Measuring utilities by the time trade-off method in Tunisian rheumatoid arthritis patients

The effect of religion on the perception of health states among adults in the United Arab Emirates: a qualitative study

OBJECTIVES

Investigate how religion may affect the perception of health states among adults in the United Arab Emirates and the implications for research on self-reported health and quality of life and the use of values in cost-effectiveness analysis.

DESIGN

Qualitative analysis of short-structured interviews with adult Emiratis carried out by a market research agency.The COREQ criteria have been used where appropriate to guide the reporting of our findings.

SETTING

Participants were recruited from shopping malls and other public places in the cities of Al Ain and Abu Dhabi.

PARTICIPANTS

Two hundred adult Emiratis broadly representative of the Emirati population in terms of age and gender.

RESULTS

Eighty one per cent of participants said that their perception of health states was influenced by their spiritual or religious beliefs. The two overarching themes that seemed to explain or classify these influences were 'fatalism' and 'preservation of life'. Subthemes included powerlessness to change what is preordained by God, fear of disability (particularly diminished mobility) and appreciation of health and life and the requirement to look after one's health. A final theme was that of acceptance, with respondents expressing a willingness to endure suffering and disability with patience in the expectation of rewards in the hereafter.

CONCLUSIONS

Our results emphasise the need for further work to establish locally relevant value sets for Muslim majority countries in the Middle East and elsewhere for use in health technology assessment decision-making, rather than relying on value sets from other regions.

The time horizon matters: results of an exploratory study varying the timeframe in time trade-off and standard gamble utility elicitation

INTRODUCTION

The purpose of this study was to examine whether the time horizon of time trade-off (TTO) and standard gamble (SG) utility assessment influences utility scores and discrimination between health states.

METHODS

In two phases, UK general population participants rated three osteoarthritis health states in TTO and SG procedures with two time horizons: (1) 10-year and (2) a time horizon derived from self-reported additional life expectancy (ALE). The two time horizons were compared in terms of mean utilities and discrimination among health states.

RESULTS

In Phase 1, the 10-year tasks were completed by 80 participants, 35 of whom also completed utility assessment with the ALE. In Phase 2, all 101 participants completed procedures with both time horizons. Utility scores tended to be lower with the ALE than the 10-year, a difference that was statistically significant for two health states with SG in Phase 1 (P < 0.05), two health states with TTO in Phase 2 (P < 0.01), and one health state with SG in Phase 2 (P < 0.001). In Phase 1, rates of discrimination between mild and moderate osteoarthritis health states were significantly higher with the ALE than the 10-year (TTO: P = 0.03; SG: P = 0.001). This pattern of discrimination was similar in Phase 2.

DISCUSSION

Results suggest that the time horizon could influence utility scores and discrimination among health states. When designing utility evaluations, researchers should carefully consider the time horizon so that the value of health states is accurately represented in cost-utility models.

Applicability of patient utilities as measures of overall quality of life in rheumatoid arthritis clinical trials

OBJECTIVE

The aim was to determine whether the time trade-off (TTO) and standard gamble utilities can detect treatment-related improvement in overall quality of life in patients with active RA.

METHODS

We measured TTO and standard gamble utilities in 192 patients before and after escalation of anti-rheumatic treatment in a prospective longitudinal study. We also examined associations between changes in utilities and patient-reported improvement during the study, and with EULAR responses.

RESULTS

Mean TTO at baseline was 0.68 (median 0.82) and mean standard gamble 0.80 (median 0.93). Both utilities improved significantly with treatment. Standardized response means, a measure of responsiveness, were 0.37 for the TTO and 0.20 for the standard gamble, and comparable to those of two mental health measures and the CRP, but lower than other RA activity measures. Changes in utilities were not significantly associated with patient-reported improvement. The standard gamble, but not the TTO, had a graded association with EULAR responses.

CONCLUSION

Utilities by the TTO and standard gamble were able to detect improvement in overall quality of life with anti-rheumatic treatment in patients with active RA, suggesting applicability in clinical trials. The standard gamble was associated with reference measures of improvement, although not as strongly as measures of RA activity, as expected with its generic orientation.

The impact of visual impairment on health-related quality of life in rural Africa

PURPOSE

To assess the impact of visual impairment (VI) on utility values in Sub-Saharan Africa and compare findings with other studies from low- and high-income countries.

METHODS

Patients with normal vision and various levels of VI were recruited from a secondary eye clinic in rural Kenya and interviewed using time trade-off (TTO). VI was classified using the World Health Organization definition of (normal vision, visual acuity ≥20/60, VI 20/80-20/200, severe VI 20/240-20/400, and blindness <20/400).

RESULTS

Mean age of the total sample (N = 303) was 50.3 years (standard deviation, SD, ±18.17 years), and 51.5% of patients were male. Most were small-scale farmers and illiteracy was high at 40%. Mean TTO scores per group were: normal vision 0.93 (SD ± 0.10), VI 0.88 (SD ± 0.14), severe VI 0.86 (SD ± 0.13), blindness 0.73 (SD ± 0.17; p ≤ 0.001). Lower TTO scores were independently associated with worse visual acuity (p ≤ 0.001), longer duration of disease (p ≤ 0.001) and illiteracy (p = 0.011), but not with cause of VI, age, sex, marital status, socioeconomic status, or systemic comorbidities in multivariate analyses. Overall, TTO scores were considerably higher than those reported from high-income countries at similar levels of VI.

CONCLUSION

In this rural African population, duration and extent of vision loss, rather than cause, socioeconomic factors and comorbidities affected vision-related quality of life. Our findings underline the importance of providing sight-restoring treatment as timely as possible and the necessity of enhancing rehabilitation efforts for those with non-curable eye diseases.

Health state valuation in low- and middle-income countries: a systematic review of the literature

OBJECTIVE

Cost-utility analysis is widely used in high-income countries to inform decisions on efficient health care resource allocation. Cost-utility analysis uses the quality-adjusted life-year as the outcome measure of health. High-income countries have undertaken health state valuation (HSV) studies to determine country-specific utility weights to facilitate valuation of health-related quality of life. Despite an evident need, however, the extent of HSVs in low- and middle-income countries (LMICs) is unclear.

METHODS

The literature was searched systematically by using four databases and additional Web searches to identify HSV studies carried out in LMICs. The Preferred Reporting System for Systematic Reviews and Meta-Analysis (PRISMA) strategy was followed to ensure systematic selection of the articles.

RESULTS

The review identified 17 HSV studies from LMICs. Twelve studies were undertaken in upper middle-income countries, while lower middle- and low-income countries contributed three and two studies, respectively. There were 7 generic HSV and 10 disease-specific HSV studies. The seven generic HSVs included five EuroQol five-dimensional questionnaire, one six-dimensional health state short form (derived from short-form 36 health survey), and one Assessment of Quality of Life valuations. Time trade-off was the predominant valuation method used across all studies.

CONCLUSIONS

This review found that health state valuations from LMICs are uncommon and utility weights are generally unavailable for these countries to carry out health economic evaluation. More HSV studies need to be undertaken in LMICs to facilitate efficient resource allocation in their respective health systems.

Construct validity of the interview time trade-off and computer time trade-off in patients with rheumatoid arthritis: a cross-sectional observational pilot study

BACKGROUND

The Time Trade-Off (TTO) is a widely used instrument for valuing preference-based health-related quality of life (HRQoL). The TTO reveals preferences for own current health ('utilities') on a scale anchored between death (0) and perfect health (1). Limited information on the external validity of the TTO is available. Aim of this pilot study was to examine the construct validity of both an interview TTO and a computer-based TTO in patients with rheumatoid arthritis (RA).

METHODS

Thirty patients visiting the outpatient rheumatology clinic participated. Construct validity was assessed by measuring convergent and discriminative validity. Convergent validity was assessed by calculating Spearman's correlations between the utilities obtained from the TTOs and pain, general health (rating scales), health-related quality of life (SF-36 and SF-6D) and functional status (HAQ-DI). Discriminative power of both TTO measures was determined by comparing median utilities between worse and better health outcomes.

RESULTS

Correlations of both TTO measures with HRQoL, general health, pain and functional status were poor (absolute values ranging from .05 to .26). Both TTOs appeared to have no discriminative value among groups of RA patients who had a worse or better health status defined by six health outcome measures. About one-third of respondents were zero-traders on each of the TTO measures. After excluding zero-traders from analysis, the correlations improved considerably.

CONCLUSIONS

Both the interview TTO and computer TTO showed poor construct validity in RA patients when using measures of HRQol, general health, pain and functional status as reference measures. Possibly, the validity of the TTO improves when using an anchor that is more realistic to RA patients than the anchor 'death'.

Feasibility and Reliability of the Annual Profile Method for Deriving QALYs for Short-Term Health Conditions

Introduction . When health varies over time, the standard quality-adjusted life year model operates under the assumptions of time utility independence within each health state and additive independence between health states. These assumptions can be relaxed by an integral assessment of disease severity over time. The authors present the annual profile method (APM), which values health profiles on a 1-year base, and test the APM for feasibility, consistency, and test-retest reliability. Methods . A population panel, general practitioners, medical advisers, and a panel of the Dutch Consumers Association valued vignettes for 46 disease stages using the visual analog scale (VAS) and time tradeoff (TTO) methods. Vignettes contained disease-specific information, a generic description (EQ-6D5L), a description of the disease course over time, and a visual representation of the disease. Feasibility was tested by missing and inconsistent responses. Consistency between and within panels was tested with a generalizability study, analysis of variance, and standard correlation coefficients. Test-retest reliability was tested with a generalizability study and intra-class correlation coefficients. Results . Missing and inconsistent responses were < 2.6 %. The valuations were consistent across panels, with generalizability coefficients of 0.78 (VAS) and 0.64 (TTO). Within the main population panel, internal consistency was satisfactory and the influence of background characteristics negligible. Test-retest reliability was high, with generalizability coefficients of 0.90 (VAS) and 0.72 (TTO). Conclusion . Feasibility and reliability of the APM for realistic health profiles are good to excellent. The APM is a promising step to bridge the gap between the quality-adjusted life year methodology and clinical reality.