Comparability of Patient-reported Health Status: Multicountry Analysis of EQ-5D Responses in Patients With Type 2 Diabetes

Time perspective profile and self-reported health on the EQ-5D

OBJECTIVES

Time perspective (TP) is a psychological construct that is associated with several health-related behaviours, including healthy eating, smoking and adherence to medications. In this study, we aimed to examine the associations of TP profile with self-reported health on the EQ-5D-5L and to detect which domains display response heterogeneity (cut-point shift) for TP.

METHODS

We conducted a secondary analysis of EQ-5D-5L data from a representative general population sample in Hungary (n = 996). The 17-item Zimbardo Time Perspective Inventory was used to measure individuals' TP on five subscales: past-negative, past-positive, present-fatalist, present-hedonist and future. The associations between TP subscales and EQ-5D-5L domain scores, EQ VAS and EQ-5D-5L index values were analysed by using partial proportional odds models and multivariate linear regressions.

RESULTS

Respondents that scored higher on the past-negative and present-fatalist and lower on the present-hedonist and future subscales were more likely to report more health problems in at least one EQ-5D-5L domain (p < 0.05). Adjusting for socio-economic and health status, three EQ-5D-5L domains exhibited significant associations with various TP subscales (usual activities: present-fatalist and future, pain/discomfort: past-negative and future, anxiety/depression: past-negative, present-fatalist, present-hedonist and future). The anxiety/depression domain showed evidence of cut-point shift.

CONCLUSIONS

This study identified response heterogeneity stemming from psychological characteristics in self-reported health on the EQ-5D-5L. TP seems to play a double role in self-reported health, firstly as affecting underlying health and secondly as a factor influencing one's response behavior. These findings increase our understanding of the non-health-related factors that affect self-reported health on standardized health status measures.

Decrements in health-related quality of life associated with adverse events in people with diabetes

AIM

To estimate the decrements in health-related quality of life (QoL) associated with a range of adverse events to inform assessments of the effects of diabetes treatments on QoL in contemporary clinical practice.

METHODS

Participants' QoL utility measures were derived from the five-level EuroQoL five-dimensional (EQ-5D-5L) questionnaires completed by 11 683 ASCEND participants (76% of 15 480 recruited). EQ-5D utility decrements associated with cardiovascular (myocardial infarction, coronary revascularization, transient ischaemic attack [TIA], ischaemic stroke, heart failure), bleeding (gastrointestinal [GI] bleed, intracranial haemorrhage, other major bleed), cancer (GI tract cancer, non-GI tract cancer), and microvascular events (end-stage renal disease [ESRD], amputation) were estimated using a linear regression model following adjustment for participants' sociodemographic and clinical risk factors.

RESULTS

Amputation was associated with the largest EQ-5D utility decrement (-0.206), followed by heart failure (-0.185), intracranial haemorrhage (-0.164), GI bleed (-0.091), other major bleed (-0.096), ischaemic stroke (-0.061), TIA (-0.057), and non-GI tract cancer (-0.026). We were unable to detect decrements in EQ-5D utility associated with myocardial infarction, coronary revascularization, GI tract cancer, or ESRD. EQ-5D utility was lower at older age, independent of other factors.

CONCLUSION

These estimated decrements in QoL associated with cardiovascular, bleeding, cancer, and other adverse events can inform assessments of the overall value of treatments in patients with diabetes.

Self-rated health scores predict mortality among people with type 2 diabetes differently across three different country groupings: findings from the ADVANCE and ADVANCE-ON trials

AIMS

To explore whether there is a different strength of association between self-rated health and all-cause mortality in people with type 2 diabetes across three country groupings: nine countries grouped together as 'established market economies'; Asia; and Eastern Europe.

METHODS

The ADVANCE trial and its post-trial follow-up were used in this study, which included 11 140 people with type 2 diabetes from 20 countries, with a median follow-up of 9.9 years. Self-rated health was reported on a 0-100 visual analogue scale. Cox proportional hazard models were fitted to estimate the relationship between the visual analogue scale score and all-cause mortality, controlling for a range of demographic and clinical risk factors. Interaction terms were used to assess whether the association between the visual analogue scale score and mortality varied across country groupings.

RESULTS

The visual analogue scale score had different strengths of association with mortality in the three country groupings. A 10-point increase in visual analogue scale score was associated with a 15% (95% CI 12-18) lower mortality hazard in the established market economies, a 25% (95% CI 21-28) lower hazard in Asia, and an 8% (95% CI 3-13) lower hazard in Eastern Europe.

CONCLUSIONS

Self-rated health appears to predict 10-year all-cause mortality for people with type 2 diabetes worldwide, but this relationship varies across groups of countries.

EORTC QLU-C10D value sets for Austria, Italy, and Poland

Objective

To develop Austrian, Italian, and Polish general population value sets for the EORTC QLU-C10D, a cancer-specific utility instrument based on the EORTC QLQ-C30, and to descriptively compare their index scores for distinct health states.

Methods

The QLU-C10D descriptive system comprises 10 health attributes and each can take on 4 levels. A standardised and pre-tested methodology has been applied for valuations including a web-based discrete choice experiment (DCE). It was administered in 1000 general population respondents per country recruited via online panels, aiming at representativeness for core socio-demographic variables.

Results

In all three countries, the attributes with the largest impact on utility were physical functioning, pain, and role functioning. Cancer-specific dimensions with the largest impact were nausea and fatigue or bowel problems. Utility values of the worst health state (i.e. severe problems on all 10 dimension) were -0.111 (Austria), 0.025 (Italy), and 0.048 (Poland). Country-specific utilities differed for a selection of health states across the continuum. Austrian utilities were systematically lower for moderately and severely impaired health states.

Conclusion

QLU-C10D cancer-specific utilities can now be calculated in three more countries. Differences between countries indicate that careful consideration is required when using non-country-specific value sets in economic evaluations.

Electronic supplementary material

The online version of this article (10.1007/s11136-020-02536-z) contains supplementary material, which is available to authorized users.

Observational analyses from ADVANCE and ADVANCE-ON

AIMS

To explain, and document, the epidemiological work associated with the action in diabetes and vascular disease: preterax and diamicron-modified release controlled evaluation (ADVANCE) clinical trial.

MATERIALS AND METHODS

ADVANCE was designed as a randomized controlled multicentre factorial trial in high-risk patients with diabetes. The two interventions were blood pressure lowering medications versus placebo, and intensive glucose control versus standard glucose control. Following termination of the trial, an observational study of surviving participants, able to join, was mounted: the ADVANCE - observational study (ADVANCE-ON). Other epidemiological analyses that were undertaken treated the trial as a cohort study, including using biomarkers from the blood samples taken from ADVANCE subjects as risk exposures.

RESULTS

More than 50 publications have reported epidemiological results from ADVANCE. The main results from ADVANCE-ON suggested attenuated benefits of ADVANCE's blood pressure lowering treatment on all-cause and cardiovascular death, but no such long-term benefits for intensive glucose control, although this did give persistent benefit for end-stage renal disease. The other epidemiological studies found, amongst other things, strong effects of NT-terminal pro-B-type natriuretic peptide and high-sensitivity cardiac troponin T on macrovascular events, microvascular events and all-cause death.

CONCLUSIONS

Embedding post-randomization and epidemiological analyses into clinical trials is worthwhile and can be highly productive in advancing scientific knowledge.

Comparing the EQ-5D-3 L and EQ-5D-5 L: studying measurement and scores in Indonesian type 2 diabetes mellitus patients

BACKGROUND

The EuroQoL five-dimensional instrument (EQ-5D) is the favoured preference-based instrument to measure health-related quality of life (HRQoL) in several countries. Two versions of the EQ-5D are available: the 3-level version (EQ-5D-3 L) and the 5-level version (EQ-5D-5 L). This study aims to compare specific measurement properties and scoring of the EQ-5D-3 L (3 L) and EQ-5D-5 L (5 L) in Indonesian type 2 diabetes mellitus (T2DM) outpatients.

METHODS

A survey was conducted in a hospital and two primary healthcare centres on Sulawesi Island. Participants were asked to complete the two versions of the EQ-5D instruments. The 3 L and 5 L were compared in terms of distribution and ceiling, discriminative power and test-retest reliability. To determine the consistency of the participants' answers, we checked the redistribution pattern, i.e., the consistency of a participant's scores in both versions.

RESULTS

A total of 198 T2DM outpatients (mean age 59.90 ± 11.06) completed the 3 L and 5 L surveys. A total of 46 health states for 3 L and 90 health states for 5 L were reported. The '11121' health state was reported most often: 17% in the 3 L and 13% in the 5 L. The results suggested a lower ceiling effect for 5 L (11%) than for 3 L (15%). Regarding redistribution, only 6.1% of responses were found to be inconsistent in this study. The 5 L had higher discriminative power than the 3 L version. Reliability as reflected by the index score was 0.64 for 3 L and 0.74 for 5 L. Pain/discomfort was the dimension mostly affected, whereas the self-care dimension was the least affected.

CONCLUSIONS

This study suggests that the 5 L-version of the EQ-5D instrument performs better than the 3 L-version in T2DM outpatients in Indonesia, regarding measurement and scoring properties. As such, our study supports the use of the 5 L as the preferred health-related quality of life measurement tool. We did not do a trial but this study was approved by the Medical Ethics Committee of Universitas Gadjah Mada Yogyakarta, Indonesia (document number KE/FK/1188/EC, 12 November 2014, amended 16 March 2015).

Patterns and trends in insulin initiation and intensification among patients with type 2 diabetes mellitus in the Western Pacific region

OBJECTIVE

Current and future estimates of the burden of diabetes for the Western Pacific (WP) region are among the highest in the world. Verifying Insulin Strategy and Initial Health Outcome Analysis (VISION) was an 18 month observational study that explored treatment approaches in patients with type 2 diabetes mellitus (T2DM) initiating insulin in the WP region.

METHODS

A total of 1065 patients aged ≥18 years with T2DM initiating insulin therapy in normal clinical course were enrolled from Hong Kong, Malaysia, Philippines, Taiwan and Thailand. Participants' data was recorded by the treating physicians. Patient-reported outcomes (PROs) were assessed using questionnaires completed by participants.

RESULTS

The mean age of patients was 57.2 years with mean glycosylated hemoglobin (HbA1c) of 10.0%. About 66% of patients had an HbA1c ≥9.0% at insulin initiation despite 74% of them being on two or more oral antidiabetic agents at the time of insulin initiation. Basal insulin was initiated in 72% and premixed insulin in 27% of patients. Changes in insulin therapy was observed in 63% of patients and, by the end of study, 28% achieved HbA1c levels of <7.5%. The proportion of patients completely satisfied with their insulin treatment increased over the study course and the quality of life (QoL) score increased from baseline to the study end.

CONCLUSION

As high HbA1C levels indicate a delayed start of insulin therapy, timely initiation and early intensification of insulin therapy is necessary in the region to achieve adequate glycemic control in time and prevent diabetes complications. Data from PROs suggests that the insulin treatment improves QoL in most patients.

Differential item functioning in quality of life measurement: An analysis using anchoring vignettes

Systematic differences in the ways that people use and interpret response categories (differential item functioning, DIF) can introduce bias when using self-assessments to compare health or quality of life across heterogeneous groups. This paper reports on an exploratory analysis involving the use of anchoring vignettes to identify DIF in a commonly used measure for assessing health-related quality of life - namely the EQ-5D. Using data from a bespoke (i.e. custom) survey that recruited a representative sample of 4300 respondents from the general Australian population in 2014 and 2015, we find that the assumptions of response consistency (RC) and vignette equivalence (VE) hold in a sub-sample of respondents aged 55-65 years (n = 914), which demonstrates that vignettes can appropriately identify DIF in EQ-5D reporting for this age group. We find that the EQ-5D is indeed subject to DIF, and that failure to account for DIF can lead to conclusions that are misleading when using the instrument to compare health or quality of life across heterogeneous groups. We also provide several important insights in terms of the identifying assumptions of RC and VE. We conclude that the implications of DIF could be of considerable importance, not only for outcomes research, but for funding decisions in healthcare more broadly given the strong reliance on patient-reported outcome measures in economic evaluations for health technology assessment.

An exploration of differences between Japan and two European countries in the self-reporting and valuation of pain and discomfort on the EQ-5D

PURPOSE

To investigate the systematic differences in the self-reporting and valuation of overall health and, in particular, pain/discomfort between three countries (England/UK, Japan, and Spain) on the EQ-5D.

METHODS

Existing datasets were used to explore differences in responses on the EQ-5D descriptive system between Japan (3L and 5L), the UK (3L), England (5L), and Spain (5L), particularly on the dimension of pain/discomfort. The role of different EQ dimensions in determining self-reported overall health scores for the EuroQol visual analog scale (EQ-VAS) was investigated using ordinary least squares regression. Time trade-off (TTO) results from Japanese and UK respondents for the EQ-5D-3L as well as Japanese and English respondents for the EQ-5D-5L were compared using t tests.

RESULTS

For the EQ-5D-3L, a higher percentage of respondents in Japan than in the UK reported 'no pain/discomfort' (81.6 vs 67.0%, respectively); for the EQ-5D-5L, the proportions were 79.2% in Spain, 73.2% in Japan, and 63-64% in England, after adjusting for age differences in samples. The 'pain/discomfort' dimension had the largest impact on respondents' self-reported EQ-VAS only for EQ-5D-3L in Japan. Using the EQ-5D-3L, Japanese respondents were considerably less willing to trade off time to avoid pain/discomfort than the UK respondents; for example, moving from health state, 11121 (some problems with pain/discomfort) to 11131 (extreme pain/discomfort) represented a decrement of 0.65 on the observed TTO value in the UK compared with 0.15 in Japan. Using the EQ-5D-5L, Japanese respondents were also less willing to trade off time to avoid pain/discomfort than respondents in England; however, the difference in values was much smaller than that observed using EQ-5D-3L data.

CONCLUSIONS

This study provides evidence of between-country differences in the self-reporting and valuation of health, including pain/discomfort, when using EQ-5D in general population samples. The results suggest a need for caution when comparing or aggregating EQ-5D self-reported data in multi-country studies.

Response-Scale Heterogeneity in the EQ-5D

This paper discusses two types of response-scale heterogeneity, which may impact upon the EQ-5D. Response-scale heterogeneity in reporting occurs when individuals systematically differ in their use of response scales when responding to self-assessments. This type of heterogeneity is widely observed in relation to other self-assessed measures but is often overlooked with regard to the EQ-5D. Analogous to this, preference elicitation involving the EQ-5D could be subject to a similar type of heterogeneity, where variations across respondents may occur in the interpretations of the levels (response categories) being valued. This response-scale heterogeneity in preference elicitation may differ from variations in preferences for health states, which have been observed in the literature. This paper explores what these forms of response-scale heterogeneity may mean for the EQ-5D and the potential implications for researchers who rely on the instrument as a measure of health and quality of life. We identify situations where they are likely to be problematic and present potential avenues for overcoming these issues. Copyright © 2016 John Wiley & Sons, Ltd.

Estimating Health-State Utility for Economic Models in Clinical Studies: An ISPOR Good Research Practices Task Force Report

Cost-utility models are increasingly used in many countries to establish whether the cost of a new intervention can be justified in terms of health benefits. Health-state utility (HSU) estimates (the preference for a given state of health on a cardinal scale where 0 represents dead and 1 represents full health) are typically among the most important and uncertain data inputs in cost-utility models. Clinical trials represent an important opportunity for the collection of health-utility data. However, trials designed primarily to evaluate efficacy and safety often present challenges to the optimal collection of HSU estimates for economic models. Careful planning is needed to determine which of the HSU estimates may be measured in planned trials; to establish the optimal methodology; and to plan any additional studies needed. This report aimed to provide a framework for researchers to plan the collection of health-utility data in clinical studies to provide high-quality HSU estimates for economic modeling. Recommendations are made for early planning of health-utility data collection within a research and development program; design of health-utility data collection during protocol development for a planned clinical trial; design of prospective and cross-sectional observational studies and alternative study types; and statistical analyses and reporting.

Changes in Quality of Life Associated with Complications of Diabetes: Results from the ADVANCE Study

OBJECTIVE

To measure the impact of complications on summary measures of health-related quality of life among people with type 2 diabetes.

METHODS

Patients participating in the Action in Diabetes and Vascular Disease:Preterax and Diamicron MR Controlled Evaluation (ADVANCE) trial were administered a health-related quality-of-life questionnaire, the three-level EuroQol five-dimensional questionnaire (EQ-5D-3L), on four occasions over a 5-year period. We used two-way fixed-effects longitudinal regression models to investigate the impact of incident diabetes complications (stroke, heart failure, myocardial infarction, ischemic heart disease, renal failure, blindness, and amputation) on EQ-5D-3L utility score (where 1 = perfect health), while controlling for characteristics of individuals that do not vary over time.

RESULTS

The effect of having any one of the seven complications was to reduce the EQ-5D-3L utility score by 0.054 (95% confidence interval 0.044-0.064), and this was not significantly affected by baseline age, sex, economic region, or the value set used to derive utilities. The complication with the largest disutility was amputation (0.122), followed by stroke (0.099), blindness (0.083), renal failure (0.049), heart failure (0.045), and myocardial infarction (0.026). Ischemic heart disease did not significantly reduce the utility score. Quality of life also declined with elapsed time-by an average of 0.006 per year, in addition to the effect of complications.

CONCLUSIONS

Common complications significantly reduce health-related quality of life. Utility scores derived from the EQ-5D-3L provide a potential measure that can be used to summarize patient-reported outcomes and inform health economic models. Prevention of complications is critical to reduce the progressive burden of declining quality of life for people with diabetes.

Comorbidity, health-related quality of life and self-care in type 2 diabetes: a cross-sectional study in an outpatient population

BACKGROUND

Comorbid conditions may be related (concordant) or unrelated (discordant) to diabetes. Comorbidity in patients with type 2 diabetes (T2DM) is associated with reduced health-related quality of life (HRQoL) and self-care.

AIM

To examine the impact of comorbidity on HRQoL and self-care in T2DM patients attending an outpatient setting.

METHODS

A cross-sectional questionnaire was sent to 498 patients with T2DM, aged 25-80 years, previously attending (August 2011-July 2012) an outpatient diabetes service in a Dublin hospital. The EuroQoL-5 Dimension (EQ-5D) and a modified summary of diabetes self-care activities scale were used to assess HRQoL and self-care, respectively. Comorbidity was assessed using a simplified version of the self-administered comorbidity Questionnaire. Mann-Whitney and Kruskal-Wallis tests were used to examine the association between EQ-5D index scores or self-care, and the number and type of comorbidities. Multiple linear regression, adjusting for age and sex, was used to examine the association between EQ-5D score, comorbidity score and type.

RESULT

EQ-5D scores decreased with an increasing number of comorbidities and with discordant comorbidity (P = 0.0001). Comorbidity type was associated with physical activity. The highest level of physical activity was reported in respondents with no comorbidity (median 4.5 IQR 3-6), while the lowest was in patients with both concordant and discordant comorbidity (median 2.5 IQR 0-5).

CONCLUSIONS

Health professionals should be aware of the fall in HRQoL associated with comorbidity. This should be taken into account in the management of patients. Patients with discordant comorbidity should be advised and supported to maintain levels of physical activity.

Testing for differential item functioning within the EQ-5D

We test for the presence of differential item functioning (DIF) in the EQ-5D health-related quality-of-life instrument, using data from a large clinical trial in acute stroke (ISRCTN 99414122). DIF occurs when subjects in different subsets of a sample respond differently to items in a measurement instrument, despite possessing the same latent traits. The data comprised 1462 patient records. We analyzed DIF specifically with respect to responses obtained from different geographical regions and responses obtained from proxies as opposed to the patients themselves. We mapped clinical outcome measures (scores from the modified Rankin Scale, the Barthel Index, and the Zung Depression scale) onto EQ-5D index scores and included dummy variables for proxy responses and for region of treatment (United Kingdom, Asia, rest of world). We predicted the level of problem severity reported on each of the EQ-5D's five constituent dimensions from the clinical measures and the dummy variables. For given clinical characteristics, proxies were more likely to report health problems than were the patients themselves, although the divergences were not sufficiently large to result in any significant difference in mean index scores between patient and proxy reports. However, the distributions of reported levels of problems for similar clinical states diverged significantly by region, and these translated into different index scores. The mean index score for UK responses was significantly higher than the mean index scores from Asia and the rest of the world.