Chris Sampson’s journal round-up for 18th February 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.

An educational review about using cost data for the purpose of cost-effectiveness analysis. PharmacoEconomics [PubMed] Published 12th February 2019

Costing can seem like a cinderella method in the health economist’s toolkit. If you’re working on an economic evaluation, estimating resource use and costs can be tedious. That is perhaps why costing methodology has been relatively neglected in the literature compared to health state valuation (for example). This paper tries to redress the balance slightly by providing an overview of the main issues in costing, explaining why they’re important, so that we can do a better job. The issues are more complex than many assume.

Supported by a formidable reference list (n=120), the authors tackle 9 issues relating to costing: i) costs vs resource use; ii) trial-based vs model-based evaluations; iii) costing perspectives; iv) data sources; v) statistical methods; vi) baseline adjustments; vii) missing data; viii) uncertainty; and ix) discounting, inflation, and currency. It’s a big paper with a lot to say, so it isn’t easily summarised. Its role is as a reference point for us to turn to when we need it. There’s a stack of papers and other resources cited in here that I wasn’t aware of. The paper itself doesn’t get technical, leaving that to the papers cited therein. But the authors provide a good discussion of the questions that ought to be addressed by somebody designing a study, relating to data collection and analysis.

The paper closes with some recommendations. The main one is that people conducting cost-effectiveness analysis should think harder about why they’re making particular methodological choices. The point is also made that new developments could change the way we collect and analyse cost data. For example, the growing use of observational data demands that greater consideration be given to unobserved confounding. Costing methods are important and interesting!

A flexible open-source decision model for value assessment of biologic treatment for rheumatoid arthritis. PharmacoEconomics [PubMed] Published 9th February 2019

Wherever feasible, decision models should be published open-source, so that they can be reviewed, reused, recycled, or, perhaps, rejected. But open-source models are still a rare sight. Here, we have one for rheumatoid arthritis. But the paper isn’t really about the model. After all, the model and supporting documentation are already available online. Rather, the paper describes the reasoning behind publishing a model open-source, and the process for doing so in this case.

This is the first model released as part of the Open Source Value Project, which tries to convince decision-makers that cost-effectiveness models are worth paying attention to. That is, it’s aimed at the US market, where models are largely ignored. The authors argue that models need to be flexible to be valuable into the future and that, to achieve this, four steps should be followed in the development: 1) release the initial model, 2) invite feedback, 3) convene an expert panel to determine actions in light of the feedback, and 4) revise the model. Then, repeat as necessary. Alongside this, people with the requisite technical skills (i.e. knowing how to use R, C++, and GitHub) can proffer changes to the model whenever they like. This paper was written after step 3 had been completed, and the authors report receiving 159 comments on their model.

The model itself (which you can have a play with here) is an individual patient simulation, which is set-up to evaluate a variety of treatment scenarios. It estimates costs and (mapped) QALYs and can be used to conduct cost-effectiveness analysis or multi-criteria decision analysis. The model was designed to be able to run 32 different model structures based on different assumptions about treatment pathways and outcomes, meaning that the authors could evaluate structural uncertainties (which is a rare feat). A variety of approaches were used to validate the model.

The authors identify several challenges that they experienced in the process, including difficulties in communication between stakeholders and the large amount of time needed to develop, test, and describe a model of this sophistication. I would imagine that, compared with most decision models, the amount of work underlying this paper is staggering. Whether or not that work is worthwhile depends on whether researchers and policymakers make us of the model. The authors have made it as easy as possible for stakeholders to engage with and build on their work, so they should be hopeful that it will bear fruit.

EQ-5D-Y-5L: developing a revised EQ-5D-Y with increased response categories. Quality of Life Research [PubMed] Published 9th February 2019

The EQ-5D-Y has been a slow burner. It’s been around 10 years since it first came on the scene, but we’ve been without a value set and – with the introduction of the EQ-5D-5L – the questionnaire has lost some comparability with its adult equivalent. But the EQ-5D-Y has almost caught-up, and this study describes part of how that’s been achieved.

The reason to develop a 5L version for the EQ-5D-Y is the same as for the adult version – to reduce ceiling effects and improve sensitivity. A selection of possible descriptors was identified through a review of the literature. Focus groups were conducted with children between 8 and 15 years of age in Germany, Spain, Sweden, and the UK in order to identify labels that can be understood by young people. Specifically, the researchers wanted to know the words used by children and adolescents to describe the quantity or intensity of health problems. Participants ranked the labels according to severity and specified which labels they didn’t like. Transcripts were analysed using thematic content analysis. Next, individual interviews were conducted with 255 participants across the four countries, which involved sorting and response scaling tasks. Younger children used a smiley scale. At this stage, both 4L and 5L versions were being considered. In a second phase of the research, cognitive interviews were used to test for comprehensibility and feasibility.

A 5-level version was preferred by most, and 5L labels were identified in each language. The English version used terms like ‘a little bit’, ‘a lot’, and ‘really’. There’s plenty more research to be done on the EQ-5D-Y-5L, including psychometric testing, but I’d expect it to be coming to studies near you very soon. One of the key takeaways from this study, and something that I’ve been seeing more in research in recent years, is that kids are smart. The authors make this point clear, particulary with respect to the response scaling tasks that were conducted with children as young as 8. Decision-making criteria and frameworks that relate to children should be based on children’s preferences and ideas.

Credits

Simon McNamara’s journal round-up for 21st January 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.

Assessing capability in economic evaluation: a life course approach? The European Journal of Health Economics [PubMed] Published 8th January 2019

If you have spent any time on social media in the last week there is a good chance that you will have seen the hashtag #10yearchallenge. This hashtag is typically accompanied by two photos of the poster; one recent, and one from 10 years ago. Whilst the minority of these posts suggest that the elixir of permanent youth has been discovered and is being hidden away by a select group of people, the majority show clear signs of ageing. As time passes, we change. Our skin becomes wrinkled, our hair may become grey, and we may become heavier. What these pictures don’t show, is how we change internally – and I don’t mean biologically. As we become older, and we experience life, so the things we think are important change. Our souls become wrinkled, and our minds become heavier.

The first paper in this week’s round-up is founded on this premise, albeit grounded in the measurement of capability well-being across the life course, rather than a hashtag. The capabilities approach is grounded in the normative judgement that the desirability of policy outcomes should be evaluated by what Sen called the ‘capabilities’ they provide – “the functionings, or the capabilities to function” they give people, where functionings for a person are defined as “the various things that he or she manages to do or be in leading a good life” (Sen, 1993). The author (Joanna Coast) appeals to her, and others’, work on the family of ICECAP measures (capability measures), in order to argue that the capabilities we value changes across the stage of life we are experiencing. For example, she notes that the development work for the ICECAP-A (adults) resulted in the choice of an ‘achievement’ attribute in that instrument, whilst for ICECAP-O (older people) an alternative ‘role’ attribute was used – with the achievement attribute primarily linked to having the ability to make progress in life, and the role attribute linked to having the ability to do things that make you feel valued. Similarly, she notes that the attributes that emerged from development work on the ICECAP-SCM (supportive care – a term for the end of life) are different to those from ICECAP-A (adults), with dignity coming to the forefront as a valued attribute towards the end of life. The author then goes on to suggest that it would be normatively desirable to capture how the capabilities we value changes over the life-course, suggests this could be done with a range of different measures, and highlights a number of problems associated with this (e.g. when does a life-stage start and finish?).

You should read this paper. It is only four pages long and definitely worth your time. If you have spent enough time on social media to know what the #10yearchallenge is, then you definitely have time to read it. I think this is a really interesting topic and a great paper. It has certainly got me thinking more about capabilities, and I will be keeping an eye out for future papers on this in future.

Future directions in valuing benefits for estimating QALYs: is time up for the EQ-5D? Value in Health Published 17th January 2019

If EQ-5D were a person, I think I would be giving it a good hug right now. Every time my turn to write this round-up comes up there seems to be a new article criticising it, pointing out potential flaws in the way it has been valued, or proposing a new alternative. If it could speak, I imagine it would tell us it is doing its best – perhaps with a small tear in its eye. It has done what it can to evolve, it has tried to change, but as we approach its 30th birthday, and exciting new instruments are under development, the authors of the second paper in this week’s round-up question – “Is time up for the EQ-5D?”

If you are interested in the valuation of outcomes, you should probably read this paper. It is a really neat summary of recent developments in the assessment and valuation of the benefits of healthcare, and gives a good indication of where the field may be headed. Before jumping into reading the paper, it is worth dwelling on its title. Note that the authors have used the term “valuing benefits for estimating QALYs” and not “valuing health states for estimating QALYs”. This is telling, and reflects the growing interest in measuring, and valuing, the benefits of healthcare based upon a broader conception of well-being, rather than simply health as represented by the EQ-5D. It is this issue that rests at the heart of the paper, and is probably the biggest threat to the long-term domination of EQ-5D. If it wasn’t designed to capture the things we are now interested in, then why not modify it further, or go back to the drawing board and start again?

I am not going to attempt to cover all the points made in the paper, as I can’t do it justice in this blog; but in summary, the authors review a number of ways this could be done, outline recent developments in the way the subsequent instrument could be valued, and detail the potential advantages, disadvantages, and challenges of moving to a new instrument. Ultimately, the authors conclude that the future of the valuation of outcomes – be that with EQ-5D or something else, depends upon a number of judgements, including whether non-health factors are considered to be relevant when valuing the benefits of healthcare. If they are then EQ-5D isn’t fit for purpose, and we need a new instrument. Whilst the paper doesn’t provide a definitive answer to the question “Is Time Up for the EQ-5D?”, the fact that NICE, the EuroQol group, two of the authors of this paper, and a whole host of others, are currently collaborating on a new measure, which captures both health and non-health outcomes, indicates that EQ-5D may well be nearing the end of its dominance. I look forward to seeing how this work progresses over the next few years.

The association between economic uncertainty and suicide in the short-run. Social Science and Medicine [PubMed] [RePEc] Published 24th November 2018

As I write this, the United Kingdom is 10 weeks away from the date we are due to leave the European Union, and we are still uncertain about how, and potentially even whether, we will finally leave. The uncertainty created by Brexit covers both economic and social spheres, and impacts many of those in the United Kingdom, and many beyond who have ties to us. I am afraid the next paper isn’t a cheery one, but given this situation, it is a timely one.

In the final paper in this round-up, the authors explore the link between economic uncertainty and short-term suicide rates. This is done by linking the UK EPU index of economic uncertainty – an index generated based upon the articles published in 650 UK newspapers – to the daily suicide rates in England and Wales between 2001 and 2015. The authors find evidence of an increase in suicide rates on the days on which the EPU index was higher, and also of a lagged effect on the day after a spike in the index. Over the course of a year, this effect means a one standard deviation increase in the EPU is expected to lead to 11 additional deaths in that year. In comparison to the number of deaths per year from cardiovascular disease, and cancer, this effect is relatively modest, but is nevertheless concerning given the nature of the way in which these people are dying.

I am not going to pretend I enjoyed reading this paper. Technically it is good, and it is an interesting paper, but the topic was just a bit too dark and too relevant to our current situation. Whilst reading I couldn’t help but wonder whether I am going to be reading a similar paper linking Brexit uncertainty to suicide at some point in the future. Fingers crossed this isn’t the case.

Credits

Chris Sampson’s journal round-up for 7th January 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.

Overview, update, and lessons learned from the international EQ-5D-5L valuation work: version 2 of the EQ-5D-5L valuation protocol. Value in Health Published 2nd January 2019

Insofar as there is any drama in health economics, the fallout from the EQ-5D-5L value set for England was pretty dramatic. If you ask me, the criticisms are entirely ill-conceived. Regardless of that, one of the main sticking points was that the version of the EQ-5D-5L valuation protocol that was used was flawed. England was one of the first countries to get a valuation, so it used version 1.0 of the EuroQol Valuation Technique (EQ-VT). We’re now up to version 2.1. This article outlines the issues that arose in using the first version, what EuroQol did to try and solve them, and describes the current challenges in valuation.

EQ-VT 1.0 includes the composite time trade-off (cTTO) task to elicit values for health states better and worse than dead. Early valuation studies showed some unusual patterns. Research into the causes of this showed that in many cases there was very little time spent on the task. Some interviewers had a tendency to skip parts of the explanation for completing the worse-than-dead bit of the cTTO, resulting in no values worse than dead. EQ-VT 1.1 added three practise valuations along with greater monitoring of interviewer performance and a quality control procedure. This dramatically reduced interviewer effects and the likelihood of inconsistent responses. Yet further improvements could be envisioned. And so EQ-VT 2.0 added a feedback module. The feedback module shows respondents the ranking of states implied by their valuations, with which respondents can then agree or disagree. 2.0 was tested against 1.1 and showed further reductions in inconsistencies thanks to the feedback module. Other modifications were not supported by the evaluation. EQ-VT 2.1 added a dynamic question to further improve the warm-up tasks.

There are ongoing challenges with the cTTO, mostly to do with how to model the data. The authors provide a table setting out causes, consequences, and possible solutions for various issues that might arise in the modelling of cTTO data. And then there’s the discrete choice experiment (DCE), which is included in addition to the cTTO, but which different valuation studies used (or did not use) differently in modelling values. Research is ongoing that will probably lead to developments beyond EQ-VT 2.1. This might involve abandoning the cTTO altogether. Or, at least, there might be a reduction in cTTO tasks and a greater reliance on DCE. But more research is needed before duration can be adequately incorporated into DCEs.

Helpfully, the paper includes a table with a list of countries and specification of the EQ-VT versions used. This demonstrates the vast amount of knowledge that has been accrued about EQ-5D-5L valuation and the lack of wisdom in continuing to support the (relatively under-interrogated) EQ-5D-3L MVH valuation.

Do time trade-off values fully capture attitudes that are relevant to health-related choices? The European Journal of Health Economics [PubMed] Published 31st December 2018

Different people have different preferences, so values for health states elicited using TTO should vary from person to person. This study is concerned with how personal circumstances and beliefs influence TTO values and whether TTO entirely captures the impact of these on preferences for health states.

The authors analysed data from an online survey with a UK-representative sample of 1,339. Participants were asked about their attitudes towards quality and quantity of life, before completing some TTO tasks based on the EQ-5D-5L. Based on their response, they were shown two ‘lives’ that – given their TTO response – they should have considered to be of equivalent value. The researchers constructed generalised estimating equations to model the TTO values and logit models for the subsequent choices between states. Age, marital status, education, and attitudes towards trading quality and quantity of life all determined TTO values in addition to the state that was being valued. In the modelling of the decisions about the two lives, attitudes influenced decisions through the difference between the two lives in the number of life years available. That is, an interaction term between the attitudes variable and years variables showed that people who prefer quantity of life over quality of life were more likely to choose the state with a greater number of years.

The authors’ interpretation from this is that TTO reflects people’s attitudes towards quality and quantity of life, but only partially. My interpretation would be that the TTO exercise would have benefitted from the kind of refinement described above. The choice between the two lives is similar to the feedback module of the EQ-VT 2.0. People often do not understand the implications of their TTO valuations. The study could also be interpreted as supportive of ‘head-to-head’ choice methods (such as DCE) rather than making choices involving full health and death. But the design of the TTO task used in this study was quite dissimilar to others, which makes it difficult to say anything generally about TTO as a valuation method.

Exploring the item sets of the Recovering Quality of Life (ReQoL) measures using factor analysis. Quality of Life Research [PubMed] Published 21st December 2018

The ReQoL is a patient-reported outcome measure for use with people experiencing mental health difficulties. The ReQoL-10 and ReQoL-20 both ask questions relating to seven domains: six mental, one physical. There’s been a steady stream of ReQoL research published in recent years and the measures have been shown to have acceptable psychometric properties. This study concerns the factorial structure of the ReQoL item sets, testing internal construct validity and informing scoring procedures. There’s also a more general methodological contribution relating to the use of positive and negative factors in mental health outcome questionnaires.

At the outset of this study, the ReQoL was based on 61 items. These were reduced to 40 on the basis of qualitative and quantitative analysis reported in other papers. This paper reports on two studies – the first group (n=2,262) completed the 61 items and the second group (n=4,266) completed 40 items. Confirmatory factor analysis and exploratory factor analysis were conducted. Six-factor (according to ReQoL domains), two-factor (negative/positive) and bi-factor (global/negative/positive) models were tested. In the second study, participants were either presented with a version that jumbled up the positively and negatively worded questions or a version that showed a block of negatives followed by a block of positives. The idea here is that if a two-factor structure is simply a product of the presentation of questions, it should be more pronounced in the jumbled version.

The results were much the same from the two study samples. The bi-factor model demonstrated acceptable fit, with much higher factor loadings on the general quality of life factor that loaded on all items. The results indicated sufficient unidimensionality to go ahead with reducing the number of items and the two ordering formats didn’t differ, suggesting that the negative and positive loadings weren’t just an artefact of the presentation. The findings show that the six dimensions of the ReQoL don’t stand as separate factors. The justification for maintaining items from each of the six dimensions, therefore, seems to be a qualitative one.

Some outcome measurement developers have argued that items should all be phrased in the same direction – as either positive or negative – to obtain high-quality data. But there’s good reason to think that features of mental health can’t reliably be translated from negative to positive, and this study supports the inclusion (and intermingling) of both within a measure.

Credits