Responsiveness of generic health-related quality of life measures in stroke

Objective: To compare five preference-based generic measures of health-related quality of life (HRQOL) in terms of change scores, correlations among change scores, responsiveness, and quality adjusted life-years (QALYs) gained. Design: Observational longitudinal cohort study where clinical measures and self-assessed HRQOL measures were administered to stroke patients at baseline and at 6 months. Patients were categorized as ‘stable’, ‘some improvement’ and ‘large improvement’ using the Barthel Index, Modified Rankin Scale (MRS), and Center for Epidemiologic Studies Depression Scale (CES-D). For each group, paired t -tests and variants of effect size were used to compare the responsiveness of preference-based HRQOL summary scores, including the EQ-5D VAS and index-based score, SF-6D, and Health Utilities Index (HUI) Mark 2 (HUI2) and Mark 3 (HUI3) overall utility scores. Results: Ninety-eight of 124 (79%) patients completed the 6-month follow-up. Change scores of the EQ-Index, HUI2, and HUI3 were strongly correlated with changes in the Barthel Index and MRS, while the EQ-5D VAS had higher correlation with CES-D change scores than the other measures. The SF-6D, HUI3, and EQ-Index were generally more responsive than the HUI2 and EQ-5D Visual analogue scale (EQ-VAS). QALY estimates based on the EQ-5D index and HUI3 were twice as large as estimates based on the SF-6D and HUI2. Conclusions : The results of this study may assist in informing the selection of a preference-based generic HRQOL measure, although choice will also depend on study goals and context. We would caution against the generalization of the study results on responsiveness to conditions when more subtle change is expected.     

Not all "quality-adjusted life years" are equal

BACKGROUND: There is evidence that utility elicitation methods used in the calculation of quality-adjusted life years (QALYs) yield different results. It is not clear how these differences impact economic evaluations. METHODS: Using a mathematical model incorporating data on efficacy, costs, and utility values, we simulated the experiences of 100,000 hypothetical rheumatoid arthritis patients over 10 years (50,000 exposed to infliximab plus methotrexate [MTX] and 50,000 exposed to MTX alone). QALYs, were derived from the Health Utilities Index 2 and 3 (HUI2 and HUI3), the Short Form 6-D (SF-6D), and the Euroqol 5-D (EQ-5D). Incremental cost-utility ratios were determined using each instrument to calculate QALYs and the results were compared using cost-effectiveness acceptability curves. RESULTS: Using the different utility measurement methods, the mean difference in QALYs between the infliximab plus MTX and MTX groups ranged from a high of 1.95 QALYs (95% CI=1.93-1.97) using the HUI3 to 0.89 QALYs (95% CI=0.88-0.91) using the SF-6D. Adopting the commonly cited value of society's willingness to pay for a QALY of $50,000, 91% of the simulations favored the cost utility of infliximab plus MTX when using the HUI3 to calculate QALYs. However, when using the EQ-5D, HUI2, or the SF-6D utility values to calculate QALYS, the proportion of simulations that favored the cost utility of infliximab were 63%, 45%, and 12%, respectively. CONCLUSION: Depending on the method for determining utility values used in the calculation of QALYs, very different incremental cost-utility ratios are generated.     

A comparison of generic, indirect utility measures (the HUI2, HUI3, SF-6D, and the EQ-5D) and disease-specific instruments (the RAQoL and the HAQ) in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common, chronic disease where health-related quality of life (HRQL) is one of the main goals of therapy. As such, instruments used to measure HRQL in RA must be able to discriminate across RA severity. The two basic categories of instruments used to measure HRQL are generic instruments and disease-specific instruments. Generic instruments can be further subdivided into preference-based measures which yield both single and multi-attribute utility values anchored at zero (death) and 1.00 (perfect health) as a measure of HRQL. The scores from these types of instruments can be integrated into cost-utility analyses as the weightings for quality adjusted life years. We assessed the construct validity of utility scores from four generic preference-based measures (the Health Utilities Index 2 and 3 (HUI2, HUI3), the EuroQol 5D (EQ-5D), and the Short Form 6-D (SF-6D) and disease specific measures (the Rheumatoid Arthritis Quality of Life Questionnaire (RAQoL) and the Health Assessment Questionnaire (HAQ)) in a sample of 313 RA patients in British Columbia, Canada. We also estimated the minimally important differences (MID) for each of the measures. Generally, as anticipated, the disease-specific measures were better able to discriminate across groups with higher RA severity; however, utility scores from each of the scales also appeared to discriminate well across RA severity categories. The MID values agreed with those previously reported in the literature for the HUI2, SF-6D and the HAQ and provided new information for the HUI3, EQ-5D and the RAQoL. We conclude that the all of the preference-based utility measures that were evaluated appear to adequately discriminate across levels of RA severity.     

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.     

Choosing between measures: comparison of EQ-5D,HUI2 and HUI3 in persons with hearing complaints

Objectives To generate insight into the differences between utility measures EuroQol 5D (EQ-5D), Health Utilities Index Mark II (HUI2) and Mark III (HUI3) and their impact on the incremental cost-effectiveness ratio (ICER) for hearing aid fitting Methods Persons with hearing complaints completed EQ-5D, HUI2 and HUI3 at baseline and, when applicable, after hearing aid fitting. Practicality, construct validity, agreement, responsiveness and impact on the ICER were examined. Results All measures had high completion rates. HUI3 was capable of discriminating between clinically distinctive groups. Utility scores (n = 315) for EQ-5D UK and Dutch tariff (0.83; 0.86), HUI2 (0.77) and HUI3 (0.61) were significantly different, agreement was low to moderate. Change after hearing aid fitting (n = 70) for HUI2 (0.07) and HUI3 (0.12) was statistically significant, unlike the EQ-5D UK (0.01) and Dutch (0.00) tariff. ICERs varied from €647,209/QALY for the EQ-5D Dutch tariff to €15,811/QALY for HUI3. Conclusion Utility scores, utility gain and ICERs heavily depend on the measure that is used to elicit them. This study indicates HUI3 as the instrument of first choice when measuring utility in a population with hearing complaints, but emphasizes the importance of a clear notion of what constitutes utility with regard to economic analyses.     

Are indirect utility measures reliable and responsive in rheumatoid arthritis patients?

Background: Preference-based, generic measures are increasingly being used to measure quality of life and as sources for quality weights in the estimation of Quality Adjusted Life Years (QALYs) in rheumatoid arthritis (RA). However, among the most commonly used instruments (the Health Utilities Index 2 and 3 [HUI2 and HUI3], the EuroQoL-5D [EQ-5D], and the Short Form-6D [SF-6D], there has been little comparative research. Therefore, we examined the reliability and responsiveness of these measures and the Rheumatoid Arthritis Quality of Life (RAQoL) and the Health Assessment Questionnaire (HAQ) in a sample of RA patients. Major findings: Test–retest reliability was acceptable for all of the instruments with the exception of the EQ-5D. Using two external criteria to define change (a patient transition question and categories of the patient global assessment of disease activity VAS), the RAQoL was the most responsive of the instruments. For the indirect utility instruments, the HUI3 and the SF-6D were the most responsive for measuring positive change. On average, for patients whose RA improved, the absolute change was highest for the HUI3. Conclusions: The HUI3 and the SF-6D appear to be the most responsive of the preference-based instruments in RA. However, differences in the magnitude of the absolute change scores have important implications for cost-effectiveness analyses.     

Comparing the Health Utilities Index Mark 3 (HUI3) with the Short Form-36 Preference-Based SF-6D in Chronic Kidney Disease

Objective:  Assess within-subject agreement and compare discriminative abilities between the SF-6D and the Health Utilities Index Mark 3 (HUI3) in patients with chronic kidney disease (CKD).
Methods:  The HUI3 and Short Form-36 were self-completed by 185 CKD patients enrolled in a prospective study of incident patients with stage 4 and 5 CKD.
Results:  The mean preference-based score for the SF-6D was 0.67 ± 0.13 compared to 0.58 ± 0.26 for the HUI3 ( P  < 0.01). There was a strong association between SF-6D and HUI3 scores (Pearson correlation coefficient 0.55, 95% CI 0.43–0.65) and moderate agreement with an intraclass correlation coefficient of 0.44. The HUI3 was better able to capture more severe burden of illness with fewer floor effects. The SF-6D was better at capturing differences among patients at the top range of the scale with fewer ceiling effects. Both the HUI3 and SF-6D were able to discriminate between patient groups differing in disease severity defined as predialysis versus dialysis dependent and depressive symptoms using a Beck Depression Inventory II score of ≥14 as the cutoff. The HUI3 was better able to discriminate greater depressive symptoms.
Conclusion:  The SF-6D and the HUI3 generate different preference-based scores for patients with CKD and any comparison between their scores should be made with caution. The HUI3 appears more suitable for measuring the health of populations with greater disability such as patients with CKD. It remains to be determined whether these differences will remain when one compares within-instrument differences in preference scores over time.     

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.     

Validation and Comparison of EuroQol and Short Form 6D in Chronic Prostatitis Patients

ObjectiveGeneric, preference-based health-related quality of life (HRQoL) instruments is increasingly used in health-care decision-making process. However, to our knowledge, no such HRQoL instrument has been validated or used in chronic prostatitis. We therefore aimed to assess and compare the psychometric properties of EuroQol (EQ-5D) and Short Form 6D (SF-6D) among chronic prostatitis patients in China.MethodsConsenting patients were interviewed using EQ-5D and SF-6D. Convergent and discriminative construct validities were examined with five and two a priori hypotheses, respectively. Sensitivity was compared using receiver operating characteristic (ROC) curves and relative efficiency (RE) statistics. Agreement between instruments was assessed with intra-class correlation coefficients and Bland–Altman plot, while factors affecting utility difference were explored with multiple liner regression models.ResultsIn 268 subjects, mean (SD) EQ-5D and SF-6D utility scores were comparable at 0.73 (0.15) and 0.75 (0.10), respectively. Five of the seven hypotheses for construct validity were fulfilled in both instruments. The areas under ROC of them all exceeded 0.5 (P < 0.001). SF-6D had 9.7–19.9% higher efficiency than EQ-5D at detecting the difference in chronic prostatitis symptom severity. Despite no significant difference in utility scores between two instruments, lack of agreement was observed with low intraclass correlation coefficient (0.218–0.630) and Bland–Altman plot analysis. Chronic prostatitis symptom severity significantly (P < 0.05) influenced differences in utility scores between EQ-5D and SF-6D.ConclusionsBoth EQ-5D and SF-6D are demonstrated to be valid and sensitive HRQoL measures in Chinese chronic prostatitis patients, with SF-6D showing better HRQoL dimension coverage, greater sensitivity, lower ceiling effect, and more rational distribution. Further research is needed to determine longitudinal response and reliability.     

Preference-Based Quality of Life of Patients on Renal Replacement Therapy: A Systematic Review and Meta-Analysis

Objectives:  Various utility measures have been used to assess preference-based quality of life of patients with end-stage renal disease (ESRD). The purposes of this study were to summarize the literature on utilities of hemodialysis (HD), peritoneal dialysis (PD), and renal transplantation (RTx) patients, to compare utilities between these patient groups, and to obtain estimates for quality-of-life adjustment in economic analyses.
Methods:  We searched the English literature for studies that reported visual analog scale (VAS), time trade-off (TTO), standard gamble (SG), EuroQol-5D (EQ-5D), and health utilities index (HUI) values of ESRD patients. We extracted patient characteristics and utilities and calculated mean utilities and 95% confidence intervals (CIs) for categories defined by utility measure and treatment modality using random-effects models.
Results:  We identified 27 articles that met the inclusion criteria. VAS articles were too heterogeneous to summarize quantitatively and we found only one study reporting HUI values. Thus, we summarized utilities from TTO, SG, and EQ-5D studies. Mean TTO and EQ-5D-index values were lower for dialysis compared to RTx patients, though not statistically significant for TTO values (TTO values: HD 0.61, 95% CI 0.54–0.68; PD 0.73, 95% CI 0.61–0.85; RTx 0.78, 95% CI 0.63–0.93; EQ-5D-index values: HD 0.56, 95% CI 0.49–0.62; PD 0.58, 95% CI 0.50–0.67; RTx 0.81, 95% CI 0.72–0.90). Mean HD versus PD associated TTO, EQ-5D-index and EQ-VAS values were not statistically significantly different.
Conclusion:  RTx patients tended to have a higher utility than dialysis patients. Among HD and PD patients, there were no statistically significant differences in utility.     

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.     

An assessment of validity and responsiveness of generic measures of health-related quality of life in hearing impairment

Purpose

This review examines psychometric performance of three widely used generic preference-based measures, that is, EuroQol 5 dimensions (EQ-5D), Health Utility Index 3 (HUI3) and Short-form 6 dimensions (SF-6D) in patients with hearing impairments.

Methods

A systematic search was undertaken to identify studies of patients with hearing impairments where health state utility values were measured and reported. Data were extracted and analysed to assess the reliability, validity (known group differences and convergent validity) and responsiveness of the measures across hearing impairments.

Results

Fourteen studies (18 papers) were included in the review. HUI3 was the most commonly used utility measures in hearing impairment. In all six studies, the HUI3 detected difference between groups defined by the severity of impairment, and four out of five studies detected statistically significant changes as a result of intervention. The only study available suggested that EQ-5D only had weak ability to discriminate difference between severity groups, and in four out of five studies, EQ-5D failed to detected changes. Only one study involved the SF-6D; thus, the information is too limited to conclude on its performance. Also evidence for the reliability of these measures was not found.

Conclusion

Overall, the validity and responsiveness of the HUI3 in hearing impairment was good. The responsiveness of EQ-5D was relatively poor and weak validity was suggested by limited evidence. The evidence on SF-6D was too limited to make any judgment. More head-to-head comparisons of these and other preference measures of health are required.     

A Review of the Methods Used to Generate Utility Values in NICE Technology Assessments for Children and Adolescents

ObjectiveThis review summarizes and critically examines methods used to generate utilities for child and adolescent health states in previous National Institute for Health and Care Excellence (NICE) technology assessments (TA) and highly specialized technology (HST) evaluations.MethodsWe identified all NICE TA and HST evaluations in which the licensed indication for the technology included people younger than 18 and included in the review all evaluations using a cost-utility analysis.ResultsThe review includes 40 TA and HST evaluations. Most assessments generated utility values with the EQ-5D scored using the adult version of the EQ-5D either exclusively (n = 16) or alongside other utility measures and direct elicitation methods of patient own utility (n = 17), although 7 did not use the EQ-5D. Eight assessments used both the EQ-5D child- and adolescent-specific preference-based measures: Health Utilities Index Mark 2 (n = 6), child- and adolescent-specific preference-based measure for atopic dermatitis (n = 1), and youth version of the EQ-5D (EQ-5D-Y) valued using the adult EQ-5D value set (n = 1) or generated using mapping and valued using the adult EQ-5D value set (n = 2). Some cost-utility analyses used age adjustment (utility subtractions, weights, and published mapping formulae) from the adult EQ-5D UK population norms to reflect the general population or disease-free health for children and adolescents (n = 9), and 1 assessment assumed full health (utility value of 1).ConclusionThe review found limited use of child and adolescent population-specific measures to generate health state utility values for children and adolescents in NICE technology assessments. Often assessments involve the use of an adult-specific measure to reflect the health of children.     

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.     

Evidence on the longitudinal construct validity of major generic and utility measures of health-related quality of life in teens with depression

Purpose

To examine the longitudinal construct validity in the assessment of changes in depressive symptoms of widely used utility and generic HRQL instruments in teens.

Methods

392 teens enrolled in the study and completed HRQL and diagnostic measures as part of the baseline interview. HRQL measures included EuroQol (EQ-5D-3L), Health Utilities Index Mark 2 (HUI2) and Mark 3 (HUI3), Quality of Well-Being Scale (QWB), Pediatric Quality of Life Inventory (PEDS-QL), RAND-36 (SF-6D), and Quality of Life in Depression Scale (QLDS). Youth completed follow-up interviews 12 weeks after baseline. Sixteen youth (4.1%) were lost to follow-up. We examined correlations between changes in HRQL instruments and the Children’s Depression Rating Scale-Revised (CDRS-R) and assessed clinically meaningful change in multi-attribute utility HRQL measures using mean change (MC) and standardized response mean (SRM) among youth showing at least moderate (20%) improvement in depression symptomology.

Results

Spearman’s correlation coefficients demonstrated moderate correlation between changes in CDRS-R and the HUI2 (r?=?0.38), HUI3 (r?=?0.42), EQ-5D-3L (r?=?0.36), SF-6D (r?=?0.39), and PEDS-QL (r?=?0.39) and strong correlation between changes in CDRS-R and QWB (r?=?0.52) and QLDS (r?=???0.71). Effect size results are also reported. Among multi-attribute utility measures, all showed clinically meaningful improvements in the sample of youth with depression improvement (HUI2, MC?=?0.20, SRM?=?0.97; HUI3, MC?=?0.32, SRM?=?1.17; EQ-5D-3L, MC?=?0.08, SRM?=?0.51; QWB, MC?=?0.11, SRM?=?0.86; and SF-6D, MC?=?0.12, SRM?=?1.02).

Conclusions

Findings support the longitudinal construct validity of included HRQL instruments for the assessment of change in depression outcomes in teens. Results of this study can help inform researchers about viable instruments to include in economic evaluations for this population.