Mapping the SF-12 to the EuroQol EQ-5D Index in a national US sample.

BACKGROUND: Preference scores for the Medical Outcomes Study (MOS) SF-12 would enable its use in cost-effectiveness analyses. Previous mapping studies of MOS instruments top reference-based instruments have not examined performance in national samples. PARTICIPANTS: 15,000 adults in the 2000 Medical Expenditure Panel Survey annual survey including the SF-12 and EQ-5D Index. METHODS: Regression of the EQ-5D Index scores onto the physical and mental component summary scores of the SF-12, testing 2nd-4th degree polynomial and spline models, including and excluding sociodemographics. RESULTS: A 2nd degree polynomial model explained 63% of the variance in EQ-5D scores, with robust internal and external validation. More complex mod-els explained minimally additional variance. Compared with EQ-5D valuations, prediction models overestimated the lowest health states (6% of the population). CONCLUSIONS: The mapped SF-12 yields usable preference-scaled scores, with some caution for the lowest health states.     

Comparison of the Health Utilities Index Mark 3 (HUI3) and the EuroQol EQ-5D in patients treated for intermittent claudication

The Health Utilities Index Mark 3 (HUI3) and the EuroQol EQ-5D (EQ-5D) were compared to each other and to other quality-of-life (QoL) measures in patients treated for intermittent claudication. A total of 88 patients with intermittent claudication completed the HUI3, EQ-5D, RAND 36-Item Health Survey 1.0, time tradeoff, standard gamble, and rating scale before revascularization and at follow-up at 1 month, 3 months, and 1 year. The effect of treatment on the HUI3 and EQ-5D dimensions and the overall scores, calculated using published formulas based on societal preferences, were compared. After 1 month of treatment, the majority of patients showed improvement on the HUI3 dimensions ambulation and pain and on the EQ-5D dimensions mobility, usual activities, and pain/discomfort. The mean HUI3 score was significantly higher than the mean EQ-5D score (0.66 and 0.57, respectively, p < 0.01) before treatment. After treatment, however, they were not significantly different from each other (e.g., 12 months after treatment: 0.77 and 0.75, respectively (p > 0.05). After 1 month, the scores did not change significantly over time (p > 0.05). The intraclass correlation coefficient between changes over time in the HUI3 and EQ-5D scores was 0.30, with other health-related quality-of-life (HRQoL) measures the correlations for HUI3 and EQ-5D were very similar. In conclusion, both the HUI3 and EQ-5D demonstrated an effect of treatment in patients with intermittent claudication; in addition, they showed similar relationships with other (HRQoL) measures. To demonstrate the effect of revascularization in patients with intermittent claudication, however, clinicians and researchers should be aware of the differences in the mean HUI3 and EQ-5D scores. This revised version was published online in June 2006 with corrections to the Cover Date.     

Predicting EuroQoL EQ-5D preference scores from the SF-12 Health Survey in a nationally representative sample.

PURPOSE: To predict the EuroQoL EQ-5D utility index from the SF-12 Health Survey for a US national sample of adults. METHODS: The authors used the 2000 Medical Expenditure Panel Survey to examine the relationship between instruments. Linear regression was used to predict EQ-5D scores from Physical Component Summary (PCS) and Mental Component Summary (MCS) scores of the SF-12. A prediction model was derived in one half of the sample and validated in the other half. RESULTS: Complete responses to both measures were available for 14,580 adults; 7313 (50.2%) surveys were used for the derivation set. The 2-variable model predicted 61% of the variance in EQ-5D scores and provided reasonable ability to predict mean EQ-5D scores from mean PCS and MCS scores. Confidence intervals are dependent on sample size and variance of PCS and MCS scores. CONCLUSIONS: EQ-5D scores can be reasonably predicted from the SF-12. This model allows researchers to estimate utility data for use in decision and cost-utility analyses.     

Testing the measurement equivalence of paper and touch-screen versions of the EQ-5D visual analog scale (EQ VAS)

OBJECTIVES: This study examined the measurement equivalence of the original paper-based vertical format of the EQ-5D visual analog scale (EQ VAS) with a touch-screen computer-based horizontal format. METHODS: A total of 314 subjects were administered two modes of the EQ VAS in a randomized crossover design. One mode was the original paper-based 20 cm vertical EQ VAS; the other mode was touch-screen-based. Measurement equivalence was assessed by testing the 95% confidence interval of the mean differences from an equivalence threshold of -3 to +3 points on the VAS and evaluating the intraclass correlation coefficient (ICC). RESULTS: The adjusted mean (SE) EQ VAS score was 80.96 (0.87) on the paper and 79.59 (0.85) on the touch-screen. The mean (CI) difference between scores on the two formats was 1.37 with a confidence interval of 0.175-2.559, wholly contained within the equivalence interval. The ICC was 0.75, indicating acceptable agreement between the two modes. Almost a third (30.1%) of the respondents reported identical scores on both formats. CONCLUSION: These results provide evidence for the measurement equivalence of this EQ VAS touch-screen administration mode with the original paper mode.     

Changes in quality of life in chronic psychiatric patients: A comparison between EuroQol (EQ-5D) and WHOQoL

It has often been postulated that simple, short questionnaires are unable to reflect complex changes in well-being of individuals with chronic psychiatric disorders. To investigate these assumptions we included two recently developed instruments to measure quality of life (the WHOQoL-Bref and the EuroQoL EQ-5D) in a randomised control trial (RCT) in which two treatment conditions were compared. Aims of the study were to assess the sensitivity and validity of these quality of life (QoL)-instruments, to establish their relationship and to examine the predictors of changes in QoL. Subjective changes in QoL were measured on three assessments waves in a period of 18 months and compared to objective changes in psychopathology and social functioning in a sample of 76 chronic schizophrenic patients who participated in the RCT. Results indicated that both WHOQoL-Bref and EuroQoL EQ-5D are capable of detecting changes in QoL over time in physical and psychological well-being. The instruments partly measure the same aspects of QoL, indicated by 50% common variance on total scores. Reduction of positive psychotic symptoms appeared to be the most important factor in improving QoL. The weighted TTO-score of EuroQoL-5D, which is often used as an index in economic evaluations of health care, did however not correspond with these changes, which indicates that it is less sensitive to changes in social and psychological well-being. Its use as the core measure in (economic) health evaluation in the field of psychiatry therefore seems less appropriate.     

The association of survey language (Spanish vs. English) with Health Utilities Index and EQ-5D index scores in a United States population sample

Objective  

To explore whether variations in the EQ-5D, Health Utilities Index (HUI) Mark II (HUI2), and HUI Mark III (HUI3) index scores were associated with the survey language (Spanish vs. English) in the US Valuation of the EQ-5D Health States study.     

Modelling the EuroQol data: a comparison of discrete choice conjoint and conditional preference modelling.

This article compares two measurement strategies for measuring EuroQol health state preferences: (a) conditional preference modelling, implemented using rating scale and standard gamble scaling methods and (b) discrete choice conjoint modelling. The nature of the model form of the EuroQol health status preference function and the predictive ability of each measurement strategy formed the basis of the comparison. Data were collected via personal interviews with 140 US patients, 139 of whom provided usable responses. Both strategies supported a multiplicative model form as representative of the EuroQol health status preference function and were acceptable in terms of predictive ability. The agreement of the two measurement strategies on the nature of the model form provides evidence of the convergent validity of the multiplicative nature of the EuroQol health status preference function in this patient population. Since both strategies were found to be acceptable in terms of predictive ability, further research comparing preference scores and measuring respondent evaluations of the methodologies is necessary to illustrate the relative strengths and weaknesses of different health state preference measurement methodologies.     

Measuring health-related quality of life in bipolar disorder: Relationship of the EuroQol (EQ-5D) to condition-specific measures

Generic utility measures of health-related quality of life provide an independent net valuation of health states. They are increasingly used with condition-specific outcome measures in assessing treatments. In Bipolar Disorder, a few studies indicate poorer quality of life for depressed vs. euthymic patients. A single study suggests mania is less negative than depression. This analysis examines the relationship of one such scale, the EuroQol (EQ-5D), to objective and subjective measures of depression and mania in 221 Bipolar subjects, recently or still in an episode of illness. Results: Depressed patients showed a very poor quality of life (median EQ-5D Index score 0.41). Index and Visual Analogue scores improved significantly as level of depression decreased (Jonckheere–Terpstra test p<0.001). Both scores were significantly negatively related to all depression measures. Patients reported problems across all areas of life covered by the EQ-5D. No such relationships were observed between EQ-5D scores and mania measures, though all mania measures were inter-related. However, the range of mania shown was quite restricted. Conclusions: The EQ-5D is a useful measure of quality of life for Bipolar patients suffering from depression. Conclusions about the role of the EQ-5D in mania are restricted by the limited range of mania observed.     

A view from the bridge: agreement between the SF-6D utility algorithm and the Health Utilities Index

BACKGROUND: The SF-6D is a new health state classification and utility scoring system based on 6 dimensions ('6D') of the Short Form 36, and permits a "bridging" transformation between SF-36 responses and utilities. The Health Utilities Index, mark 3 (HUI3) is a valid and reliable multi-attribute health utility scale that is widely used. We assessed within-subject agreement between SF-6D utilities and those from HUI3. METHODS: Patients at increased risk of sudden cardiac death and participating in a randomized trial of implantable defibrillator therapy completed both instruments at baseline. Score distributions were inspected by scatterplot and histogram and mean score differences compared by paired t-test. Pearson correlation was computed between instrument scores and also between dimension scores within instruments. Between-instrument agreement was by intra-class correlation coefficient (ICC). RESULTS: SF-6D and HUI3 forms were available from 246 patients. Mean scores for HUI3 and SF-6D were 0.61 (95% CI 0.60-0.63) and 0.58 (95% CI 0.54-0.62) respectively; a difference of 0.03 (p<0.03). Score intervals for HUI3 and SF-6D were (-0.21 to 1.0) and (0.30-0.95). Correlation between the instrument scores was 0.58 (95% CI 0.48-0.68) and agreement by ICC was 0.42 (95% CI 0.31-0.52). Correlations between dimensions of SF-6D were higher than for HUI3. CONCLUSIONS: Our study casts doubt on the whether utilities and QALYs estimated via SF-6D are comparable with those from HUI3. Utility differences may be due to differences in underlying concepts of health being measured, or different measurement approaches, or both. No gold standard exists for utility measurement and the SF-6D is a valuable addition that permits SF-36 data to be transformed into utilities to estimate QALYs. The challenge is developing a better understanding as to why these classification-based utility instruments differ so markedly in their distributions and point estimates of derived utilities.     

A comparison of EQ-5D index scores derived from the US and UK population-based scoring functions.

The authors recently introduced a new preference-based scoring function for the EQ-5D (D1 model) based on time tradeoff valuations from the general adult US population: In this study, they compared the EQ-5D index scores derived from the US (D1) algorithm to the more familiar UK (N3) algorithm. They compared preference-based EQ-5D index scores for all possible EQ-5D health states and differences in EQ-5D index scores between pairs of EQ-5D health states predicted by the D1 and N3 models. The responsiveness of D1- and N3-predicted EQ-5D index scores was assessed using simulated transitions between EQ-5D health states. The mean (SD) EQ-5D index scores for all 243 health states predicted by the D1 and N3 models were 0.37 (0.23) and 0.14 (0.31), respectively. The mean (SD) absolute difference in EQ-5D index scores for all 29,403 pairs of health states was 0.25 (0.19) and 0.35 (0.27), according to the D1 and N3 models, respectively. The D1 and N3 models were consistent in predicting gains/losses for 27,592 (94%) transitions between EQ-5D health state pairs; Cohen effect size, calculated using these 27,592 consistent transitions, was 1.58 and 1.59 for the D1 and N3 models, respectively. Based on these simulation results, it appears that the D1 model would lead to smaller gains in quality-adjusted life years than the N3 model; however, their responsiveness appears to be similar. Empirical studies are needed to examine whether these 2 EQ-5D scoring functions would lead to different conclusions in cost-utility analyses.     

Proxy assessment of quality of life in pediatric clinical trials: Application of the Health Utilities Index 3

Background: With increased cure rates, pediatric oncology protocols increasingly seek to document the impact of treatment on patients disease, symptoms, and functional capacity. Procedure: Nurses as proxy respondents used the Health Utilities Index 3 (HUI3) to assess the health-related quality of life (HRQL) in twenty-five patients (age 6years or older) enrolled on a frontline protocol for leukemia. HRQL observations (n = 70) were made at three different time points to coincide with high-dose methotrexate therapy. Additionally, the proxy respondents evaluated the ease of use of the instrument and the data quality. Results: As patients health status declined, the number of unassessable HRQL items increased. These missing data made scoring cumbersome and precluded calculation of the overall HRQL scores for nearly 50% of the patients. Conclusions: Use of the provider proxy-assessed HUI3 in pediatric cancer trials may result in a high proportion of missing data. Trials may benefit more from the use of HRQL measures that consider the acuity of the childs illness, domains specific and sensitive to both disease and treatment, and items that can be proxy-assessed independent of input from parent or patient. Evaluations that combine child self-reports with both parent and provider reports may ultimately provide the most reliable and comprehensive perspective on childrens quality of life.     

US and UK versions of the EQ-5D preference weights: Does choice of preference weights make a difference?

Background Most US studies that estimate EQ-5D index score generally apply the UK preference weights. We compared the validity of a newly-developed US weights to the UK weights for use of EQ-5D as a measure of health-related quality of life. Methods Data were collected from a randomized clinical trial for patients with HIV (n = 1,126) in the US. Convergent validity was examined by comparing Pearson correlations of EQ-5D index scores with the MOS-HIV Health Survey scale scores and Physical and Mental Health Summary (PHS, MHS) scores using the US and UK weights. Known-groups validity of EQ-5D US versus UK index scores was compared using clinical variables (CD4+ cell count and HIV viral load), and the MOS-HIV PHS and MHS. Score changes in the EQ-5D index from baseline to week 50 were examined using effect size (ES) estimates. Results The mean EQ-5D index scores was slightly higher using US weights than UK weights (0.87 vs. 0.84, respectively). The correlation coefficient for EQ-5D utilities using the US and UK weights was 0.98. The correlations of EQ-5D index scores with the MOS-HIV scores were moderate and similar using the US and UK weights. The EQ-5D index scores discriminated equally well for both versions between levels of CD4+ count, HIV viral load, and PHS and MHS scores (P < 0.05), suggesting equivalent known-groups validity. The changes in EQ-5D index scores from baseline to week 50 were similar for both versions (ES: 0.21 vs. 0.22 for US and UK, respectively), suggesting equivalent responsiveness to score changes. Conclusions EQ-5D index scores generated using UK and US preference weights showed equivalent psychometric properties. For assessing treatment benefit in a single population, the use of either the UK or US weights as a measure of HRQOL will not change inferences. However, for comparisons across US and UK populations, the choice between these two weights should be based on their relevance to the study population.     

How the EQ-5D utilities are derived matters in Chinese diabetes patients: a comparison based on different EQ-5D scoring functions for China

Quality of Life Research - In China, multiple approaches to calculating EQ-5D utilities are available, including the two EQ-5D-3L (3L2014 and 3L2018) scoring functions, the EQ-5D-5L (5L) scoring...     

Mapping from the Health Assessment Questionnaire to the EQ-5D: The Impact of Different Algorithms on Cost-Effectiveness Results

BackgroundMany algorithms exist for converting the Health Assessment Questionnaire (HAQ) score to utility in rheumatoid arthritis (RA). Different algorithms convert the same HAQ score to different utility values, and could therefore lead to different cost-effectiveness results.ObjectiveTo investigate the impact of different mapping algorithms within the same cost-effectiveness model.MethodsWe rebuilt an existing economic model that had previously been used for estimating the cost-effectiveness of second-line biologics in RA. We reviewed the literature to identify algorithms that converted the HAQ score to utility and incorporated them into the model. We compared the cost-effectiveness results using different algorithms, exploring the reasons behind the different results and the potential effect on reimbursement decisions.ResultsWe identified 24 different algorithms that estimated utility on the basis of the HAQ score, age, sex, and pain. The incremental cost-effectiveness ratio for rituximab versus disease-modifying antirheumatic drugs varied between £18,407/quality-adjusted life-year and £32,039/quality-adjusted life-year, which we speculate could have changed the recommendations made by the National Institute for Health and Care Excellence.ConclusionsUsing different algorithms to convert the HAQ score to utility affects the cost-effectiveness of second-line biologics for the treatment of RA. Using different algorithms in economic modeling for RA could lead health technology assessment bodies to make different reimbursement decisions.     

A comparison of EQ-5D index scores using the UK,US, and Japan preference weights in a Thai sample with type 2 diabetes

Background  

Data are scarce on the comparison of EQ-5D index scores using the UK, US, and Japan preference weights in other populations. This study was aimed to examine the differences and agreements between these three weights, psychometric properties including test-retest reliability, convergent and known-groups validity, and the impact of differences in the EQ-5D scores on the outcome of cost-utility analysis in Thai people.