Alastair Canaway’s journal round-up for 10th June 2019

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

Analytic considerations in applying a general economic evaluation reference case to gene therapy. Value in Health Published 17th May 2019

For fledgling health economists starting in the world of economic evaluation, the NICE reference case is somewhat of a holy text. If in doubt, check the reference case. The concept of a reference case for economic evaluation has been around since the first US Panel on Cost-Effectiveness in Health and Medicine in 1996 and NICE has routinely used its own reference case for well over a decade. The primary purpose of the reference case is to improve the quality and comparability of economic evaluations by standardising methodological practices. There have been arguments made that the same methods are not appropriate for all medical technologies, particularly those in rare diseases or where no treatment currently exists. The focus of this paper is on gene therapy: a novel method that inserts genetic material into cells (as opposed to a drug/surgery) to treat or prevent disease. In this area there has been significant debate as to the appropriateness of the reference case and whether a new reference case is required in this transformative but expensive area. The purpose of the article was to examine the characteristics of gene therapy and make recommendations on changes to the reference case accordingly.

The paper does an excellent job of unpicking the key components of economic evaluation in relation to gene therapy to examine where weaknesses in current reference cases may lie. Rather than recommend that a new reference case be created, they identify specific areas that should be paid special attention when evaluating gene therapy. Additionally, they produce a three part checklist to help analysts to consider what aspects of their economic evaluation they should consider further. For those about to embark on an economic evaluation of a gene therapy intervention, this paper represents an excellent starting point to guide your methodological choices.

Heterogeneous effects of obesity on mental health: evidence from Mexico. Health Economics [PubMed] [RePEc] Published April 2019

The first line of the ‘summary’ section of this paper caught my eye: “Obesity can spread more easily if it is not perceived negatively”. This stirred up contradictory thoughts. From a public health standpoint we should be doing our utmost to prevent increasing levels of obesity and their related co-morbidities, whilst simultaneously we should be promoting body positivity and well-being for mental health. Is there a tension here? Might promoting body positivity and well-being enable the spread of obesity? This paper doesn’t really answer that question, instead it sought to investigate whether overweight and obesity had differing effects on mental health within different populations groups.

The study is set in Mexico which has the highest rate of obesity in the world with 70% of the population being overweight or obese. Previous research suggests that obesity spreads more easily if not perceived negatively. This paper hypothesises that this effect will be more acute among the poor and middle classes where obesity is more prevalent. The study aimed to reveal the extent of the impact of obesity on well-being whilst controlling for common determinants of well-being by examining the impact of measures of fatness on subjective well-being, allowing for heterogeneous effects across differing groups. The paper focused only on women, who tend to be more affected by excess weight than men (in Mexico at least).

To assess subjective well-being (SWB) the General Health Questionnaire (GHQ) was used whilst weight status was measured using waist to height ratio and additionally an obesity dummy. Data was sourced from the Mexican Family and Life Survey and the baseline sample included over 13,000 women. Various econometric models were employed ranging from OLS to instrumental variable estimations, details of which can be found within the paper.

The results supported the hypothesis. They found that there was a negative effect of fatness on well-being for the rich, whilst there was a positive effect for the poor. This has interesting policy implications: policy attempt to reduce obesity may not work if excess weight is not perceived to be an issue. The findings in this study imply that different policy measures are likely necessary for intervening in the wealthy and the poor in Mexico. The paper offers several explanations as to why this relationship may exist, ranging from the poor having lower returns from healthy time (nod to the Grossman model), to differing labour market penalties from fatness due to different job types for the rich and the poor.

Obviously there are limits to the generalisability of these findings, however it does raise interesting questions about how we should seek to prevent obesity within different elements of society, and the unintended consequences that shifts in attitudes may have.

ICECAP-O, the current state of play: a systematic review of studies reporting the psychometric properties and use of the instrument over the decade since its publication. Quality of Life Research [PubMed] Published June 2019

Those who follow the methodological side of outcome measurement will be familiar with the capability approach, operationalised by the ICECAP suite of measures amongst others. These measures focus on what people are able to do, rather than what they do. It is now 12-13 years since the first ICECAP measure was developed: the ICECAP-O designed for use in older adults. Given the ICECAP measures are now included within the NICE reference case for the economic evaluation of social care, it is a pertinent time to look back over the past decade to assess whether the ICECAP measures are being used and, if so, to what degree and how. This systematic review focusses on the oldest of the ICECAP measures, the ICECAP-O, and examines whether it has been used, and for what purpose as well as summarising the results from psychometric papers.

An appropriate search strategy was deployed within the usual health economic databases, and the PRISMA checklist was used to guide the review. In total 663 papers were identified, of which 51 papers made it through the screening process.

The first 8 years of the ICECAP-O’s life is characterised by an increasing amount of psychometric studies, however in 2014 a reversal occurred. Simultaneously, the number of studies using the ICECAP-O within economic evaluations has slowly increased, surmounting the number examining the psychometric properties, and has increased year-on-year in the three years up to 2018. Overall, the psychometric literature found the ICECAP-O to have good construct validity and generally good content validity with the occasional exception in groups of people with specific medical needs. Although the capability approach has gained prominence, the studies within the review suggest it is still very much seen as a secondary instrument to the EQ-5D and QALY framework, with results typically being brief with little to no discussion or interpretation of the ICECAP-O results.

One of the key limitations to the ICECAP framework to date relates to how economists and decision makers should use the results from the ICECAP instruments. Should capabilities be combined with time (e.g. years in full capability), or should some minimum (sufficient) capability threshold be used? The paper concludes that in the short term, presenting results in terms of ‘years of full capability’ is the best bet, however future research should focus on identifying sufficient capability and establishing monetary thresholds for a year with sufficient capability. Given this, whilst the ICECAP-O has seen increased use over the years, there is still significant work to be done to facilitate decision making and for it to routinely be used as a primary outcome for economic evaluation.

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Paul Mitchell’s journal round-up for 1st January 2018

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

Does the approach to economic evaluation in health care depend on culture, values and institutional context? European Journal of Health Economics [PubMedPublished 5th December 2017

In last week’s round-up we looked at a paper that attempted to develop guidance for costing across European economic evaluations, even when the guidelines across countries vary as to what should and should not be included in an economic evaluation. Why is it that there is such variation in health economic evaluation methods across countries? Why are economic outcomes like quality-adjusted life years (QALYs) standard practice in some countries yet frowned upon in others? This editorial argues that cultures, values and institutional context play a role in the economic evaluation methodologies applied across countries. It does so by comparing five large European countries in terms of 1. the organisation and governance of the agencies undertaking health technology assessments (HTAs) and economic evaluation, 2. the methods used for economic evaluation, and 3. the use of HTA and economic evaluation in decision making. The authors argue that due to differences in these areas across countries, it is difficult to see how a “one size fits all” economic evaluation framework can be implemented, when health care systems, their regulations and social values towards health care differ. An argument is presented that where greater social value is placed on horizontal equity (equal treatment of equals) over vertical equity (unequal treatment of unequals), the QALY outcome is more likely to be applied in such countries. They argue that of the five largest European countries, the German efficiency frontier model of economic analysis may offer the best off-the-shelf option for countries like the United States who also have similar qualms about the use of QALYs in decision making. However, it may be the case that current economic evaluations lack international application due to other reasons beyond those notable considerations raised in this paper.

Reconciling ethical and economic conceptions of value in health policy using the capabilities approach: a qualitative investigation of Non-Invasive Prenatal Testing. Social Science & Medicine [PubMed] [RePEcPublished 16th November 2017

The capability approach, initially developed by economist and philosopher Amartya Sen, provides an alternative evaluative framework to welfare economics, shifting the focus on individual welfare away from utility and preferences, towards a person’s freedom to do and be valuable things to their life. It has more recently been used as a critique of the current approach to health economic evaluations, specifically what aspects of quality of life are included in the economic outcome, where the current measurement tools used in the generation of QALYs have been argued to have too narrow a focus on health outcomes, with a number of capability measures now developed as alternatives. This study, on the other hand, applies the capability approach to tackle health technologies that pose difficult ethical challenges where standard clinical and economic outcomes used in cost-effectiveness analysis may be in conflict with social values. The authors propose why they think the evaluative framework of the capability approach may be advantageous in such areas, using non-invasive prenatal testing (NIPT), a screening test that analyses cell-free fetal DNA circulating in maternal blood in order to gain information about the fetal genotype, as a case study. The authors propose that adopting a capability evaluative framework in NIPT may account for the enhancement of valuable options available to prospective parents and families, as well as capabilities that may be diminished if NIPT was made routinely available, such as the option of refusing a test as an informed choice. A secondary analysis of qualitative data was conducted on women with experience of NIPT in Canada. Using a constructivist orientation to directed qualitative content analysis, interviews were analysed to see how NIPT related to a pre-existing list of ten Central Human Capabilities developed by philosopher Martha Nussbaum. From the analysis, they found eight of the ten Nussbaum capabilities emerge from the interviewees who were not directly asked to consider capability in the interview. As well as these eight (life; bodily health; bodily integrity; senses, imagination and thought; emotions; practical reason; affiliation; control over one’s environment), a new capability emerged related to care-taking as a result of NIPT, both for potential children and also the impact on existing children. The next challenge for the authors will be trying to formulate their findings into a usable outcome measure for decision-making. However, the analysis undertaken here is a good example of how economists can attempt to tackle the assessment of ethically challenging technologies as a way of dealing with standard economic outcomes that might be considered counter-productive in such evaluations.

Quality of life in a broader perspective: does ASCOT reflect the capability approach? Quality of Life Research [PubMedPublished 14th December 2017

The Adult Social Care Outcomes Toolkit (ASCOT) is a measure developed specifically for the economic assessment of social care interventions in the UK. Although a number of versions of ASCOT have been developed, the most recent version of ASCOT has been argued to be a measure influenced by the capability approach, even though previous versions of the measure were not justified similarly, so it remains to be seen how influential the capability approach is in the composition of this outcome measure. This study attempts to add justification of linking the capability approach with the ASCOT by conducting a literature review on the capability approach to identify key issues of quality of life measurement and how ASCOT deals with these issues. The methods for conducting the literature review are not described in detail in this paper, but the authors state that three primary issues with quality of life measurement in the capability approach literature that emerge from their review are concerned with 1. the measurement of capability, 2. non-reliance on adaptive preferences, and 3. focus on a multidimensional evaluative space. The authors argue that capability measurement is tackled by ASCOT, through the use of “as I want” phraseology at the top level on the ASCOT dimensions. Adaptive preferences are argued to be tackled by the use of general population preferences of different states on ASCOT and the outcome addresses several dimensions of quality of life. I would argue that there is much more to measuring capability beyond these three areas identified by the authors. Although the authors rightly question if the “as I want” phraseology is adequate to measure capability in their conclusion, the other two criteria could equally justify most measures for generating QALYs, so the criteria they use to be a capability measure is set at a very low benchmark. I remain unconvinced about how much of a capability measure ASCOT actually is in practice.

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Paul Mitchell’s journal round-up for 6th November 2017

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

A longitudinal study to assess the frequency and cost of antivascular endothelial therapy, and inequalities in access, in England between 2005 and 2015. BMJ Open [PubMed] Published 22nd October 2017

I am breaking one of my unwritten rules in a journal paper round-up by talking about colleagues’ work, but I feel it is too important not to provide a summary for a number of reasons. The study highlights the problems faced by regional healthcare purchasers in England when implementing national guideline recommendations on the cost-effectiveness of new treatments. The paper focuses on anti-vascular endothelial growth factor (anti-VEGF) medicines in particular, with two drugs, ranibizumab and aflibercept, offered to patients with a range of eye conditions, costing £550-800 per injection. Another drug, bevacizumab, that is closely related to ranibizumab and performs similarly in trials, could be provided at a fraction of the cost (£50-100 per injection), but it is currently unlicensed for eye conditions in the UK. This study investigates how the regional areas in England have coped with trying to provide the recommended drugs using administrative data from Hospital Episode Statistics in England between 2005-2015 by tracking their use since they have been recommended for a number of different eye conditions over the past decade. In 2014/15 the cost of these two new drugs for treating eye conditions alone was estimated at £447 million nationally. The distribution of where these drugs are provided is not equal, varying widely across regions after controlling for socio-demographics, suggesting an inequality of access associated with the introduction of these high-cost drugs over the past decade at a time of relatively low growth in national health spending. Although there are limitations associated with using data not intended for research purposes, the study shows how the most can be made from data routinely collected for non-research purposes. On a public policy level, it raises questions over the provision of such high-cost drugs, for which the authors state the NHS are currently paying more for than US insurers. Although it is important to be careful when comparing to unlicensed drugs, the authors point to clear evidence in the paper as to why their comparison is a reasonable one in this scenario, with a large opportunity cost associated with not including this option in national guidelines. If national recommendations continue to insist that such drugs be provided, clearer guidance is also required on how to disinvest from existing services at a regional level to reduce further examples of inequality in access in the future.

In search of a common currency: a comparison of seven EQ-5D-5L value sets. Health Economics [PubMed] Published 24th October 2017

For those of us out there who like a good valuation study, you will need to set yourself aside a good piece of time to work your way through this one. The new EQ-5D-5L measure of health status, with a primary purpose of generating quality-adjusted life years (QALYs) for economic evaluations, is now starting to have valuation studies emerging from different countries, whereby the relative importance of each of the measure dimensions and levels are quantified based on general population preferences. This study offers the first comparison of value sets across seven countries: 3 Western European (England, Netherlands, Spain), 1 North American (Canada), 1 South American (Uruguay), and two East Asian (Japan and South Korea). The authors in this paper aim to describe methodological differences between the seven value sets, compare the relative importance of dimensions, level decrements and scale length (i.e. quality/quantity trade-offs for QALYs), as well as developing a common (Western) currency across four of the value sets. In brief summary, there does appear to be similar trends across the three Western European countries: level decrements from levels 3 to 4 have the largest value, followed by levels 1 to 2. There is also a pattern in these three countries’ dimensions, whereby the two “symptom” dimensions (i.e. pain/discomfort, anxiety/depression) have equal importance to the other three “functioning” dimensions (i.e. mobility, self-care and usual activities). There are also clear differences with the other four value sets. Canada, although it also has the highest level decrements between levels 3 and 4 (49%), unusually has equal decrements for the remainder (17% x 3). For the other three countries, greater weight is attached to the three functioning dimensions relative to the two symptom dimensions. Although South Korea also has the greatest level decrements between level 3 and 4, it was greatest between level 4 and level 5 in Uruguay and levels 1 and 2 in Japan. Although the authors give a number of plausible reasons as to why these differences may occur, less justification is given in the choice of the four value sets they offer as a common currency, beyond the need to have a value set for countries that do not have one already. The most in-common value sets were the three Western European countries, so a Western European value set may have been more appropriate if the criterion was to have comparable values across countries. If the aim was really for a more international common currency, there are issues with the exclusion of non-Western countries’ value sets from their common currency version. Surely differences across cultures should be reflected in a common currency if they are apparent in different cultures and settings. A common currency should also have a better spread of regions geographically, with no country from Africa, the Middle East, Central and South Asia represented in this study, as well as no lower- and middle-income countries. Though this final criticism is out of the control of the authors based on current data availability.

Quantifying the relationship between capability and health in older people: can’t map, won’t map. Medical Decision Making [PubMed] Published 23rd October 2017

The EQ-5D is one of many ways quality of life can be measured within economic evaluations. A more recent way based on Amartya Sen’s capability approach has attempted to develop outcome measures that move beyond health-related aspects of quality of life captured by EQ-5D and similar measures used in the generation of QALYs. This study examines the relationship between the EQ-5D and the ICECAP-O capability measure in three different patient populations included in the Medical Crises in Older People programme in England. The authors propose a reasonable hypothesis that health could be considered a conversion factor for a person’s broader capability set, and so it is plausible to test how well the EQ-5D-3L dimension values and overall score can map onto the ICECAP-O overall score. Through numerous regressions performed, the strongest relationship between the two measures in this sample was an R-squared of 0.35. Interestingly, the dimensions on the EQ-5D that had a significant relationship with the ICECAP-O score were a mix of dimensions with a focus on functioning (i.e. self-care, usual activities) and symptoms (anxiety/depression), so overall capability on ICECAP-O appears to be related, at least to a small degree, to both health components of EQ-5D discussed in this round-up’s previous paper. The authors suggest it provides further evidence of the complementary data provided by EQ-5D and ICECAP-O, but the causal relationship, as the authors suggest, between both measures remains under-researched. Longitudinal data analysis would provide a more definitive answer to the question of how much interaction there is between these two measures and their dimensions as health and capability changes over time in response to different treatments and care provision.

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