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.     

Mapping from Disease-Specific Measures to Utility: An Analysis of the Relationships between the Inflammatory Bowel Disease Questionnaire and Crohn''s Disease Activity Index in Crohn''s Disease and Measures of Utility

OBJECTIVES: To examine the relationship between the Inflammatory Bowel Disease Questionnaire (IBDQ), Crohn's Disease Activity Index (CDAI) and measures of utility (EQ-5D and the SF-6D indexes), and to estimate algorithms to map the two utility values from IBDQ and CDAI scores. METHODS: A large data set from clinical trials in Crohn's disease provided contemporaneous patient responses to all four questionnaires. Paired observations from multiple time-points were analyzed. We calculated mean utility scores by IBDQ and CDAI score deciles; Spearman correlation coefficients for paired observations between IBDQ and EQ-5D (n = 3320) and IBDQ and SF-6D (n = 3230), and explored regression models using maximum likelihood estimation. The IBDQ/SF-6D model was validated against paired observations from an independent data set. RESULTS: The IBDQ decile analysis demonstrated a consistent positive relationship with both utility indexes. Correlations between the IBDQ and both the EQ-5D and SF-6D were statistically significant (P < 0.0001), with correlation coefficients of 0.76 and 0.85, respectively. A simple linear model between EQ-5D and IBDQ explained 45% of the variance. The residuals plot for the IBDQ/SF-6D model suggested some nonlinearity and a nonlinear model explained 69% of the variance. In the validation analysis, no statistically significant difference was observed between the mean observed SF-6D and the SF-6D scores estimated using the IBDQ/SF-6D regression model. CONCLUSIONS: Given the strength, consistency, and predictable characteristics of the relationships, the algorithms appear to provide valuable and valid methods to estimate utilities from IBDQ scores (but not CDAI) in trials of Crohn's disease patients that have collected IBDQ scores but not utilities.     

EQ-5D in a general population survey – A description of the most commonly reported EQ-5D health states using the SF-36

The importance of studying health-related quality of life in the general population has increasingly been emphasized. From a public health perspective, this benefits the identification of population inequalities in health status. One of the currently most popular instruments is the EQ-5D. Evaluations of the EQ-5D generally focus on the overall preference-based index. As this index has a built-in value, exploration of the information from the underlying health states is also important. In this study, the ten most commonly reported EQ-5D health states are described using the SF-36. Data collected in 1999 by questionnaires mailed to a random sample aged 20-74 in south-eastern Sweden were used (n = 9489). Almost 43% reported the best possible EQ-5D health state and 78% were accounted for by three EQ-5D health states. The EQ-5D health state classification was largely reflected by the SF-36, with the EQ-5D items mobility, usual activities, pain/discomfort and anxiety/depression tapping most clearly on the SF-36 scales physical functioning, role limitations due to physical health problems, bodily pain, and mental health, respectively. However, within the same level of EQ-5D (i.e., moderate problems) there was a rather large variation of SF-36 scale scores, particularly regarding the EQ-5D item pain/discomfort and the SF-36 scale BP.     

Do personal and societal preferences differ by socio‐demographic group?

For equity, preferences used in cost-effectiveness analyses (CEAs) should yield similar values for different groups with similar health states. We used data from the US 2000 Medical Expenditure Panel Survey, including socio-demographics, EQ-5D Index and EQ Visual Analog Scale (EQ VAS) scores, to examine whether EQ-5D Index (representing community preferences) and EQ VAS (representing personal preferences) scores differed systematically by socio-demographic group. Differences between EQ-5D Index and EQ VAS scores by socio-demographic group were small and mostly not statistically significant. These preliminary findings suggest that using the EQ-5D Index in CEAs may not contribute to socio-demographic inequities.     

Mapping the EQ-5D index from the SF-12: US general population preferences in a nationally representative sample.

BACKGROUND: Previous mapping algorithms estimating EQ-5D index scores from the SF-12 were based on preferences from a UK community sample. However, preferences based on the general US population are most appropriate for costeffectiveness analyses done from the societal perspective in the United States. OBJECTIVE: To provide a mapping algorithm for estimating EQ-5D index scores from the SF-12 based on a nationally representative sample and using preferences based on the general US population: METHODS: The Medical Expenditure Panel Survey (MEPS) 2002 and 2000 data were used as independent derivation and validation sets to estimate the relationship between SF-12 scores and EQ-5D index scores, controlling for sociodemographic characteristics and comorbidity burden. Prediction equations for end-users who only have access to SF-12 scores were derived and compared. The empirical performance of censored least absolute deviations (CLAD), Tobit, and ordinary least squares (OLS) analytic methods were compared by calculating the mean prediction error in the validation set. RESULTS: The fully specified CLAD model resulted in the lowest mean prediction error, followed by OLS and Tobit. The CLAD prediction equation based only on SF-12 scores performed better than the fully specified OLS and Tobit models. CONCLUSION: The current research provides an algorithm for mapping EQ-5D index scores from the SF-12. This algorithm may provide analysts with an avenue to obtain appropriate preference-based health-related quality-of-life scores for use in cost-effectiveness analyses when only SF-12 data are available.     

Mapping between the Roland Morris Questionnaire and Generic Preference-Based Measures

ObjectivesThe Roland Morris Questionnaire (RMQ) is a widely used health status measure for low back pain (LBP). It is not preference-based, and there are currently no established algorithms for mapping between the RMQ and preference-based health-related quality-of-life measures. Using data from randomized controlled trials of treatment for LBP, we sought to develop algorithms for mapping between RMQ scores and health utilities derived using either the EuroQol five-dimensional questionnaire (EQ-5D) or the six-dimensional health state short form (derived from Medical Outcomes Study 36-Item Short-Form Health Survey) (SF-6D).MethodsThis study is based on data from the Back Skills Training Trial in which data were collected from 701 patients at baseline and subsequently at 3, 6, and 12 months postrandomization using a range of outcome measures, including the RMQ, the EQ-5D, and the Short Form 12 item Health Survey (SF-12) (from which SF-6D utilities can be derived). We used baseline trial data to estimate models using both direct and response mapping approaches to predict EQ-5D and SF-6D health utilities and dimension responses. A multistage model selection process was used to assess the predictive accuracy of the models. We then explored different techniques and mapping models that made use of repeated follow-up observations in the data. The estimated mapping algorithms were validated using external data from the UK Back Pain Exercise and Manipulation trial.ResultsA number of models were developed that accurately predict health utilities in this context. The best performing model for RMQ to EQ-5D mapping was a beta regression with Bayesian quasi-likelihood estimation that included 24 dummy variables for RMQ responses, age, and sex as covariates (mean squared error 0.0380) based on repeated data. The model selected for RMQ to SF-6D mapping was a finite mixture model that included the overall RMQ score, age, sex, RMQ score squared, age squared, and an interaction term for age and RMQ score as covariates (mean squared error 0.0114) based on repeated data.ConclusionsIt is possible to reasonably predict EQ-5D and SF-6D health utilities from RMQ scores and responses using regression methods. Our regression equations provide an empirical basis for estimating health utilities when EQ-5D or SF-6D data are not available. They can be used to inform future economic evaluations of interventions targeting LBP.     

Correlations between disease-specific and generic health status questionnaires in patients with advanced COPD: a one-year observational study

ABSTRACT: BACKGROUND: Longitudinal studies analyzing the correlations between disease-specific and generic questionnaires at different time points in patients with advanced COPD are lacking. The aim of this study was to determine whether and to what extent a disease-specific health status questionnaire (Saint George's Respiratory Questionnaire, SGRQ) correlates with generic health status questionnaires (EuroQol-5-Dimensions, EQ-5D; Assessment of Quality of Life instrument, AQoL; Medical Outcomes Study 36-Item Short-Form Health Survey, SF-36) at four different time points in patients with advanced COPD; and to determine the correlation between the changes in these questionnaires during one-year follow-up. METHODS: Demographic and clinical characteristics were assessed in 105 outpatients with advanced COPD at baseline. Disease-specific health status (SGRQ) and generic health status (EQ-5D, AQoL, SF-36) were assessed at baseline, four, eight, and 12 months. Correlations were determined between SGRQ and EQ-5D, AQoL, and SF-36 scores and changes in these scores. Agreement in direction of change was assessed. RESULTS: Eighty-four patients (80%) completed one-year follow-up and were included for analysis. SGRQ total score and EQ-5D index score, AQoL total score and SF-36 Physical Component Summary measure (SF-36 PCS) score were moderately to strongly correlated. The correlation of the changes between the SGRQ total score and EQ-5D index score, AQoL total score, SF-36 PCS, and SF-36 Mental Component Summary measure (SF-36 MCS) score were weak or absent. The direction of changes in SGRQ total scores agreed slightly with the direction of changes in EQ-5D index score, AQoL total score, and SF-36 PCS score. CONCLUSIONS: At four, eight and 12 months after baseline, SGRQ total scores and EQ-5D index scores, AQoL total scores and SF-36 PCS scores were moderately to strongly correlated, while SGRQ total scores were weakly correlated with SF-36 MCS scores. The correlations between changes over time were weak or even absent. Disease-specific health status questionnaires and generic health status questionnaires should be used together to gain complete insight in health status and changes in health status over time in patients with advanced COPD.     

The validity of generic and condition-specific preference-based instruments: the ability to discriminate asthma control status

Objective A goal of asthma management is to improve the patient’s health-related quality of life (HRQL). However, it is unclear whether HRQL instruments can discriminate across asthma control measures. The objective of this study was to evaluate the validity of generic and condition-specific preference-based instruments, in terms of their ability to distinguish asthma control. Methods Asthma patients (n = 157) completed three generic preference-based instruments: the Health Utility Index Mark 3 (HUI-3), the EuroQol (EQ-5D), and the Short Form 6D (SF-6D) and two condition-specific questionnaires: the standardized Asthma Quality of Life Questionnaire (AQLQ(S)) and the Asthma Control Questionnaire (ACQ). The AQLQ(S) scores were converted into the condition-specific preference-based scores: the Asthma Quality of Life Utility Index (AQL-5D). Results The preference-based instruments were generally able to discriminate across control measures, such as ACQ scores and magnitude of asthma medication, but were not able to discriminate for self-reported control and severity levels. These instruments also correlated with most control measures (r = 0.32–0.37). Significant relationships between AQL-5D scores and all control variables were observed. Conclusions Overall, the AQL-5D discriminated across all levels of asthma control. The HUI-3, the EQ-5D, and the SF-6D differentiated between the highest and lowest levels of control but could not discriminate between the moderate levels.     

Probabilistic mapping of the health status measure SF-12 onto the health utility measure EQ-5D using the US-population-based scoring models

Purpose

Probabilistic mapping of the health status instrument SF-12 onto the health utility instrument EuroQol—5 dimensions (EQ-5D)-3L using the UK-population-based scoring model showed encouraging results as compared to other mapping methods, although its predictive performance using the US-population-based EQ-5D scoring models has not been investigated. In addition, a new and improved US-population-based EQ-5D scoring method has recently been developed and suggested for use in applications that required US societal health state values. In this study, we assessed predictive performance of the probabilistic mapping approach using the US-population-based scoring models on EQ-5D utility scores based on SF-12 responses and compared the results with those of other mapping methods.

Methods

Using a sample of 19,678 adults from the 2003 Medical Expenditure Panel Survey, we evaluated the predictive performance of probabilistic mapping using Bayesian networks, response mapping using multinomial logistic regression, ordinary least squares, and censored least absolute deviations models by implementing a fivefold cross-validation method. The EQ-5D utility scores were generated using two US-population-based models: D1 and MM-OC.

Results

Overall, the probabilistic mapping approach using Bayesian networks consistently outperformed other mapping methods with mean squared errors (MSE) of 0.007 and 0.007, mean absolute errors (MAE) of 0.057 and 0.039, and overall R ² of 0.773 and 0.770 for the US-population-based EQ-5D scoring D1 and MM-OC models, respectively.

Conclusion

The probabilistic mapping approach can be useful to estimate EQ-5D utility scores from SF-12 responses with better predictive measures in terms of MSE, MAE, and R ² than other common mapping methods.     

Using the Multiple Sclerosis Impact Scale to Estimate Health State Utility Values: Mapping from the MSIS-29, Version 2, to the EQ-5D and the SF-6D

ObjectivesThe 29-item Multiple Sclerosis Impact Scale (MSIS-29) is a psychometrically validated patient-reported outcome measure increasingly used in trials of treatments for multiple sclerosis. However, it is non–preference-based and not amenable for use across policy decision-making contexts. Our objective was to statistically map from the MSIS-29, version 2, to the EuroQol five-dimension (EQ-5D) and the six-dimension health state short form (derived from short form 36 health survey) (SF-6D) to estimate algorithms for use in cost-effectiveness analyses.MethodsThe relationships between MSIS-29, version 2, and EQ-5D and SF-6D scores were estimated by using data from a cohort of people with multiple sclerosis in South West England (n=672). Six ordinary least squares (OLS), Tobit, and censored least adjusted deviation (CLAD) regression analyses were conducted on estimation samples, including the use of subscale and item scores, squared and interaction terms, and demographics. Algorithms from models with the smallest estimation errors (mean absolute error [MAE], root mean square error [RMSE], normalized RMSE) were then assessed by using separate validation samples.ResultsTobit and CLAD. For the EQ-5D, the OLS models including subscale squared terms, and item scores and demographics performed comparably (MAE 0.147, RMSE 0.202 and MAE 0.147, RMSE 0.203, respectively), and estimated scores well up to 3 years post-baseline. Estimation errors for the SF-6D were smaller (OLS model including squared terms: MAE 0.058, RMSE 0.073; OLS model using item scores and demographics: MAE 0.059, RMSE 0.08), and the errors for poorer health states found with the EQ-5D were less pronounced.ConclusionsWe have provided algorithms for the estimation of health state utility values, both the EQ-5D and SF-6D, from scores on the MSIS-29, version 2. Further research is now needed to determine how these algorithms perform in practical decision-making contexts, when compared with observed EQ-5D and SF-6D values.     

Quality of life of people with venous leg ulcers: A comparison of the discriminative and responsive characteristics of two generic and a disease specific instruments

Background: Venous leg ulcers are an important source of morbidity in society. Measuring the impact of leg ulcers on quality of life is important within clinical and economic evaluations. In this study we report a validation study of the leg ulcer disease specific Hyland questionnaire and compare its discriminative and responsive characteristics to general health quality of life measures: the SF-12 and EQ-5D. Methods: HRQoL of venous leg ulcer patients from 9 UK regions was measured using SF-12, EQ-5D and Hyland, at baseline and every three months for 1 year. Psychometric analysis was used to confirm the validity of the Hyland questionnaire. Quarterly scores for all instruments were calculated. Effect size and standardised mean difference were used to investigate the responsiveness to ulcer healing and discriminative abilities of the instruments. Results: Three hundred and eighty seven individuals were recruited into the VenUS I study. Baseline health related quality of life data from the study participants suggested a two factor solution for the Hyland. This questionnaire was associated with small and moderate ability to discriminate individuals according to age, mobility, initial ulcer size and ulcer duration. SF-12 and EQ-5D had good evaluative properties; both instruments were responsive to changes in HRQoL after ulcer healing. High levels of bodily pain were reported in the SF-12 questionnaire, whilst only minor ulcer related discomfort was reported in the Hyland. Discussion: SF-12 and EQ-5D are suitable for exploring dimensions of health related quality of life in people with chronic venous leg ulceration. The responsiveness to healing of the Hyland questionnaire is unclear. We would recommend the use of generic instruments for the measurement of HRQoL in patients with venous leg ulcers.     

An evaluation of patient-reported outcome measures in lower limb reconstruction surgery

Purpose

To assess the measurement properties (acceptability, validity, reliability and responsiveness), of the MOS 36-Item Short-Form Health Survey (SF-36), the EQ-5D, the Short-Form McGill Pain Questionnaire (SF-MPQ) and the Musculoskeletal Functional Assessment Instrument (MFA), in patients who have undergone limb reconstruction surgery (LRS).

Methods

Four instruments measuring patient-reported outcome were completed at baseline and 12?months from surgery.

Results

101 LRS patients were recruited with 95 responding at baseline and 71 at a 12-month follow-up. Response rates at baseline were over 94%. In three instruments, there was evidence of floor or ceiling effect, the exception being the EQ-5D. Cronbach??s ?? statistics of internal consistency reliability were acceptable at ??0.80 for all dimensions of the MFA, the SF-MPQ PRI(S) and seven of the SF-36 dimensions. When comparing mean changes in scores between baseline and 12?months, the most responsive measure was the SF-36 with an average Standardised Response Mean of 0.48 for those who reported their health as better. Statistically significant differences were observed between the health change groups (??worse??, ??better?? and ??same??) for four dimensions of the SF-36, the two summary scores and the SF-6D.

Conclusions

Variation and poor performance of some of the instruments resulted in a recommendation of using the SF-36 and the SF-6D for LRS patients.     

Quality-Adjusted Life Expectancies in Patients with Rheumatoid Arthritis—Comparison of Index Scores from EQ-5D, 15D,and SF-6D

BackgroundThe aim of this study was to compare quality-adjusted life expectancy (QALE) for patients with rheumatoid arthritis generated from three generic health-related quality-of-life instruments.MethodsPatients from 11 Danish rheumatology outpatient clinics were asked to report current health status using the EuroQol five-dimensional questionnaire (EQ-5D), 15D, and six-dimensional health state short form (derived from SF-12) (SF-6D) instruments. Clinical staff provided data on current disease status (C-reactive protein and Disease Activity Score that involves clinical assessment of 28 joints). National mortality data were retrieved from Statistics Denmark. For each of the three instruments, mean index scores were estimated by gender and 5-year age groups. Partial QALE was estimated for the age interval 30 to 79 years for different subsamples.ResultsAlthough the three quality-of-life index scores were highly correlated, there were statistically significant differences between the average index scores from the three instruments. The 15D provided the highest index score and SF-6D the lowest score. For a 30-year-old patient, the partial QALE ranged from 37.9 quality-adjusted life-years using the SF-6D to 45.6 quality-adjusted life-years using the 15D. The QALE for men and women differed by 6.2%, 4.0%, and 5.3% when the calculation was based on EQ-5D, SF-6D, and 15D index scores, respectively. The largest differences were observed when patients were grouped by functional status (Health Assessment Questionnaire score), where the EQ-5D showed a 50% difference in index score between the best and worst functional group while the SF-6D and 15D showed smaller differences (32% and 14%, respectively).DiscussionThis analysis has shown the difference in QALE estimates related to different instruments. The study emphasizes that unless outcome studies use the same instruments and scoring algorithms, the results will not be directly comparable.     

Comparing utility scores before and after hearing-aid provision

Utility scores were estimated for 609 hearing-impaired adults who completed EQ-5D, Health Utilities Index Mark III (HUI3) and SF-6D survey instruments both before and after being provided with a hearing aid. Pre-intervention, the mean utility scores for EQ-5D (0.80) and SF-6D (0.78) were significantly higher than the mean HUI3 utility score (0.58). Post-intervention, the mean improvement in the HUI3 (0.06 change) was significantly higher than the mean improvement according to the EQ-5D (0.01 change) or SF-6D (0.01 change). The estimated cost effectiveness of hearing-aid provision is therefore likely to be dependent on which instrument is used to measure utility.     

An empirical comparison of EQ-5D and SF-6D in liver transplant patients

There remains disagreement about the preferred utility-based measure of health-related quality of life for use in constructing quality-adjusted life years (QALYs). The recent development of a new measure, the SF-6D, has highlighted this issue. The SF-6D and EuroQol EQ-5D measure health-related utilities on a scale where 0 represents death and 1 represents full health, and both have utility scores generated from random samples of the general UK population. This study explored whether, in a large sample of liver transplant patients, the two instruments provide similar results. The empirical data highlight important variation in the results generated from the use of the two instruments. The data are consistent with a view that the SF-6D does not describe health states at the lower end of the utility scale but is more sensitive than EQ-5D in detecting small changes towards the top of the scale.     

Validity of the Thai EQ-5D in an occupational population in Thailand

Purpose

To assess the construct validity of the Thai EuroQoL (EQ-5D) among an occupational population in Thailand.

Methods

Data were derived from a large cohort study among employees of the Electricity Generating Authority of Thailand. In 2008 and 2009, 4,850 participants completed the Thai EQ-5D and Short-Form 36 version 2 (SF-36v2). Thai preferences weights were used to convert EQ-5D health states into EQ-5D index scores. Construct validity of the Thai EQ-5D was examined by specifying and testing hypotheses about the relationships between the EQ-5D, SF-36v2, and participants’ demographic and medical characteristics.

Results

Construct validity of the Thai EQ-5D was supported by expected relationships with SF-36v2 scale and summary scores. For example, SF-36v2 scores on the mental health scale were much lower for participants who reported having problems on the EQ-5D anxiety/depression dimension compared to those reporting no problems (mean norm-based SF-36v2 scores: 52.9 vs. 41.8, p < 0.001). Additionally, reporting a problem in a given EQ-5D dimension was generally associated with lower SF-36v2 summary scores. The EQ-5D index score distinguished between groups of participants in the expected manner, on the basis of sex, age, education and self-reported health, thus providing evidence of known-groups validity.

Conclusion

The study demonstrated good construct validity of the Thai EQ-5D in a large occupational population in Thailand.