Chapter 32 The measurement of health-related quality of life for use in resource allocation decisions in health care

Do We Understand Unmet Need? A Proposal to Use Length-Of-Life Equivalent (LOLE) as a Patient-Centric Measure of Unmet Need

Many decision-makers have emphasized the importance of leveraging patient experience data to measure unmet need. However, there is no standardized, patient-centric unmet need measure that formalizes how the value judgements inherent in such a measure should be made. Several initiatives have identified measuring unmet need as one of the primary uses of patient preference data. After reviewing how decision-makers define unmet need, this paper proposes that a thresholding method could be used to generate a standardized, patient-centric, disease-agnostic, quantitative unmet need estimate, length of life equivalent (LOLE). LOLE would address some of the limitations of current methods, including facilitating capture of the impact of disease beyond health-related quality of life, and being more sensitive to the impact of a disease on patients. However, the acceptability of LOLE raises questions for decision-makers, including: Is length of life equivalence the best common metric in which to express unmet need? Is it appropriate to rate a disease as having no unmet need if patients are unwilling to trade off life expectancy for improvements in their quality of life? Can LOLE be estimated for more complex disease profiles? Is thresholding the appropriate method to use to estimate LOLE? How should LOLE be integrated into decision-making, including the level of LOLE that defines different levels of unmet need? Further work could usefully address these questions with decision-makers.

Determinants of health-related quality of life in older people with chronic musculoskeletal pain: a cross-sectional study

BACKGROUND

This study aimed to identify the significant physical, psychological, and social determinants associated with EuroQuol-5D (EQ-5D) among Chinese older people with chronic musculoskeletal pain, and to evaluate how these determinants affected the five dimensions of EQ-5D.

METHOD

This is a cross-sectional study. Data were collected through a cohort involving 946 community-dwelling older people aged ≥ 60 with chronic musculoskeletal pain in Hong Kong. Selected independent variables were categorized into physical, psychological, and social domains. Physical variables included age, sex, body mass index (BMI), pain severity score, number of pain regions, the most painful site, and the number of comorbidities. Psychological variables included depression level measured using the 9-question Patient Health Questionnaire (PHQ-9), and anxiety level measured using the Generalized Anxiety Disorder Assessment (GAD-7). Social variables included living, marital, and social welfare recipient's status. The dependent variables comprised the index scores and the five dimensions of the EQ-5D descriptive system. Ordinal least squares (OLS) model and logistic regression model were used for data analysis.

RESULTS

The mean age of the participants was 67.1 (SD = 5.1), with 77.6% being female. Higher pain severity scores (beta (β) coefficient =-0.044, P < 0.001), depression scores (β=-0.007, P < 0.001) and higher anxiety scores (β=-0.01, P < 0.001) were associated with lower EQ-5D index scores. Specifically, knee pain (β=-0.061, P < 0.001) was significantly associated with lower EQ-5D index scores. Participants with higher pain severity and depression scores were more likely to report problems in most EQ-5D dimensions. Participants with anxiety primarily faced challenges related to mood, and those with knee pain were more likely to have problems with mobility and daily activities.

CONCLUSION

Among the selected determinants in our study, pain intensity, depression, anxiety, and knee pain were identified as key determinants associated with reduced HRQoL in older Chinese people with chronic musculoskeletal pain. Each of these determinants showed distinct associations with different dimensions of the EQ-5D, potentially informed resource allocation and the development of targeted interventions to improve the overall HRQoL of this specific population.

Use of Utility and Disability Weights in Economic Evaluation of Pediatric Vaccines

OBJECTIVE

To describe how utility weights and disability weights have been used in the context of quality-adjusted life-years (QALYs) and disability-adjusted life-years (DALYs)-based cost-effectiveness analysis (CEA) of pediatric vaccines for infectious diseases and assess the comparability between weights.

METHODS

A systematic review was conducted of CEAs of pediatric vaccines for 16 infectious diseases, published between January 2013 and December 2020 and using QALYs or DALYs as outcome measure. Data on values and sources of weights for the estimation of QALYs and DALYs were extracted from studies and compared across similar health states. Reporting was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

RESULTS

Out of 2154 articles identified, 216 CEAs met our inclusion criteria. Of the included studies, 157 used utility weights and 59 used disability weights in their valuation of health states. In QALY studies, the source, background, who's preferences (adults'/children's) were applied and adjustments made to utility weights were poorly reported. In DALY studies, the Global Burden of Disease study was most often referenced. Valuation weights for similar health states varied within QALY studies and between DALY and QALY studies, but no systematic differences were identified.

CONCLUSIONS

This review identified considerable gaps in the way valuation weights are used and reported on in CEA. The nonstandardized use of weights may lead to different conclusions about cost-effectiveness of vaccines and policy decisions.

Context matters for disability and priority setting for musculoskeletal diseases: revisiting the egalitarian approach to disability weights and disability-adjusted life-years

Health metrics have evolved with increasing sophistication. The disability-adjusted life-year (DALY) has emerged as a widely used metric. While DALYs vary between countries, the global disability weights (DWs) that are integral to the DALY ignore the potential impact of local factors on the burden of disease. Developmental dysplasia of the hip (DDH), a spectrum of hip pathologies, typically develops during early childhood and is a leading cause of early hip osteoarthritis. This paper explores the variability in the DW for DDH in relation to to local health environments using select health system indicators.The DW for DDH increases with decreasing income level of countries. The Human Development Index and the Gross Domestic Product per capita are both negatively correlated with (p<0.05) the DW for DDH per country. For the indicators surgical workforce, surgical procedures and hospital beds per 1000 population, there is a significant negative correlation in countries not meeting the minimum standard of that indicator (p<0.05), while for countries meeting that minimum standard, the correlation between DW for DDH and the respective indicator is not significantly different from zero.Consideration should be given to re-establishing the DWs for health entities in countries that do not meet the minimum standards of a functional health system. This would more accurately reflect the burden of disease from a functional perspective in LMICs, and perhaps allow for more informed priority setting within LMICs and for donors. The establishment of these DWs should not start from scratch; our data suggest that the variability in DWs due to context can most likely be modelled using health system and financial protection indicators already in use today.

Sociodemographic predictors of flourishing among older adults in rural and urban Mongolia

Flourishing is an eudaimonic dimension of psychological well-being associated with positive social and health outcomes. Determining correlates of health and well-being is critical for the development of evidence-based best practices, policies, and action plans that target older adults, especially in low- and middle-income countries where research on ageing, health and well-being is still scarce. The study aimed to determine the level of flourishing among older adults in Mongolia and to explore demographic and social factors that contribute to their flourishing in urban and rural areas of Mongolia. We used proportional quota sampling to select a non-probability sample of 304 community-dwelling older adults that reflected the national distribution of older age groups and rural/urban residency. We adapted and administered a widely used standardized questionnaire on flourishing and used multiple regression to establish correlates of flourishing. Study participants reported "very high" levels of flourishing; differences in median scores 53 for urban and 50 for rural older adults were significant. Sex ([Formula: see text], [Formula: see text]), level of education([Formula: see text], [Formula: see text]) and receive help with ADLs ([Formula: see text], [Formula: see text]) were associated with flourishing in rural areas, as were self-rated health ([Formula: see text], [Formula: see text]), number of social activities ([Formula: see text], [Formula: see text]),and friends network ([Formula: see text], [Formula: see text]) in urban areas. Despite facing many challenges to well-being, older adults in Mongolia reported high levels of flourishing. Those in urban areas had higher scores than those in rural areas and predictors of flourishing differed for these groups.

Association between 24-hour movement behaviors and health-related quality of life in children

PURPOSE

To assess the associations between adherence to 24-hour movement behaviors guidelines and child general health and functional status measured by health-related quality of life.

METHODS

The Longitudinal Study of Australian Children (2004-2016) a nationally representative sample with data available for children aged 2-15 years was used. Physical activity time, recreational screen time, and sleep time were calculated from time use diaries and classified as 'meeting guidelines' or 'not' based on the age-specific 24-h movement guidelines. Child general health and functional status were measured using the multidimensional Pediatric Quality of Life Inventory (PedsQL). Associations between meeting guidelines and PedsQL were assessed using linear mixed effects models.

RESULTS

8919 children were included. Each additional guideline met was associated with a 0.52 (95% confidence interval [CI] 0.39-0.65) increase in PedsQL total score. Compared with meeting no guidelines, the effect of meeting physical activity guidelines alone (β = 0.93, 95% CI 0.42-1.44) was larger compared to meeting screen (β = 0.66, 95% CI 0.06-1.27) or sleep time (β = 0.47, 95% CI 0.04-0.89) guidelines alone. The highest increment was observed in meeting both screen time and physical activity guidelines (β = 1.89, 95% CI 1.36-2.43). Associations were stronger in children from lower-income families (β for meeting all versus none = 2.88, 95% CI 1.77-3.99) and children aged 14-15 years (β = 4.44, 95% CI 2.49-6.40).

CONCLUSIONS

The integration of screen time and physical activity guidelines is associated with the highest PedsQL improvement. The association between guidelines adherence and PedsQL appears stronger for adolescents and those from low-income families.

Cost-effectiveness of a Province-wide Quality Improvement Initiative for Reducing Potentially Inappropriate Use of Antipsychotics in Long-Term Care in British Columbia, Canada

BACKGROUND

Potentially inappropriate use of antipsychotics (PIUA) raises serious concerns about safety, quality, and cost of care for residents in long-term care (LTC).

OBJECTIVE

This study aimed to estimate the cost-effectiveness of the Call for Less Antipsychotics in Long-Term Care (Clear) initiative compared with the status quo (pre-Clear, baseline).

METHODS

A model-based cost-utility analysis, from a public-payer perspective in British Columbia, was conducted using secondary data of residents in LTC homes from 2013 to 2019. Residents' health resource utilization and quality-adjusted life-year (QALY) measures were extracted from multiple administrative databases. Six Markov states were modelled for post-antipsychotic progression representing PIUA, appropriate use of antipsychotic, complete withdrawal, and death. The primary outcome was the incremental cost per QALY gained.

RESULTS

A cohort of 35,669 residents was included in the primary analysis. The Clear initiative, over 10 years, was estimated to have an incremental cost-effectiveness ratio (ICER) of CA$26,055 (2020 Canadian dollars) per QALY gained at an incremental cost of CA$5211 per resident and a QALY gain of 0.20. In the subgroup analyses, our findings were even more favourable for Clear wave 2 (ICER of CA$24,447 per QALY gained) and Clear wave 3 (ICER of CA$25,933 per QALY gained). At a willingness-to-pay of CA$50,000 per QALY gained, the probabilities of Clear waves 2 and 3 were 82% cost-effective.

CONCLUSION

This study demonstrated incremental costs and yielded favourable ICERs for Clear compared with the baseline. More research is needed to understand the level of support for individual care homes to sustain the Clear initiative in the long run.

Inflammatory biomarkers and cognitive functioning in individuals with euthymic bipolar disorder: exploratory study

BACKGROUND

Neurobiological research frequently implicates inflammatory and neurogenic components with core aspects of bipolar disorder. Even in periods of symptom remission (euthymia), individuals with bipolar disorder experience cognitive impairments, which are increasingly being proposed as an outcome for interventions; identifying biomarkers associated with cognitive impairment in people with bipolar disorder could advance progress in this therapeutic field through identifying biological treatment targets.

AIMS

We aimed to identify proteomic biomarker correlates of cognitive impairment in individuals with euthymic bipolar disorder.

METHOD

Forty-four adults with a bipolar disorder diagnosis in euthymia underwent a battery of cognitive assessments and provided blood for biomarkers. We examined a comprehensive panel of inflammatory and trophic proteins as putative cross-sectional predictors of cognition, conceptualised according to recommended definitions of clinically significant cognitive impairment (binary construct) and global cognitive performance (continuous measure).

RESULTS

A total of 48% of the sample met the criteria for cognitive impairment. Adjusting for potentially important covariates, regression analyses identified lower levels of three proteins as significantly and independently associated with cognitive deficits, according to both binary and continuous definitions (interleukin-7, vascular endothelial growth factor C and placental growth factor), and one positively correlated with (continuous) global cognitive performance (basic fibroblast growth factor).

CONCLUSIONS

This study identifies four candidate markers of cognitive impairment in bipolar disorder, none of which have been previously compared with cognitive function in participants with bipolar disorder. Pending replication in larger samples and support from longitudinal studies, these markers could have implications for treating cognitive dysfunction in this patient population.

Does the order of total hip replacement and lumbar spinal stenosis surgery influence patient-reported outcomes: An observational register study

Patients with degenerative hip and lumbar spine disorders requiring surgery in both locations is fairly common in clinical practice. We investigated if the order of total hip replacement (THR) and lumbar spinal stenosis surgery (LSSS) influences patient-reported outcomes (PROs). We used data from the Swedish Hip Arthroplasty Register (SHAR) and the Swedish Spine Register (Swespine), on patients operated with THR and LSSS in years 2002 to 2012. To increase the probability of having symptomatic disorders in both locations at the time of the first surgery, we only included patients with both LSSS and THR performed within 2 years. Linear and logistic regression analyses adjusted for age, sex, preoperative PROs, and time between surgeries were used to investigate the association between order of surgeries and the generic PRO measurements EQ-5D and EQ VAS. Eighty-four patients had THR prior to LSSS and 171 patients LSSS prior to THR. Linear regression showed that LSSS prior to THR was associated with higher EQ-5D index (B = 0.09, 95% confidence interval [CI] 0.03-0.16) and EQ VAS (B = 5.6, 95% CI 0.4-10.9) 1 year after the last surgery. Logistic regression showed that the odds ratio [OR] for not having any problems in the "pain" (OR = 3.0, 95% CI 1.5-6.3) and "anxiety/depression" (OR = 2.3, 95% CI 1.3-4.1) dimensions were higher for LSSS before THR. In our cohort, LSSS before THR was associated with better health-related quality of life outcomes compared to the reverse order. The results from our cohort can be helpful in a clinical situation where the physician gives advice to an individual patient when choosing the order of procedures. However, further studies are necessary in order to confirm these results in other cohorts. At present, standard of care remains that order of surgery should be individualized for each patient, with guidance from the operating surgeons.

Cognitive remediation therapy for patients with bipolar disorder: A randomised proof-of-concept trial

OBJECTIVES

Cognitive remediation therapy (CRT) may benefit people with bipolar disorder type I and II for whom cognitive impairment is a major contributor to disability. Extensive research has demonstrated CRT to improve cognition and psychosocial functioning in people with different diagnoses, but randomised trials of evidenced therapy programmes are lacking for bipolar disorders. The Cognitive Remediation in Bipolar (CRiB) study aimed to determine whether an established CRT programme is feasible and acceptable for people with bipolar disorders.

METHODS

This proof-of-concept, single-blind randomised trial recruited participants aged 18-65 with bipolar disorder, not currently experiencing an episode. They were 1:1 block randomised to treatment-as-usual (TAU) with or without individual CRT for 12 weeks. The partly computerised CRT programme ("CIRCuiTS") was therapist-led and is evidence-based from trials in those with psychotic illnesses. Data were collected and analysed by investigators blinded to group allocation. The main outcomes (week 13 and 25) examined participant retention, intervention feasibility and putative effects of CRT on cognitive and psychosocial functioning via intention-to-treat analyses.

TRIAL REGISTRATION

ISRCTN ID32290525.

RESULTS

Sixty participants were recruited (02/2016-06/2018) and randomised to CRT (n = 29) or TAU (n = 31). Trial withdrawals were equivalent (CRT n = 2/29; TAU n = 5/31). CRT satisfaction indicated high acceptability. Intention-to-treat analyses (N = 60) demonstrated greater improvements for CRT- than TAU-randomised participants: at both week 13 and 25, CIRCuiTS participants showed larger improvements in the following domains (week 25 effect sizes reported here): IQ (SES = 0.71, 95% CI [0.29,1.13]), working memory (SES = 0.70, 95% CI [0.31,1.10]), executive function (SES = 0.93, 95% CI [0.33,1.54]), psychosocial functioning (SES = 0.49, 95% CI [0.18,0.80]) and goal attainment (SES = 2.02, 95% CI [0.89,3.14]). No serious adverse events were reported.

CONCLUSIONS

CRT is feasible for individuals with bipolar disorders and may enhance cognition and functioning. The reported effect sizes from this proof-of-concept trial encourage further investigation in a definitive trial.

Social tariffs and democratic choice-Do population-based health state values reflect the will of the people?

In economic evaluations of health technologies, health outcomes are commonly measured in terms of quality-adjusted life years (QALYs). QALYs are the product of time and health-related quality of life. Health-related quality of life, in turn, is determined by a social tariff, which is supposed to reflect the public's preference over health states. This study argues that, because of the tariff's role in the societal decision-making process, it should not be understood as merely an operational (statistical) definition of health, but as a major instrument of democratic participation. I outline what implications this might have for both the method used to aggregate individual preferences, and the set of individuals whose preferences should count. Alternative tariff specifications and decision rules are explored, and future research directions are proposed.

New method of measuring subjective well-being: prospective validation study of the 'Daily Experience Sampling Questionnaire' (DESQ) in patients with psoriasis and healthy subjects in Germany

OBJECTIVES

To validate the newly developed Daily Experience Sampling Questionnaire (DESQ) that measures affective subjective well-being (SWB). The DESQ is an end-of-day diary in which respondents retrospectively rate their SWB at six different, randomly determined moments; it is completed over 1 week. The DESQ shall provide an alternative or complementary approach to existing methods of near-time SWB measurement (experience sampling, Day Reconstruction Method). The primary research objective was to determine criterion validity of the DESQ.

DESIGN

Prospective, non-interventional study.

SETTING

Participants were recruited in Hamburg, Germany, at a specialised outpatient clinic (patients) and via different channels (healthy participants).

PARTICIPANTS

101 adults with diagnosed and stable psoriasis (46 women, 55 men); 105 adults without psoriasis (49 women, 56 men).

PRIMARY AND SECONDARY OUTCOME MEASURES

Participants completed the DESQ for 3 weeks. In weeks 2 and 3, they also performed experience sampling. Criterion validity was determined by weekwise intraclass correlations (ICC) between both methods. Sensitivity to change was determined by the correlation between changes in both methods from weeks 2 to 3. For convergent validity, related concepts such as life satisfaction were measured. Retest reliability was determined using DESQ values of weeks 2 and 3.

RESULTS

Criterion validity was excellent (ICC: patients=0.86, 95% CI 0.81 to 0.91; healthy participants=0.86, 95% CI 0.79 to 0.91). Sensitivity to change was r=0.57 and r=0.56, respectively. Correlations with convergent criteria were mostly significant and higher in constructs more proximal to SWB. The ICC indicating retest reliability was 0.77 in patients (95% CI 0.68 to 0.84) and 0.81 in healthy participants (95% CI 0.73 to 0.86).

CONCLUSIONS

The DESQ is a valid, reliable and feasible instrument for SWB measurement in people with psoriasis and healthy people. Its approach of end-of-day evaluations of single moments may also lend itself to the measurement of other highly time-variant constructs such as pain, fatigue or depression.

Health economic evaluation of gene replacement therapies: methodological issues and recommendations

Objective: To provide recommendations for addressing previously identified key challenges in health economic evaluations of Gene Replacement Therapies (GRTs), including: 1) the assessment of clinical effectiveness; 2) the valuation of health outcomes; 3) the time horizon and extrapolation of effects beyond trial duration; 4) the estimation of costs; 5) the selection of appropriate discount rates; 6) the incorporation of broader elements of value; and 7) affordability. Methods: A literature review on economic evaluations of GRT was performed. Interviews were conducted with 8 European and US health economic experts with experience in evaluations of GRT. Targeted literature reviews were conducted to investigate further potential solutions to specific challenges. Recommendations: Experts agreed on factors to be considered to ensure the acceptability of historical cohorts by HTA bodies. Existing prospective registries or, if not available, retrospective registries, may be used to analyse different disease trajectories and inform extrapolations. The importance of expert opinion due to limited data was acknowledged. Expert opinion should be obtained using structured elicitation techniques. Broader elements of value, beyond health gains directly related to treatment, can be considered through the application of a factor to inflate the quality-adjusted life years (QALYs) or a higher cost-effectiveness threshold. Additionally, the use of cost-benefit analysis and saved young life equivalents (SAVE) were proposed as alternatives to QALYs for the valuations of outcomes of GRT as they can incorporate broader elements of value and avoid problems of eliciting utilities for paediatric diseases. Conclusions: While some of the limitations of economic evaluations of GRT are inherent to limited clinical data and lack of experience with these treatments, others may be addressed by methodological research to be conducted by health economists.

Exploring health-related quality of life and frailty in older adults based on the Korean Frailty and Aging Cohort Study

PURPOSE

The study aimed to analyze the association between frailty and health-related quality of life (HRQOL) based on the Korean Frailty and Aging Cohort Study.

METHODS

In this cross-sectional study, 2905 adults aged 70 to 84 years were enrolled. Frailty was determined according to the Fried frailty index. HRQOL was measured using the 5-level EuroQol questionnaire (EQ-5D-5L) and the 12-item Short-Form Health Survey version 2 (SF-12). Hierarchical linear regressions were conducted to examine the relationship between frailty and HRQOL and a logistic regression analysis was performed to estimate odds ratios of frailty status in the scores of the lowest quartiles in each scale.

RESULTS

Of the total respondents, 7.8% were frail, 47.0% were pre-frail, and 45.2% were robust. Frail respondents had significantly lower HRQOL scores than robust respondents, especially for EQ-5D-5L utility weights (0.74 vs 0.93). Frailty was strongly associated with decreased HRQOL in both physical and mental component summary of SF-12 (p < 0.001). Both pre-frail and frail states were related to greater odds of scoring in the bottom 25% of HRQOL scales compared to the non-frail state (p < 0.0001).

CONCLUSION

Frailty was associated with declined HRQOL in Korean older adults. This result recommends raising awareness about identifying and preventing frailty for better quality of life in the Korean elderly population.

A comparison of individual and collective decision making for standard gamble and time trade-off

Quality-Adjusted Life-Years (QALYs) are typically derived from individual preferences over health episodes. This paper reports the first experimental investigation into the effects of collective decision making on health valuations, using both time trade-off (TTO) and standard gamble (SG) tasks. We investigated collective decision making in dyads, by means of a mixed-subjects design where we control for learning effects. Our data suggest that collective decision making has little effect on decision quality, as no effects were observed on decision consistency and monotonicity for both methods. Furthermore, QALY weights remained similar between individual and collective decisions, and the typical difference in elicited weights between TTO and SG was not affected. These findings suggest that consulting with others has little effect on health state valuation, although learning may have. Additionally, our findings add to the literature of the effect of collective decision making, suggesting that no such effect occurs for TTO and SG.

Advanced therapy medicinal products and health technology assessment principles and practices for value-based and sustainable healthcare

BACKGROUND

Advanced therapy medicinal products (ATMPs) are beginning to reach European markets, and questions are being asked about their value for patients and how healthcare systems should pay for them.

OBJECTIVES

To identify and discuss potential challenges of ATMPs in view of current health technology assessment (HTA) methodology-specifically economic evaluation methods-in Europe as it relates to ATMPs, and to suggest potential solutions to these challenges.

METHODS

An Expert Panel reviewed current HTA principles and practices in relation to the specific characteristics of ATMPs.

RESULTS

Three key topics were identified and prioritised for discussion-uncertainty, discounting, and health outcomes and value. The panel discussed that evidence challenges linked to increased uncertainty may be mitigated by collection of follow-on data, use of value of information analysis, and/or outcomes-based contracts. For discount rates, an international, multi-disciplinary forum should be established to consider the economic, social and ethical implications of the choice of rate. Finally, consideration of the feasibility of assessing the value of ATMPs beyond health gain may also be key for decision-making.

CONCLUSIONS

ATMPs face a challenge in demonstrating their value within current HTA frameworks. Consideration of current HTA principles and practices with regards to the specific characteristics of ATMPs and continued dialogue will be key to ensuring appropriate market access.

CLASSIFICATION CODE

I.

Patients with a previous total hip replacement experience less reduction of back pain following lumbar back surgery

The coexistence of degenerative disorders from the hip joint and the lumbar spine, known as "the hip-spine syndrome," is a common encounter in clinical practice. These degenerative conditions may cause similar symptoms which often entail diagnostic challenges in determining the origin of pain. Lumbar back surgery (LBS) with fusion and/or decompression, and total hip replacement (THR) are both often successful interventions. However, the knowledge is limited about the post-operative patient-reported outcome (PRO) following LBS in the presence of a prior THR. The aims of this study were to compare 1-year post-operative patient-reported outcome measures (PROMs) following lumbar back surgery (LBS) in patients with and without a prior total hip replacement (THR). Data from Swespine and the Swedish Hip Arthroplasty Register were linked in order to identify the study group of patients with THR prior to LBS. The study group (n = 220) and a matched control group (n = 220) with isolated LBS was defined by using a step-wise selection process. Linear- and logistic regression analyses adjusted for age, sex and pre-operative PROMs demonstrated that THR prior to LBS was associated with worse back-pain (VAS) at 1-year follow-up (B = 5.3, 95%CI: 0.3;10.3). However, previous THR did not influence the EQ-5D index (B = 0.01, 95%CI: -0.05;0.06), EQ VAS (B = -3.0, 95%CI: -6.9;1.0), leg pain (B = 1.5, 95%CI: -4.0;7.0), Oswestry Disability Index (B = 2.6, 95%CI: -0.5;5.6) or satisfaction (OR = 1.1, 97.5%CI 0.7;1.6). This knowledge is important to communicate prior to LBS in order to set proper expectations on surgical outcomes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2484-2490, 2018.

Quality of Life After Radical Cystectomy

Approximately 1 in 5 new cases of clinically localized bladder cancer is muscle invasive and requires the patient to choose from 1 of 2 prevailing options for treatment: radical cystectomy or radiation to the bladder. However, these treatments are associated with detrimental effects on patient well-being and quality of life, particularly with respect to functional independence, urinary and sexual function, social and emotional health, body image, and psychosocial stress. Compared with the literature on other malignancies like breast or prostate cancer, high-quality studies evaluating the effects of bladder cancer treatment on quality of life are lacking.

Right from the start: protocol for a pilot study for a randomised trial of the New Baby Programme for improving outcomes for children born to socially vulnerable mothers

BACKGROUND

Children born to mothers who experience social complexity (e.g. substance misuse, intimate partner violence, mental ill health, a history of maltreatment) are at increased risk for a range of adverse outcomes at birth and during development. Home visiting programmes have been advocated as a strategy for improving outcomes for disadvantaged mothers and children, such as the Nurse-Family Partnership for young, socially disadvantaged first-time mothers. However, no evidence-based programme is available for multiparous women or older first-time mothers. The New Baby Programme was developed in Northern Ireland. It augments the universal health visiting service available in the UK with a content designed to promote maternal health and well-being in pregnancy, maximise secure attachments of children and parents and enhance sensitive parenting and infant cognitive development.

METHODS/DESIGN

This pilot study is designed to investigate whether it is possible to recruit and retain socially vulnerable mothers in a randomised trial that compares the effects of the New Baby Programme with standard antenatal and postnatal care. Feasibility issues include the referral/recruitment pathway (including inclusion and exclusion criteria), the consent and randomisation, the ability to maintain researcher blinding, the acceptability of the intervention to participants, and the feasibility and acceptability of the outcome measures. The results of the study will inform a definitive phase-3 RCT.

DISCUSSION

Trials of complex social interventions often encounter challenges that lead to the trial being abandoned (e.g. because of problems in recruitment) or present considerable analytic challenges relating to dropout, attrition and bias. This pilot study aims to maximise the chances of successful implementation.

TRIAL REGISTRATION

ISRCTN35456296 retrospectively registered.

Lumbar surgery prior to total hip arthroplasty is associated with worse patient-reported outcomes

Aims

The aims of this study were to describe the prevalence of previous lumbar surgery in patients who undergo total hip arthroplasty (THA) and to investigate their patient-reported outcomes (PROMs) one year post-operatively.

Patients and Methods

Data from the Swedish Hip Arthroplasty Register and the Swedish Spine Register gathered from 2002 to 2013 were merged to identify a group of patients who had undergone lumbar surgery before THA (n = 997) and a carefully matched one-to-one control group. We investigated differences in the one-year post-operative PROMs between the groups. Linear regression analyses were used to explore the associations between previous lumbar surgery and these PROMs following THA. The prevalence of prior lumbar surgery was calculated as the ratio of patients identified with previous lumbar surgery between 2002 and 2012, and divided by the total number of patients who underwent a THA in 2012.

Results

The prevalence of lumbar surgery prior to THA in 2012 was 3.5% (351 of 10 082). Linear regression analyses showed an association with more pain (B = 4.35, 95% confidence interval (CI) 2.57 to 6.12), worse EuroQol (EQ)-5D index, (B = -0.089, 95% CI -0.112 to -0.066), worse EQ VAS (B = -6.75, 95% CI -8.58 to -4.92), and less satisfaction (B = 6.04, 95% CI 4.05 to 8.02).

Conclusion

Lumbar spinal surgery prior to THA is associated with less reduction of pain, worse health-related quality of life, and less satisfaction one year after THA. This is useful information to share in the decision-making process and may help establish realistic expectations of the outcomes of THA in patients who also have previously undergone lumbar spinal surgery. Cite this article: Bone Joint J 2017;99-B:759–65.

Patient and general public preferences for health states: A call to reconsider current guidelines

In economic evaluations of health care interventions, benefits are often expressed in terms of Quality-Adjusted Life-Years (QALYs). The QALY comprises length and quality of life into one measure which allows cross-disease comparability. The quality adjustment of the QALY is based on preferences for health states. An important normative choice is the question whose preferences for states of health we wish to capture. The answer to this question is directly related to the normative question regarding the appropriate maximand in health care decisions. Currently, preferences are commonly derived from the general public, rather than from actual patients. This choice, which can have large consequences on final outcomes of economic evaluations, has always been a topic of debate. This paper clarifies and furthers the discussion regarding the appropriate source of preferences for health state valuations, acknowledges the plurality of different perspectives, and argues that health economic guidelines could require analysis of benefit in terms of QALYs based on both patient and general public preferences.

The Cognitive Remediation in Bipolar (CRiB) pilot study: study protocol for a randomised controlled trial

Background

People with bipolar disorder often show difficulties with cognitive functioning, and though these difficulties are identified as important targets for intervention, few treatment options are available. Preliminary evidence suggests that cognitive remediation therapy (a psychological treatment proven beneficial for people diagnosed as having schizophrenia) is helpful for people with bipolar disorders. We are conducting a pilot trial to determine whether individual, computerised, cognitive remediation therapy (CRT) for people with bipolar disorder 1) increases cognitive function; 2) improves global functioning, goal attainment and mood symptoms; 3) is acceptable and feasible for participants; and 4) can be addressed in a comprehensive, larger, randomised, controlled trial.

Methods/design

The study is designed as a two-arm, randomised, controlled trial comparing cognitive remediation therapy with treatment-as-usual (TAU) for euthymic bipolar patients. Participants are eligible to take part if aged between 18 and 65 with a diagnosis of bipolar disorder (type I) and currently in euthymic state, and no neurological, substance or personality disorder diagnoses. Sixty participants will be recruited (mainly through secondary and tertiary care) and will be block-randomised to receive either treatment-as-usual alone or in addition to a 12-week course of cognitive remediation therapy totalling 20–40 therapy hours. The intervention will comprise regular sessions with a therapist and computer-based training. Research assessments will take place before and after the intervention period and at a 12-week follow-up, and will include evaluation of neuropsychological, symptom-related, demographic and social factors, as well as collecting qualitative data regarding CRT expectations and satisfaction. Intention-to-treat analyses will examine the efficacy of cognitive remediation therapy primarily on cognition and additionally on functioning, quality of life and mood symptoms. Furthermore, we will examine the acceptability of CRT and undertake a preliminary health economics analysis to ascertain the cost of delivering the intervention.

Discussion

The results of this trial will provide valuable information about whether cognitive remediation therapy may be beneficial for people diagnosed with bipolar disorder in a euthymic state.

Trial Registration

ISRCTN registry, ISRCTN32290525. Registered on 2 March 2016

Health inequalities in the Netherlands: trends in quality-adjusted life expectancy (QALE) by educational level

BACKGROUND

Quality-adjusted life expectancy (QALE) has been proposed as a summary measure of population health because it encompasses multiple health domains as well as length of life. However, trends in QALE by education or other socio-economic measure have not yet been reported. This study investigates changes in QALE stratified by educational level for the Dutch population in the period 2001-2011.

METHODS

Using data from multiple sources, we estimated mortality rates and health-related quality of life (HRQoL) as functions of age, gender, calendar year and educational level. Subsequently, predictions from these regressions were combined for calculating QALE at ages 25 and 65. QALE changes were decomposed into effects of mortality and HRQoL.

RESULTS

In 2001-2011, QALE increased for men and women at all educational levels, the largest increases being for highly educated resulting in a widening gap by education. In 2001, at age 25, the absolute QALE difference between the low and the highly educated was 7.4 healthy years (36.7 vs. 44.1) for men and 6.3 healthy years (39.5 vs. 45.8) for women. By 2011, the QALE difference increased to 8.1 healthy years (38.8 vs. 46.9) for men and to 7.1 healthy years (41.3 vs. 48.4) for women. Similar results were observed at age 65. Although the gap was largely attributable to widening inequalities in mortality, widening inequalities in HRQoL were also substantial.

CONCLUSIONS

In the Netherlands, population health as measured by QALE has improved, but QALE inequalities have widened more than inequalities in life expectancy alone.

The measurement of disability weights for 18 prevalent acute poisoning conditions

BACKGROUND

Disability weights (DWs) are used in disease burden studies, with the calculation of the weight of the disability as years lived with disability versus years of lost life accounting for mortalities. Currently, there is a single DW score available for poisoning, which is considered to be a single health state. This makes it difficult to evaluate the differing burdens of poisonings involving various substances/conditions in comparison with other health states in countries with different patterns of substance abuse. The aim of this study is therefore to estimate the DWs of 18 common poisonings based on the expert elicitation method.

METHODS

A panel of 10 medical clinicians who were familiar with the clinical aspects of different poisonings estimated the DWs of 50 health states by interpolating them on a calibrated Visual Analogue Scale. The DWs of some poisonings, such as alcohol, cannabis and heroin, had been estimated in previous studies and so were used to determine the external consistency of our panel. As a matter of routine, the DWs could vary on a scale between 0 (best health state) and 1 (worst health state).

RESULTS

Statistical analysis showed that both the internal (Cronbach's α = 0.912) and external consistency of the panel were acceptable. The DWs for the different poisonings were estimated along a range from 0.830 for severe aluminium phosphide to 0.022 for mild benzodiazepine.

CONCLUSIONS

Different poisonings should be weighted differently since they vary widely. Unfortunately, they are currently all weighted the same.

Did the health of the Dutch population improve between 2001 and 2008? Investigating age- and gender-specific trends in quality of life

Although many countries' populations have experienced increasing life expectancy in recent decades, quality of life (QoL) trends in the general population have yet to be investigated. This paper investigates whether QoL changed for the general Dutch population over the period 2001-2008. A beta regression model was employed to address specific features of the QoL distribution (i.e., boundedness, skewness, and heteroskedasticity), as well non-linear age and time trends. Quality-adjusted life expectancy (QALE) was calculated by combining model estimates of mean QoL with mortality rates provided by Statistics Netherlands. Changes in QALE were decomposed into those changes caused by QoL changes and those caused by mortality-rate changes. The results revealed a significant increase in QoL over 2001-2008 for both genders and most ages. For example, QALE for a man/woman aged 20 was found to have increased by 2.3/1.9 healthy years, of which 0.6/0.8 was due to QoL improvements.

How Can Measures of Subjective Well-Being Be Used to Inform Public Policy?

The debate surrounding the use of subjective measures of well-being for policy purposes has intensified in recent years. Many social scientists are arguing that the time is right for policymakers to extend their traditional focus on material well-being and economic development to include the impact policies have on how people think and feel about their lives. However, policymakers may have many legitimate goals beyond making people happy. In this article, we begin by presenting three archetypal accounts of well-being that policymakers could use to guide policy (mental-state, objective-list, and desire-fulfillment accounts) and discussing some of the normative and methodological limitations of each. We discuss how a subjective (mental-state) approach could be used to aid the achievement of objective-list and desire-fulfillment policy goals. We then consider ways in which a subjective approach may benefit policymakers in its own right, such as by aiding the valuation of hard-to-quantify costs and benefits, providing a standard unit of measurement for comparisons of well-being across domains, and helping to set policy defaults. We conclude with a discussion of some of the remaining measurement issues and general policy implications.

The effect of hypoglycemia on health-related quality of life: Canadian results from a multinational time trade-off survey

OBJECTIVE

The aim of this study was to investigate the impact of hypoglycemia according to severity and time of onset on health-related quality of life (HRQoL) in a Canadian population.

METHODS

Time trade-off (TTO) methodology was used to estimate health utilities associated with hypoglycemic events in a representative sample of the Canadian population. A global analysis conducted in the United Kingdom, Canada, Germany and Sweden has been published. The present Canadian analysis focuses on 3 populations: general, type 1 and type 2 diabetes. Using a web-based survey, participants (>18 years) assessed the utility of 13 different health states (severe, non-severe, daytime and nocturnal hypoglycemia at different frequencies) using a scale from 1 (perfect health) to 0 (death). The average disutility value for each type of event was calculated.

RESULTS

Of 2258 participants, 1696 completers were included in the analysis. A non-severe nocturnal hypoglycemic event was associated with a significantly greater disutility than a non-severe daytime event (-0.0076 vs. -0.0056, respectively; p=0.05), while there was no statistically significant difference between severe nocturnal and severe daytime events (-0.0616 vs. -0.0592; p=0.76). Severe hypoglycemia was associated with greater disutility than non-severe hypoglycemia (p<0.0001). Similar trends were reported in participants with diabetes.

CONCLUSIONS

The findings presented here show that any form of hypoglycemia had a negative impact on HRQoL in a Canadian population. Nocturnal and/or severe hypoglycemia had a greater negative impact on HRQoL compared with daytime and/or non-severe events. This highlights the importance of preventing the development and nocturnal manifestation of hypoglycemia in patients with diabetes.

Qualitative and Quantitative Analysis of Interviewer Help Answering the Time Tradeoff

OBJECTIVES

The time tradeoff (TTO) is an important method to directly obtain health utilities. Challenges of the TTO are, among others, "nontraders" and illogical answers. In TTO interviews, these challenges are resolved by the interviewer. In web-based TTOs, training procedures and logical checks are used based on the views of the researchers. As web-based TTOs will be used more often in the future, we investigated how respondents arrive at their ratings to determine the help they require.

METHODS

In 2 earlier studies performed by this research group, respondents valued 6 EQ-5D states on a TTO. Respondents were asked to think out loud, and all interviews were audiotaped. A random selection of these interviews were transcribed and double-coded by two independent raters, using a priori and inductive coding until saturation was reached. Based on the retrieved mistakes and comments, a list of frequently asked questions (FAQ) was developed.

RESULTS

In total, 91 interviews were coded. In all, 85% made at least 1 mistake, 41% made a misreading/miscalculation, 70% misunderstood the tradeoff, 27% misunderstood the EQ-5D dimensions, 29% misunderstood the scenario, 45% made a comment about the TTO, and 43% expressed frustration. More misunderstandings were reported in the Peeters study, which was performed in a realistic setting, whereas the van Osch study was conducted in a more ideal setting. Misunderstandings of the scenario were mosly reported by patients.

CONCLUSIONS

Almost all respondents need interviewer help. This may have implications for the validity of interviewer-based TTO elicitations when social acceptability bias is an issue or with explicit hypothesis and the interviewer is not blinded. The FAQ list can be used to standardize interviewer help or as a help function in a web-based TTO.

Does the process of deliberation change individuals' health state valuations? An exploratory study using the person trade-off technique

BACKGROUND

This article explores two gaps in the health state valuation literature: the effect of processes and the stability of health state valuations, and the existence of preexisting valuations. Stability in health state valuations over time depends on whether preferences are considered to be preexisting (axiom of completeness) and therefore can be gathered reliably, or are constructed during consideration and debate. Under the former, changes in revealed preferences are evidence of poor reliability; under the latter, it is a function of the deliberative process.

METHODS

This study explores the effect of deliberation on health state valuations elicited by using the person trade-off technique . Quantitative analysis was used to explore whether respondents changed their responses following deliberation and the impact of change on aggregate health state values. Qualitative methods were used to explore respondents' views on the elicitation process and the impact of deliberation on their responses.

RESULTS

Following discussion and deliberation, 74% of the participants changed their person trade-off valuations and this did have an impact on the aggregate valuations. The qualitative analysis lends some support to the construction of preference assumption.

CONCLUSIONS

The results from this exploratory study challenge the notion that individuals have preexisting health state preferences and call for further detailed research in this area. Furthermore, it raises concerns over current practices around preference elicitation exercises, which have tended to be carried out as a solitary exercise without allowing time for respondents to reflect and deliberate on their decisions.

The way that you do it? An elaborate test of procedural invariance of TTO, using a choice-based design

The time tradeoff (TTO) method is often used to derive Quality-Adjusted Life Year health state valuations. An important problem with this method is that results have been found to be responsive to the procedure used to elicit preferences. In particular, fixing the duration in the health state to be valued and inferring the duration in full health that renders an individual indifferent, causes valuations to be higher than when the duration in full health is fixed and the duration in the health state to be valued is elicited. This paper presents a new test of procedural invariance for a broad range of time horizons, while using a choice-based design and adjusting for discounting. As one of the known problems with the conventional procedure is the violation of constant proportional tradeoffs (CPTO), we also investigate CPTO for the alternative TTO procedure. Our findings concerning procedural invariance are rather supportive for the TTO procedure. We find no violations of procedural invariance except for the shortest gauge duration. The results for CPTO are more troublesome: TTO scores depend on gauge duration, reinforcing the evidence reported when using the conventional procedure.

A direct method for measuring discounting and QALYs more easily and reliably

Time discounting and quality of life are two important factors in evaluations of medical interventions. The measurement of these two factors is complicated because they interact. Existing methods either simply assume one factor given, based on heuristic assumptions, or invoke complicating extraneous factors, such as risk, that generate extra biases. The authors introduce a method for measuring discounting (and then quality of life) that involves no extraneous factors and that avoids distorting interactions. Their method is considerably simpler and more realistic for subjects than existing methods. It is entirely choice based and thus can be founded on economic rationality requirements. An experiment demonstrates the feasibility of this method and its advantages over classical methods.

Endogenous patient responses and the consistency principle in cost-effectiveness analysis

In addition to incurring direct treatment costs and generating direct health benefits that improve longevity and/or health-related quality of life, medical interventions often have further or "unrelated" financial and health impacts, raising the issue of what costs and effects should be included in calculating the cost-effectiveness ratio of an intervention. The "consistency principle" in medical cost-effectiveness analysis (CEA) requires that one include both the cost and the utility benefit of a change (in medical expenditures, consumption, or leisure) caused by an intervention or neither of them. By distinguishing between exogenous changes directly brought about by an intervention and endogenous patient responses to the exogenous changes, and within a lifetime utility maximization framework, this article addresses 2 questions related to the consistency principle: 1) how to choose among alternative internally consistent exclusion/inclusion rules, and 2) what to do with survival consumption costs and earnings. It finds that, for an endogenous change, excluding or including both the cost and the utility benefit of the change does not alter cost-effectiveness results. Further, in agreement with the consistency principle, welfare maximization implies that consumption costs and earnings during the extended life directly caused by an intervention should be included in CEA.

Disability weights for suicidal thoughts and non-fatal suicide attempts

BACKGROUND

Although there are disability weights available for a wide range of health states, these do not include suicidality. This makes it difficult to evaluate the severity of suicidality in comparison with other health states. The aim of this study therefore is to estimate disability weights for suicidal thoughts and for mental distress involved in non-fatal suicide attempts.

METHODS

A Dutch expert panel of sixteen medical practitioners who were knowledgeable about suicidality estimated disability weights (DWs) for twelve health states by interpolating them on a calibrated Visual Analogue Scale. The DWs for ten of these health states had been estimated in previous studies and were used to determine the external consistency of the panel. The other two concerned health states for suicidal thoughts and non-fatal suicide attempts. The resulting DWs could vary between 0 (best imaginable health state) and 1 (worst imaginable health state).

RESULTS

Both internal (Cronbach's α = 0.98) and external consistency of the panel were satisfactory. The DWs for suicidal thoughts and non-fatal suicide attempts were estimated to be 0.36 and 0.46 respectively.

LIMITATIONS

The panel was relatively small, which resulted in broad confidence intervals.

CONCLUSIONS

Suicidal thoughts are considered to be as disabling as alcohol dependence and severe asthma. The mental distress involved in non-fatal suicide attempts is thought to be comparable in disability to heroin dependence and initial stage Parkinson's. These results demonstrate the severity of suicidality.

Is risk attitude outcome specific within the health domain?

The aim of this study is to examine whether individuals' risk attitude for life years differ from their risk attitude for quality of life. The study also investigates two different framing effects, an order and sequence effect, and the interaction between risk attitude and time preferences. The results showed that individuals tended to be risk averse with respect to the gamble involving risk of immediate death and risk seeking with respect to the other health gambles. Varying the order of the questions or the sequence of full health and ill-health did not seem to systematically bias the estimates.

Inconsistencies in TTO and VAS values for EQ-5D health states

BACKGROUND

Most EQ-5D health states can be ordered logically. When people assign values to different health states, they may violate this logical order, which can be seen as inconsistencies.

OBJECTIVE

The aim of this study was to assess the effect of inconsistently valued EQ-5D health states on mean visual analog scale (VAS) and time trade-off (TTO) values. The authors also examined the effect of removing respondents with high numbers of inconsistent states on the estimation of tariffs, which is used to interpolate values to all possible EQ-5D states from the direct valuation of a subset of states.

METHOD

Data from the Dutch EQ-5D valuation study were used. A representative sample of 309 Dutch adults valued 17 EQ-5D health states by VAS and TTO. A state was valued inconsistently when it had a higher value than at least 1 logically better state. Mean values of groups with various numbers of inconsistently valued states were compared.

RESULTS

Of the respondents, 65% had inconsistencies for VAS and 89% for TTO. The mean VAS values of consistent respondents tend to be lower. For TTO, those with inconsistencies gave lower values. Removing data of respondents with the highest number of inconsistently valued states for VAS (13%) and TTO (9%) did not result in statistically significant different coefficients in the estimated tariff using all data.

CONCLUSION

The majority of respondents valued at least 1 state inconsistently. For both VAS and TTO, the presence of these inconsistencies did not affect the estimated tariffs.

Estimating Preference Scores in Conventional and Home Nocturnal Hemodialysis Patients

Previous studies have reported higher quality of life in patients who receive home nocturnal hemodialysis (HNHD) than conventional in-center hemodialysis (IHD). The optimal method for eliciting preferences from dialysis patients remains undefined, and there may be unique methodologic concerns in this population. Patients' preferences for IHD (n = 20) and HNHD (n = 24) were studied using the standard gamble (SG), time trade-off (TTO), and modified willingness to pay (WTP) methods. This report describes experience with operationalizing these three techniques in this population. A higher preference for HNHD was found with all measures, with significant differences observed with the SG (HNHD: median 0.79 [interquartile range (IQR) 0.67 to 0.95]; IHD: median 0.60 [IQR 0.20 to 0.82]; P = 0.031) and WTP (HNHD: median 0.50 [IQR 0.40 to 0.68]; IHD: median 0.20 [IQR 0.20 to 0.38]; P < 0.001). SG and TTO scores were moderately correlated but not with WTP. In addition, qualitative issues arose during TTO and WTP interviews that seemed to influence the interpretation of these preference scores. In the TTO, time willing to trade became oriented toward the next pivotal life event, with a failure of the requirement for a constant proportional time trade-off. WTP preferences were oriented toward the smallest survival stipend. These issues represent range restriction biases. No significant issues arose during the SG interviews. HNHD patients expressed a greater preference for current health than IHD patients. The operational performance of SG was good in this study, whereas biases and methodologic concerns were identified with the TTO and WTP in this population.

On the aggregation of health status measures

In the present paper, we address the problem of finding conditions under which aggregation of individual health status measurements (e.g. QALYs) is meaningful in the sense that there is a universal unit of measurement for health. The problem is studied in a model where different aspects of health take the form of Lancasterian characteristics to be produced by the individuals using commodities obtained in the market. For a meaningful unit of measurement to exist, marginal rates of substitution between different aspects of health should not differ among individuals, and for this to happen in an equilibrium of the economy considered, certain assumptions of separability (of technology and/or preferences) must be satisfied. This means that universal measures of health will be meaningful only if there are not too many spillovers in achieving different aspects of health.

Choice-Based Evaluation for the Improvement of Upper-Extremity Function Compared With Other Impairments in Tetraplegia

OBJECTIVES

To assess preference of reconstructive treatment of upper extremities in subjects with tetraplegia compared with preference of treatment of 3 other impairments and to determine the effect of subjects' characteristics on preference of upper-extremity reconstruction.

DESIGN

Survey.

SETTING

Two specialized spinal cord injury centers in the Netherlands.

PARTICIPANTS

A consecutive sample of 47 patients with tetraplegia in stable condition.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The quality weight of 5 tetraplegic health states determined with the time trade-off technique and expressed as a single value (the "utility") on a scale between 0 (worst possible situation) and 1 (best possible situation).

RESULTS

The response rate was 92%. The utility of tetraplegia +/- standard deviation was .57+/-.30. The utilities of tetraplegia without impairment in one of the following functions were .69+/-.33 for sexuality, .69+/-.33 for standing/walking, .63+/-.31 for bladder and bowel function, and .65+/-.32 for upper-extremity function. The differences between these utilities and the utility of tetraplegia were significant (P<.05). No significant differences were found between the utilities of the impairments. Improvement of a specific impairment contributed between 14% and 28% to the potential overall gain in the tetraplegic health state utility.

CONCLUSIONS

The combination of impairments determines the low utility of the tetraplegic health state. No priority for improvement of any of the investigated impairments was found. This emphasizes the need for the meticulous selection of patients for treatment of specific conditions. Further research should try to determine the crucial factors in the decision-making process of patients for specific interventions.

Adjusting to changes in health: implications for cost-effectiveness analysis

This article introduces a model in which individuals incur adjustment costs associated with adaptations made following changes in their health. With adjustment costs, patients' preferences for health states depend on their initial health in such a way that improvements have lower values than corresponding deteriorations. Improvement and deterioration must therefore be treated asymmetrically in CEA. The inclusion of adjustment costs also has other consequences. It produces a more stringent CEA criterion, and may affect the relative rankings of interventions. In addition, when health is multi-dimensional, and adjustment costs are incorporated, we show that a consensus on even ordinal rankings of health states becomes impossible.

A consistency test of the time trade-off

This paper tests the internal consistency of time trade-off utilities. We find significant violations of consistency in the direction predicted by loss aversion. The violations disappear for higher gauge durations. We show that loss aversion can also explain that for short gauge durations time trade-off utilities exceed standard gamble utilities. Our results suggest that time trade-off measurements that use relatively short gauge durations, like the widely used EuroQol algorithm, are affected by loss aversion and lead to utilities that are too high.

A test of the QALY model when health varies over time

Quality-adjusted life years (QALYs) estimate the utility derived from health profiles by taking account of life expectancy and quality of life. In applying QALYs to situations where health varies over time, it is usual to assume that we can add the utilities from constituent health states. This paper investigates the QALY approach to combining health states over time using two tests. The first test rejects additive independence, the central assumption of the QALY model, for individual respondents. The second test is equivocal. The tests are, therefore, unable to conclusively reject the QALY approach to combining health states over time.

The validity of time trade-off values in calculating QALYs: constant proportional time trade-off versus the proportional heuristic

In order to calculate quality adjusted life years (QALYs) from time trade-off (TTO) responses, individual preferences are required to satisfy the constant proportional time trade-off (CPTTO) assumption. Respondents who use a simple proportional heuristic may appear to satisfy CPTTO but will in fact generate preference reversals for states that are associated with a maximal endurable time (MET). Using data from 91 respondents, the study reported here examines the extent to which valuations satisfy the CPTTO assumption and the extent to which they might be generated by the proportional heuristic. The results suggest that respondents are using a proportional heuristic that casts doubt on the validity of using the TTO method to calculate QALYs for health states that are associated with MET preferences.