate disutilities specifically associated with CKD severity stage.

RESULTS

Of 67,963 patients, 22,273 patients had recent-onset DM and 45,690 patients had prevalent DM. For the recent-onset group, the adjusted disutility associated with CKD derived from the six transformation methods ranged from 0.0029 to 0.0045 for stage 2; -0.004 to -0.0009 for early stage 3; -0.017 to -0.010 for late stage 3; -0.023 to -0.012 for stage 4; -0.078 to -0.033 for stage 5; and -0.012 to -0.001 for ESRD/dialysis.

CONCLUSION

Disutility did not increase monotonically as CKD severity increased. Differences in disutilities estimated using the six different methods were found. Both findings have implications for using such estimates in economic analyses.

Predicting EQ-5D-US and SF-6D societal health state values from the Osteoporosis Assessment Questionnaire

SUMMARY

Linear regression was applied to data from 275 persons with osteoporosis-related fracture to estimate EQ-5D-US and SF-6D health state values from the Osteoporosis Assessment Questionnaire. The models explained 56% and 58% of the variance in scores, respectively, and root mean square error values (0.096 and 0.085) indicated adequate prediction for use when actual values are unavailable.

INTRODUCTION

This study was conducted to provide models that predict EQ-5D-US and SF-6D societal health state values from the Osteoporosis Assessment Questionnaire (OPAQ).

METHODS

OPAQ, EQ-5D, and SF-6D data from individuals at two centers with prior osteoporosis-related fracture were used. Fractures were classified by type as hip/hip-like, spine/spine-like, or wrist/wrist-like. Spearman rank correlations between preference-based system (EQ-5D and SF-6D) dimensions and OPAQ subscales were estimated. Linear regression was used to estimate preference-based system health state values based on OPAQ subscales. We assessed models including age, sex, and fracture type and chose the model with the best performance based on the root mean square error (RMSE) estimate.

RESULTS

Among the 275 participants (198 women), with mean age of 68 years (range 50-94), the distribution of fracture types included 10% hip/5% hip-like, 18% spine/11% spine-like, and 24% wrist/18% wrist-like. The final regression model for EQ-5D-US included three OPAQ attributes (physical function, emotional status, and symptoms), predicted 56% of the variance in EQ-5D-US scores, and had a RMSE of 0.096. The final model for SF-6D, which included all four OPAQ dimensions, predicted 58% of the variance in SF-6D scores and had a RMSE of 0.085.

CONCLUSIONS

Two models were developed to estimate EQ-5D-US and SF-6D health state values from OPAQ and demonstrated adequate prediction for use when actual values are not available.

The development of a model for translation of the Neck Disability Index to utility scores for cost-utility analysis in cervical disorders

BACKGROUND CONTEXT

The Neck Disability Index (NDI) is a commonly used disease-specific instrument for cervical spine disorders with good responsiveness and psychometric properties compared with general health status measures. However, NDI scores are unitless and do not have an intrinsic value that is comparable to other health status measures, and these scores have limited value in cost-utility analysis. The translation of disease-specific measures to Short Form-6 Dimensions (SF-6D) utility scores may be useful in cost-utility analysis.

PURPOSE

The purpose of this study is to present a model for translating the NDI to SF-6D utility scores, permitting the use of NDI scores in the cost-utility analysis of cervical disorders.

STUDY DESIGN/SETTING

A secondary analysis of a multicenter prospective clinical trial of the Synthes ProDisc-C (Synthes, West Chester, PA, USA) was performed.

PATIENT SAMPLE

Patients included were randomized to receive either a total disc arthroplasty or anterior cervical discectomy and fusion for treatment of symptomatic cervical disc disease involving one vertebral level between C3 and C7. All subjects completed NDI and 36-Item Short Form Health Survey (SF-36) self-assessments at preoperative and postoperative follow-ups of 6 weeks, 3, 6, 12, 18, and 24 months.

OUTCOME MEASURES

The NDI is a validated and widely used self-reported questionnaire designed to assess patient-determined disability resulting from neck pain, including pain level and effects on activities of daily living. The SF-6D is a preference-based health state classification system derived from six health dimensions of the SF-36 self-reported questionnaire, including the domains of physical functioning, role limitation, social functioning, bodily pain, mental health, and vitality.

METHODS

The collected data points were divided into two cohorts: one for model formation and one for the assessment of model validity. SF-36 scores were converted to SF-6D utilities via three previously published methods. Correlation analyses and linear regression modeling between SF-6D and NDI created the models for translating scores. For validation, Spearman and Pearson correlations were calculated between the observed and predicted SF-6D utilities, and prediction errors were calculated.

RESULTS

Four hundred thirty patients with 2,137 time points were used for creation and validation of the model. Pearson and Spearman correlation coefficients between the NDI and the SF-6D derived from each conversion method were found to be between -0.8255 and -0.8504 (p<.01). R(2) values ranged from 0.68 to 0.71 and root mean squared error (RMSE) from 0.092 to 0.084. Correlations between estimated and observed SF-6D scores ranged from 0.8325 to 0.8372 (p<.01). The mean prediction error was less than 0.006, with standard deviation (SD) between 0.082 and 0.093.

DISCUSSION

Correlations between NDI and SF-6D utility scores are strong and statistically significant. The model has a large R(2) and small RMSE. The prediction models produce a small mean prediction error, but the SD of the prediction errors is large. High correlations between NDI and SF-6D permit these models to be used to calculate overall utilities, changes in utilities, and quality-adjusted life-years for large data samples. However, the relatively large observed prediction error SDs may limit the accuracy of translation of individual data points or small sample sizes.

Utility values for chronic myelogenous leukemia chronic phase health states from the general public in the United Kingdom

This study estimated time trade-off preference values associated with the four chronic myelogenous leukemia (CML) chronic phase-related health states (i.e. untreated, hematologic response, cytogenetic response and molecular response) among members of the general public in the UK (n = 241). All four health states were associated with decreases in preference values from full health. The molecular response to treatment was the most preferred health state (mean utility of 0.94). The second-most preferred health state was cytogenetic response followed by hematologic response (mean utilities were 0.89 and 0.80, respectively). The least preferred health state was untreated chronic phase CML (mean utility of 0.72). The utility values for each state were significantly different from one another (p < 0.001). This study demonstrated and quantified the impact that more robust treatment responses have on the health-related quality of life of patients with chronic phase CML.

Systematic Review and Empirical Comparison of Contemporaneous EQ-5D and SF-6D Group Mean Scores

Background. Group mean estimates and their underlying distributions are the focus of assessment for cost and outcome variables in economic evaluation. Research focusing on the comparability of alternative preference-based measures of health-related quality of life has typically focused on analysis of individual-level data within specific clinical specialties or community-based samples. Purpose. To explore the relationship between group mean scores for the EQ-5D and SF-6D across the utility scoring range. Methods. Studies were identified via a systematic search of 13 online electronic databases, a review of reference lists of included papers, and hand searches of key journals. Studies were included if they reported contemporaneous mean EQ-5D and SF-6D health state scores. All (sub)group comparisons of group mean EQ-5D and SF-6D scores identifiable from text, tables, or figures were extracted from identified studies. A total of 921 group mean comparisons were extracted from 56 studies. The nature of the relationship between the paired scores was examined using ranked scatter graphs and analysis of agreement. Results. Systematic differences in group mean estimates were observed at both ends of the utility scale. At the lower (upper) end of the scale, the SF-6D (EQ-5D) provides higher mean utility estimates. Conclusions. These findings show that group mean EQ-5D and SF-6D scores are not directly comparable. This raises serious concerns about the cross-study comparability of economic evaluations that differ in the choice of preference-based measures, although the review focuses on 2 of the available instruments only. Further work is needed to address the practical implications of noninterchangeable utility estimates for cost-per-QALY estimates and decision making.

Is the United States ready for QALYs?

Quality-adjusted life-years (QALYs) are used in cost-effectiveness analyses to aid coverage and reimbursement decisions worldwide. QALYs provide a flexible and convenient metric for measuring and comparing health outcomes across diverse diseases and treatments. But their use has stirred controversy about how accurately they reflect preferences for health care and whether their use is fair. We review the debate and the use of QALYs in other countries and discuss prospects for using them in the U.S. health care system. Strict adherence to a QALY approach is likely to prove unacceptable in the United States, but a more flexible use of QALYs could be beneficial.

Using the knee-specific Hughston Clinic Questionnaire, EQ-5D and SF-6D following arthroscopic partial meniscectomy surgery: a comparison of psychometric properties

PURPOSE

To compare the psychometric properties of the Hughston Clinic Questionnaire (HCQ), EQ-5D and SF-6D in patients following arthroscopic partial meniscectomy surgery.

METHODS

A total of 84 participants (86% men; mean age 40) were recruited. The questionnaires were completed on average 5 days, 6 weeks and 6 months after surgery and compared for internal consistency, convergent validity, sensitivity to change and floor and ceiling effects.

RESULTS

Internally, the HCQ was the most consistent instrument (α = 0.923) followed by the SF-6D and EQ-5D. The EQ-5D and SF-6D were moderately correlated with the HCQ (ρ = 0.499 and 0.394, respectively). Six weeks after surgery, the most sensitive measures were the HCQ and EQ-5D (effect size: 2.04 and 0.99, respectively), at 6 months, with a smaller cohort (n = 42), again it was the HCQ and EQ-5D (effect size: 2.03 and 1.04, respectively). The SF-6D demonstrated no ceiling or floor effect during the study; the HCQ demonstrated a ceiling affect for 5% of respondents at 6 months after surgery compared to 26% of respondents for the EQ-5D.

CONCLUSION

For this patient population, our findings indicated that the EQ-5D was more consistently responsive to change over time, as a utility index was better at distinguishing differences between groups and reflected the results of the joint-specific HCQ for knee recovery better than the SF-6D. It is therefore recommended that for similar populations, the EQ-5D is preferable to the SF-6D for utilisation alongside the HCQ.

[IQWiG's methods for the cost-benefit assessment : Comparison with an international reference scenario]

Standardization of international health economic guidelines has been repeatedly requested. In this context, an international reference case was proposed, which constitutes an agreed approach for the key elements of health economic evaluation including study perspective, comparators, source of effectiveness data, role of modeling, main (economic) outcome, source of utilities, characterizing uncertainty. It is, however, questionable whether such a reference scenario can reasonably be applied across all health care systems. Our analysis pursues the question to which degree the Institute for Quality and Efficiency in Health Care's (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen, IQWiG) "General methods for evaluating the relation between cost and benefit" comply with the key elements of the reference case. In case of divergences, they will be described and discussed in light of the German social legislation and in consideration of current scientific evidence. In conclusion, the analysis revealed that IQWiG complied with the reference case in almost all aspects. Differences were found only with respect to the choice of main (economic) outcome and the source of utilities. These differences seem justified and well explained in the context of the German social legislation as well as in view of the weaknesses of the quality-adjusted life year (QALY) concept.

The impact of differences in EQ-5D and SF-6D utility scores on the acceptability of cost-utility ratios: results across five trial-based cost-utility studies

OBJECTIVE

This article investigates whether differences in utility scores based on the EQ-5D and the SF-6D have impact on the incremental cost-utility ratios in five distinct patient groups.

METHODS

We used five empirical data sets of trial-based cost-utility studies that included patients with different disease conditions and severity (musculoskeletal disease, cardiovascular pulmonary disease, and psychological disorders) to calculate differences in quality-adjusted life-years (QALYs) based on EQ-5D and SF-6D utility scores. We compared incremental QALYs, incremental cost-utility ratios, and the probability that the incremental cost-utility ratio was acceptable within and across the data sets.

RESULTS

We observed small differences in incremental QALYs, but large differences in the incremental cost-utility ratios and in the probability that these ratios were acceptable at a given threshold, in the majority of the presented cost-utility analyses. More specifically, in the patient groups with relatively mild health conditions the probability of acceptance of the incremental cost-utility ratio was considerably larger when using the EQ-5D to estimate utility. While in the patient groups with worse health conditions the probability of acceptance of the incremental cost-utility ratio was considerably larger when using the SF-6D to estimate utility.

CONCLUSIONS

Much of the appeal in using QALYs as measure of effectiveness in economic evaluations is in the comparability across conditions and interventions. The incomparability of the results of cost-utility analyses using different instruments to estimate a single index value for health severely undermines this aspect and reduces the credibility of the use of incremental cost-utility ratios for decision-making.

Using qualitative methods to inform the trade-off between content validity and consistency in utility assessment: the example of type 2 diabetes and Alzheimer's disease

BACKGROUND

Key stakeholders regard generic utility instruments as suitable tools to inform health technology assessment decision-making regarding allocation of resources across competing interventions. These instruments require a 'descriptor', a 'valuation' and a 'perspective' of the economic evaluation. There are various approaches that can be taken for each of these, offering a potential lack of consistency between instruments (a basic requirement for comparisons across diseases). The 'reference method' has been proposed as a way to address the limitations of the Quality-Adjusted Life Year (QALY). However, the degree to which generic measures can assess patients' specific experiences with their disease would remain unresolved. This has been neglected in the discussions on methods development and its impact on the QALY values obtained and resulting cost per QALY estimate underestimated. This study explored the content of utility instruments relevant to type 2 diabetes and Alzheimer's disease (AD) as examples, and the role of qualitative research in informing the trade-off between content coverage and consistency.

METHOD

A literature review was performed to identify qualitative and quantitative studies regarding patients' experiences with type 2 diabetes or AD, and associated treatments. Conceptual models for each indication were developed. Generic- and disease-specific instruments were mapped to the conceptual models.

RESULTS

Findings showed that published descriptions of relevant concepts important to patients with type 2 diabetes or AD are available for consideration in deciding on the most comprehensive approach to utility assessment. While the 15-dimensional health related quality of life measure (15D) seemed the most comprehensive measure for both diseases, the Health Utilities Index 3 (HUI 3) seemed to have the least coverage for type 2 diabetes and the EuroQol-5 Dimensions (EQ-5D) for AD. Furthermore, some of the utility instruments contained items that could not be mapped onto either of the proposed conceptual models.

CONCLUSIONS

Content of the utility measure has a significant impact on the treatment effects that can be observed. This varies from one disease to the next and as such contributes to lack of consistency in observable utility effects and incremental utility scores. This observation appears to have been omitted from the method development considerations such as reference methods. As a result, we recommend that patients' perspectives obtained via qualitative methods are taken into consideration in the ongoing methods development in health state descriptions for generic utility instruments. Also, as a more immediate contribution to improving decision making, we propose that a content map of the chosen utility measure with patient-reported domains be provided as standard reporting in utility measurement in order to improve the transparency of the trade-offs in relation to patient relevance and consistency.

A multinational study of health state preference values associated with chronic myelogenous leukemia

OBJECTIVES

Chronic myelogenous leukemia (CML) is a progressive, largely fatal cancer. Emerging treatments may prolong life; however, these result in additional monetary costs. Accurate estimation of their economic impact requires reliable estimates on preferences for health states. The purpose was to estimate preference weights from the general population in four developed countries for standardized health states experienced by persons with CML.

METHODS

Time trade-off preferences with a 10-year time horizon were elicited for CML-related health states using an interviewer-administered survey from convenience samples in Canada (n=103), the United States (n=74), the UK (n=97), and Australia (n=79). Standardized descriptions of seven CML-related health states (characterizing chronic, accelerated and blast phases, each with responding and nonresponding state, and adverse events of treatment) were derived in consultation with oncologists. Generalized linear models were used to estimate whether utilities, adjusted for age and sex, differed by country.

RESULTS

The mean age of the sample (n=357) was 45 years and 46% were male. Mean unadjusted preference values of CML-related health states ranged from 0.84 for "Chronic phase responding to treatment" to 0.21 for "Blast phase, not responding to treatment." For each phase, preferences were lower for the nonresponding state. After adjustment for age and sex, considerable variability was observed in mean preference values between countries.

CONCLUSION

These data quantify the deteriorating impact of CML disease progression and the impact of nonresponse to treatment. The study results add to evidence from other disease areas that systematic differences exist in preference values between countries.

The classification systems of the EQ-5D, the HUI II and the SF-6D: what do they have in common?

PURPOSE

EQ-5D, HUI II and SF-6D often produce very different valuations for the same health state. This paper aims at clarifying to what extent this might be caused by differences between the multi-attribute classification systems belonging to these instruments.

METHODS

Subjects were 264 patients of rehabilitation clinics in Mecklenburg-Western Pomerania (44.3% female; mean age 49.1) who completed the EQ-5D, the HUI II and the SF-36 (the basis of the SF-6D). After scaling with principal component analyses for categorical data, each attribute of each classification system was regressed on the classification systems of the other two instruments, and all attributes together were subjected to ordinary principal component analysis with varimax rotation.

RESULTS

Adjusted multiple R(2) for regression analyses ranged from 0.01 to 0.57. The HUI II attribute 'sensation' and the SF-6D attribute 'role limitation' are virtually unrelated to the remainder. All other attributes of all three instruments can be predicted by each other. EQ-5D and HUI II focus distinctly more on physical functioning than SF-6D.

CONCLUSION

Although all three classification systems have a lot in common, they differ so much that EQ-5D, HUI II and SF-6D would produce different valuations even if these valuations were determined according to the same principle.

Interchangeability of the EQ-5D and the SF-6D in long-lasting low back pain

OBJECTIVES

The objective of this study was to investigate the interchangeability of the EuroQol 5D (EQ-5D) and the Short Form 6D (SF-6D) in individuals with long-lasting low back pain to guide the optimal choice of instrument and to inform decision-makers about any between-measure discrepancy, which require careful interpretation of the results of cost-utility evaluations.

METHODS

A cross-sectional study was conducted across 275 individuals who had spinal surgery on indication of chronic low back pain. EQ-5D and SF-6D were mailed to respondents for self-completion. Statistical analysis of between-measure agreement (using English weights) was based on Bland and Altman's limits of agreement and a series of linear regressions.

RESULTS

A moderate mean difference of 0.085 (SD 0.241) was found, but because it masked more severe bidirectional variation, the expected variation between observations of EQ-5D and SF-6D in future studies was estimated at 0.546. The EQ-5D's N3 term alone explained a factor of 0.79 of the variation in between-measure differences, while the explanatory value of adding variables of age, sex, diagnosis, previous surgery, and occupational status was basically zero. A final model including only dummy variables for the N3 term and five identified framing effects explained a factor of 0.86 of the variation in between-measure differences.

CONCLUSIONS

Although the EQ-5D and the SF-6D are both psychometrically valid for generic outcome assessment in long-lasting low back pain, it appears that they cannot generally be used interchangeably for measurement of preference values. Sensitivity analysis examining the impact of between-measure discrepancy thus remains a necessary condition for the interpretation of the results of cost-utility evaluations.

Breast cancer-related preferences among women with and without BRCA mutations

Preference ratings are used to quantify quality of life in analyses used for health care policy making. Subjects indicated how many years of their life expectancy they would trade to avoid BRCA mutations, breast/ovarian cancer, and five preventive measures including prophylactic surgery, annual mammograms, and annual magnetic resonance imaging (MRI). Among 243 respondents, both the 83 women with mutations and the 160 controls rated mammography highest (most favorably), MRI next highest, having a child with a mutation lowest, and ovarian cancer next lowest. Controls rated prophylactic surgery higher than cancer (P < 0.01), but women with mutations did not. In logistic regression, controls were twice as willing as women with mutations to trade time except for screening modalities; younger, lower-income, and non-white women were more willing to trade time than older, higher-income, and white women. Our findings support the use of average-risk individuals' time trade-off preference ratings for health care policy development.

The validity of EQ-5D US preference weights in liver transplant candidates and recipients

Health utility instruments assess patients' valuation of specific health states, which can be converted to quality-adjusted life years for cost-utility analysis. Data from the EQ-5D, a generic health-related quality of life questionnaire from EuroQoL, can be reported as 5 health status scores or as a single health preference weight (HPW). US population-based HPWs were published by Shaw and colleagues in 2005 (Med Care 2005;43:203-220). Our aim was to test the validity of US EQ-5D HPWs and health status scores in liver transplant patients. EQ-5D scores were converted to HPWs with Shaw et al.'s model. Data were stratified by measurement period: pretransplant period, early posttransplant period (< or =12 months), intermediate posttransplant period (13-36 months), and late posttransplant period (>36 months). EQ-5D scores were compared to specific, hypothesized Short Form 36 Health Survey, Center for Epidemiologic Studies Depression Scale, and Beck Anxiety Inventory scores that were identified a priori on the basis of construct similarity. Criterion-related and construct validity were tested with nonparametric methods. Two hundred eighty-five adults participated (113 in the pretransplant period, 60 in the early posttransplant period, 47 in the intermediate posttransplant period, and 65 in the late posttransplant period), and follow-up averaged 36 +/- 36 months. Eighty-one percent of the hypothesized relationships between EQ-5D and gold-standard scales were strong (r > or = |0.5|, P < 0.001), and the remainder were moderate (r > |0.3|, P < 0.001). Differences between pretransplant and posttransplant EQ-5D HPWs were statistically significant. In conclusion, EQ-5D dimensions and the health utility index generated from Shaw's US population preference weights demonstrated criterion-related and construct validity in liver transplant patients. It is a valid instrument for cost-utility analysis in this setting.

Utility assessment in patients with mental disorders: validity and discriminative ability of the time trade-off method

BACKGROUND

Preference-based health-state values, also referred to as utility scores, are considered an important measure of outcome in the evaluation of healthcare. A common approach to elicit utility scores is the use of the time trade-off (TTO) method; however, the data on TTO utility scores in patients with mental disorders are scarce.

OBJECTIVE

To analyse the TTO method in patients with mental disorders in terms of discriminative ability, validity and the refusal to trade life time (zero trade).

METHODS

In patients with affective (n = 172), schizophrenia spectrum (n = 166) and alcohol-related (n = 160) mental disorders, TTO utilities were administered through a standardized interview. Measures of quality of life (QOL) EQ-5D, WHOQOL-BREF, subjective (SCL-90R) and objective (CGI-S) psychopathology, and functioning (GAF, GARF, SOFAS, HoNOS) provided comparison. Discriminative ability was analysed by assessing frequency distributions of TTO utilities. Validity was analysed by assessing the correlation of TTO utilities with all other scores. The association of a patient's QOL, sociodemographic and disease-related variables with zero trade was analysed by logistic regression.

RESULTS

Of patients with affective/schizophrenic/alcohol-related mental disorders, 153/143/145 (89/86/91%), respectively, completed the TTO elicitation; 29/43/28% of the respondents were zero traders. The mean TTO utility was 0.66/0.75/0.61 and the median was 0.85/0.95/0.75. TTO utility scores discriminated well among more impaired mental health states, but discrimination was limited among less impaired health states. In patients with affective and alcohol-related mental disorders, TTO utility scores were significantly correlated (mostly moderate: 0.3 < r < 0.5) with all other scores. However, in schizophrenic patients, TTO utility scores were only a little correlated with other subjective measures and not correlated with objective measures. QOL was significantly associated with zero trade; the influence of the other variables on zero trade was negligible.

CONCLUSIONS

TTO utility scores in patients with affective or alcohol-related mental disorders were reasonably valid, but discriminative ability was compromised by a ceiling effect due to zero trade. In schizophrenic patients, validity of TTO utility scores was not demonstrated.

Current Status and Future Prospects of Clinical Psychology: Toward a Scientifically Principled Approach to Mental and Behavioral Health Care

The escalating costs of health care and other recent trends have made health care decisions of great societal import, with decision-making responsibility often being transferred from practitioners to health economists, health plans, and insurers. Health care decision making increasingly is guided by evidence that a treatment is efficacious, effective-disseminable, cost-effective, and scientifically plausible. Under these conditions of heightened cost concerns and institutional-economic decision making, psychologists are losing the opportunity to play a leadership role in mental and behavioral health care: Other types of practitioners are providing an increasing proportion of delivered treatment, and the use of psychiatric medication has increased dramatically relative to the provision of psychological interventions. Research has shown that numerous psychological interventions are efficacious, effective, and cost-effective. However, these interventions are used infrequently with patients who would benefit from them, in part because clinical psychologists have not made a convincing case for the use of these interventions (e.g., by supplying the data that decision makers need to support implementation of such interventions) and because clinical psychologists do not themselves use these interventions even when given the opportunity to do so. Clinical psychologists' failure to achieve a more significant impact on clinical and public health may be traced to their deep ambivalence about the role of science and their lack of adequate science training, which leads them to value personal clinical experience over research evidence, use assessment practices that have dubious psychometric support, and not use the interventions for which there is the strongest evidence of efficacy. Clinical psychology resembles medicine at a point in its history when practitioners were operating in a largely prescientific manner. Prior to the scientific reform of medicine in the early 1900s, physicians typically shared the attitudes of many of today's clinical psychologists, such as valuing personal experience over scientific research. Medicine was reformed, in large part, by a principled effort by the American Medical Association to increase the science base of medical school education. Substantial evidence shows that many clinical psychology doctoral training programs, especially PsyD and for-profit programs, do not uphold high standards for graduate admission, have high student-faculty ratios, deemphasize science in their training, and produce students who fail to apply or generate scientific knowledge. A promising strategy for improving the quality and clinical and public health impact of clinical psychology is through a new accreditation system that demands high-quality science training as a central feature of doctoral training in clinical psychology. Just as strengthening training standards in medicine markedly enhanced the quality of health care, improved training standards in clinical psychology will enhance health and mental health care. Such a system will (a) allow the public and employers to identify scientifically trained psychologists; (b) stigmatize ascientific training programs and practitioners; (c) produce aspirational effects, thereby enhancing training quality generally; and (d) help accredited programs improve their training in the application and generation of science. These effects should enhance the generation, application, and dissemination of experimentally supported interventions, thereby improving clinical and public health. Experimentally based treatments not only are highly effective but also are cost-effective relative to other interventions; therefore, they could help control spiraling health care costs. The new Psychological Clinical Science Accreditation System (PCSAS) is intended to accredit clinical psychology training programs that offer high-quality science-centered education and training, producing graduates who are successful in generating and applying scientific knowledge. Psychologists, universities, and other stakeholders should vigorously support this new accreditation system as the surest route to a scientifically principled clinical psychology that can powerfully benefit clinical and public health.

Percutaneous and surgical treatment of pyogenic liver abscesses: observation over a 21-year period in 148 patients

BACKGROUND

Percutaneous drainage of pyogenic liver abscess has become first-line treatment. In the past surgical drainage was preferred in some centres.

AIM

The aim of this retrospective study was to assess the effectiveness of percutaneous treatments and surgical drainage, in terms of treatment success, hospital stay and costs.

PATIENTS

Data of 148 patients (90 males; 58 females; mean age, 61 yrs; range, 30-86 yrs) were retrospectively analysed.

METHODS

Patients' outcomes, including the length of hospital stay, procedure-related complications, treatment failure and death, were recorded. Multiple logistic regression model was used for statistical analysis.

RESULTS

One hundred and four patients (83 with solitary and 21 with multiple abscesses) were treated percutaneously, either by needle aspiration (91 patients) or catheter drainage (13 patients) depending on the abscess's size, and 44 patients (30 with solitary and 14 with multiple abscesses) were treated surgically. There was no statistically significant difference in patients' demographics or abscess characteristics between groups. Hospital stay was longer, and costs were higher in patients treated surgically (p<0.001). There was statistically significant difference in morbidity rate between groups (p<0.001). No death occurred in both groups.

CONCLUSIONS

Percutaneous and surgical treatment of pyogenic liver abscesses are both effective, nevertheless percutaneous drainage carries lower morbidity and is cheaper.

Impact of chronic liver disease and cirrhosis on health utilities using SF-6D and the health utility index

Assessment of health-related quality of life (HRQL) and health utilities have become important aspects of clinical research. Patient-derived utility adjustments are frequently used in economic analysis. Although HRQL has been frequently studied among patients with liver disease, extensive data on the health utilities of patients with liver disease are not available. Recently, SF-6D has been developed to obtain utility scores from the widely used Short Form 36 questionnaire. To assess health utilities of patients with chronic liver disease using 2 utility assessments [SF-6D and Health Utility Index 2 (HUI-2)], a total of 140 patients were identified from our Liver Disease Quality of Life Database with HRQL data available, as well as clinical and demographic data. Of the 140 patients, 42% were female, had a mean age of 49.4 years (standard deviation = +/-11.2) 36% had hepatitis B virus (HBV), 29% had hepatitis C (HCV), 24% had cholestatic liver disease, and 11% had another liver disease (for example, nonalcoholic steatohepatitis). Bivariate analyses indicated that HBV patients had the highest health status as measured by all of SF-6D and HUI-2 subscales and the overall SF-6D and HUI-2 utility measures, whereas patients with HCV and cholestatic liver disease had similar scores, and those with other liver diseases had the poorest quality of life. When controlling for the effects of gender, age, and cirrhosis, impact of chronic liver disease diagnosis on utility scores persisted only for the SF-6D, with HCV patients having significantly poorer health than HBV patients. In conclusion, SF-6D provides not only a generic assessment of HRQL but also a utility score that can be used for economic analysis of patients with chronic liver disease.

Lessons from trial-based cost-effectiveness analyses of mental health interventions: why uncertainty about the outcome, estimate and willingness to pay matters

The principal aim of this article is to share lessons learned by the authors while conducting economic evaluations, using clinical trial data, of mental health interventions. These lessons are quite general and have clear relevance for pharmacoeconomic studies. In addition, we explore how net benefit regression can be used to enhance consideration of key issues when conducting an economic evaluation based on clinical trial data. The first study we discuss found that cost-effectiveness results varied markedly based on the choice of both the patient outcome and the willingness to pay for more of that outcome. The importance of willingness to pay was also highlighted in the results from the second study. Even with a set willingness-to-pay value, most of the time the probability that the new treatment was cost effective was not 100%. In the third study, the cost effectiveness of the new treatment varied by patient characteristics. These observations have important implications for pharmacoeconomic studies. Namely, analysts must carefully consider choice of patient outcome, willingness to pay, patient heterogeneity and the statistical uncertainty inherent in the data. Net benefit regression is a useful technique for exploring these crucial issues when undertaking an economic evaluation using patient-level data on both costs and effects.