Chris Sampson’s journal round-up for 2nd December 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.

The treatment decision under uncertainty: the effects of health, wealth and the probability of death. Journal of Health Economics Published 16th November 2019

It’s important to understand how people make decisions about treatment. At the end of life, the question can become a matter of whether to have treatment or to let things take their course such that you end up dead. In order to consider this scenario, the author of this paper introduces the probability of death to some existing theoretical models of decision-making under uncertainty.

The diagnostic risk model and the therapeutic risk model can be used to identify risk thresholds that determine decisions about treatment. The diagnostic model relates to the probability that disease is present and the therapeutic model relates to the probability that treatment is successful. The new model described in this paper builds on these models to consider the impact on the decision thresholds of i) initial health state, ii) probability of death, and iii) wealth. The model includes wealth after death, in the form of a bequest. Limited versions of the model are also considered, excluding the bequest and excluding wealth (described as a ‘QALY model’). Both an individual perspective and an aggregate perspective are considered by excluding and including the monetary cost of diagnosis and treatment, to allow for a social insurance type setting.

The comparative statics show a lot of ambiguity, but there are a few things that the model can tell us. The author identifies treatment as having an ‘insurance effect’, by reducing diagnostic risk, a ‘protective effect’, by lowering the probability of death, and a risk-increasing effect associated with therapeutic risk. A higher probability of death increases the propensity for treatment in both the no-bequest model and the QALY model, because of the protective effect of treatment. In the bequest model, the impact is ambiguous, because treatment costs reduce the bequest. In the full model, wealthier individuals will choose to undergo treatment at a lower probability of success because of a higher marginal utility for survival, but the effect becomes ambiguous if the marginal utility of wealth depends on health (which it obviously does).

I am no theoretician, so it can take me a long time to figure these things out in my head. For now, I’m not convinced that it is meaningful to consider death in this way using a one-period life model. In my view, the very definition of death is a loss of time, which plays little or no part in this model. But I think my main bugbear is the idea that anybody’s decision about life saving treatment is partly determined by the amount of money they will leave behind. I find this hard to believe. The author links the finding that a higher probability of death increases treatment propensity to NICE’s end of life premium. Though I’m not convinced that the model has anything to do with NICE’s reasoning on this matter.

Moving toward evidence-based policy: the value of randomization for program and policy implementation. JAMA [PubMed] Published 15th November 2019

Evidence-based policy is a nice idea. We should figure out whether something works before rolling it out. But decision-makers (especially politicians) tend not to think in this way, because doing something is usually seen to be better than doing nothing. The authors of this paper argue that randomisation is the key to understanding whether a particular policy creates value.

Without evidence based on random allocation, it’s difficult to know whether a policy works. This, the authors argue, can undermine the success of effective interventions and allow harmful policies to persist. A variety of positive examples are provided from US healthcare, including trials of Medicare bundled payments. Apparently, such trials increased confidence in the programmes’ effects in a way that post hoc evaluations cannot, though no evidence of this increased confidence is actually provided. Policy evaluation is not always easy, so the authors describe four preconditions for the success of such studies: i) early engagement with policymakers, ii) willingness from policy leaders to support randomisation, iii) timing the evaluation in line with policymakers’ objectives, and iv) designing the evaluation in line with the realities of policy implementation.

These are sensible suggestions, but it is not clear why the authors focus on randomisation. The paper doesn’t do what it says on the tin, i.e. describe the value of randomisation. Rather, it explains the value of pre-specified policy evaluations. Randomisation may or may not deserve special treatment compared with other analytical tools, but this paper provides no explanation for why it should. The authors also suggest that people are becoming more comfortable with randomisation, as large companies employ experimental methods, particularly on the Internet with A/B testing. I think this perception is way off and that most people feel creeped out knowing that the likes of Facebook are experimenting on them without any informed consent. In the authors’ view, it being possible to randomise is a sufficient basis on which to randomise. But, considering the ethics, as well as possible methodological contraindications, it isn’t clear that randomisation should become the default.

A new tool for creating personal and social EQ-5D-5L value sets, including valuing ‘dead’. Social Science & Medicine Published 30th November 2019

Nobody can agree on the best methods for health state valuation. Or, at least, some people have disagreed loud enough to make it seem that way. Novel approaches to health state valuation are therefore welcome. Even more welcome is the development and testing of methods that you can try at home.

This paper describes the PAPRIKA method (Potentially All Pairwise RanKings of all possible Alternatives) of discrete choice experiment, implemented using 1000Minds software. Participants are presented with two health states that are defined in terms of just two dimensions, each lasting for 10 years, and asked to choose between them. Using the magical power of computers, an adaptive process identifies further choices, automatically ranking states using transitivity so that people don’t need to complete unnecessary tasks. In order to identify where ‘dead’ sits on the scale, a binary search procedure asks participants to compare EQ-5D states with being dead. What’s especially cool about this process is that everybody who completes it is able to view their own personal value set. These personal value sets can then be averaged to identify a social value set.

The authors used their tool to develop an EQ-5D-5L value set for New Zealand (which is where the researchers are based). They recruited 5,112 people in an online panel, such that the sample was representative of the general public. Participants answered 20 DCE questions each, on average, and almost half of them said that they found the questions difficult to answer. The NZ value set showed that anxiety/depression was associated with the greatest disutility, though each dimension has a notably similar level of impact at each level. The value set correlates well with numerous existing value sets.

The main limitation of this research seems to be that only levels 1, 3, and 5 of each EQ-5D-5L domain were included. Including levels 2 and 4 would more than double the number of questions that would need to be answered. It is also concerning that more than half of the sample was excluded due to low data quality. But the authors do a pretty good job of convincing us that this is for the best. Adaptive designs of this kind could be the future of health state valuation, especially if they can be implemented online, at low cost. I expect we’ll be seeing plenty more from PAPRIKA.

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

A conceptual map of health-related quality of life dimensions: key lessons for a new instrument. Quality of Life Research [PubMed] Published 1st November 2019

EQ-5D, SF-6D, HUI3, AQoL, 15D; they’re all used to describe health states for the purpose of estimating health state utility values, to get the ‘Q’ in the QALY. But it’s widely recognised (and evidenced) that they measure different things. This study sought to better understand the challenge by doing two things: i) ‘mapping’ the domains of the different instruments and ii) advising on the domains to be included in a new measure.

The conceptual model described in this paper builds on two standard models of health – the ICF (International Classification of Functioning, Disability, and Health), which is endorsed by the WHO, and the Wilson and Cleary model. The new model is built around four distinctions, which can be used to define the dimensions included in health state utility instruments: cause vs effect, specific vs broad, physical vs psychological, and subjective vs objective. The idea is that each possible dimension of health can relate, with varying levels of precision, to one or the other of these alternatives.

The authors argue that, conveniently, cause/effect and specific/broad map to one another, as do physical/psychological and objective/subjective. The framework is presented visually, which makes it easy to interpret – I recommend you take a look. Each of the five instruments previously mentioned is mapped to the framework, with the HUI and 15D coming out as ‘symptom’ oriented, EQ-5D and SF-6D as ‘functioning’ oriented, and the AQoL as a hybrid of a health and well-being instrument. Based (it seems) on the Personal Wellbeing Index, the authors also include two social dimensions in the framework, which interact with the health domains. Based on the frequency with which dimensions are included in existing instruments, the authors recommend that a new measure should include three physical dimensions (mobility, self-care, pain), three mental health dimensions (depression, vitality, sleep), and two social domains (personal relationships, social isolation).

This framework makes no sense to me. The main problem is that none of the four distinctions hold water, let alone stand up to being mapped linearly to one another. Take pain as an example. It could be measured subjectively or objectively. It’s usually considered a physical matter, but psychological pain is no less meaningful. It may be a ‘causal’ symptom, but there is little doubt that it matters in and of itself as an ‘effect’. The authors themselves even offer up a series of examples of where the distinctions fall down.

It would be nice if this stuff could be drawn-up on a two-dimensional plane, but it isn’t that simple. In addition to oversimplifying complex ideas, I don’t think the authors have fully recognised the level of complexity. For instance, the work seems to be inspired – at least in part – by a desire to describe health state utility instruments in relation to subjective well-being (SWB). But the distinction between health state utility instruments and SWB isn’t simply a matter of scope. Health state utility instruments (as we use them) are about valuing states in relation to preferences, whereas SWB is about experienced utility. That’s a far more important and meaningful distinction than the distinction between symptoms and functioning.

Careless costs related to inefficient technology used within NHS England. Clinical Medicine Journal [PubMed] Published 8th November 2019

This little paper – barely even a single page – was doing the rounds on Twitter. The author was inspired by some frustration in his day job, waiting for the IT to work. We can all relate to that. This brief analysis sums the potential costs of what the author calls ‘careless costs’, which is vaguely defined as time spent by an NHS employee on activity that does not relate to patient care. Supposing that all doctors in the English NHS wasted an average of 10 minutes per day on such activities, it would cost over £143 million (per year, I assume) based on current salaries. The implication is that a little bit of investment could result in massive savings.

This really bugs me, for at least two reasons. First, it is normal for anybody in any profession to have a bit of downtime. Nobody operates at maximum productivity for every minute of every day. If the doctor didn’t have their downtime waiting for a PC to boot, it would be spent queuing in Costa, or having a nice relaxed wee. Probably both. Those 10 minutes that are displaced cannot be considered equivalent in value to 10 minutes of patient contact time. The second reason is that there is no intervention that can fix this problem at little or no cost. Investments cost money. And if perfect IT systems existed, we wouldn’t all find these ‘careless costs’ so familiar. No doubt, the NHS lags behind, but the potential savings of improvement may very well be closer to zero than to the estimates in this paper.

When it comes to clinical impacts, people insist on being able to identify causal improvements from clearly defined interventions or changes. But when it comes to costs, too many people are confident in throwing around huge numbers of speculative origin.

Socioeconomic disparities in unmet need for student mental health services in higher education. Applied Health Economics and Health Policy [PubMed] Published 5th November 2019

In many countries, the size of the student population is growing, and this population seems to have a high level of need for mental health services. There are a variety of challenges in this context that make it an interesting subject for health economists to study (which is why I do), including the fact that universities are often the main providers of services. If universities are going to provide the right services and reach the right people, a better understanding of who needs what is required. This study contributes to this challenge.

The study is set in the context of higher education in Ireland. If you have no idea how higher education is organised in Ireland, and have an interest in mental health, then the Institutional Context section of this paper is worth reading in its own right. The study reports on findings from a national survey of students. This analysis is a secondary analysis of data collected for the primary purpose of eliciting students’ preferences for counselling services, which has been described elsewhere. In this paper, the authors report on supplementary questions, including measures of psychological distress and use of mental health services. Responses from 5,031 individuals, broadly representative of the population, were analysed.

Around 23% of respondents were classified as having unmet need for mental health services based on them reporting both a) severe distress and b) not using services. Arguably, it’s a sketchy definition of unmet need, but it seems reasonable for the purpose of this analysis. The authors regress this binary indicator of unmet need on a selection of sociodemographic and individual characteristics. The model is also run for the binary indicator of need only (rather than unmet need).

The main finding is that people from lower social classes are more likely to have unmet need, but that this is only because these people have a higher level of need. That is, people from less well-off backgrounds are more likely to have mental health problems but are no less likely to have their need met. So this is partly good news and partly bad news. It seems that there are no additional barriers to services in Ireland for students from a lower social class. But unmet need is still high and – with more inclusive university admissions – likely to grow. Based on the analyses, the authors recommend that universities could reach out to male students, who have greater unmet need.

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Chris Sampson’s journal round-up for 5th August 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.

The barriers and facilitators to model replication within health economics. Value in Health Published 16th July 2019

Replication is a valuable part of the scientific process, especially if there are uncertainties about the validity of research methods. When it comes to cost-effectiveness modelling, there are endless opportunities for researchers to do things badly, even with the best intentions. Attempting to replicate modelling studies can therefore support health care decision-making. But replication studies are rarely conducted, or, at least, rarely reported. The authors of this study sought to understand the factors that can make replication easy or difficult, with a view to informing reporting standards.

The authors attempted to replicate five published cost-effectiveness modelling studies, with the aim of recreating the key results. Each replication attempt was conducted by a different author and we’re even given a rating of the replicator’s experience level. The characteristics of the models were recorded and each replicator detailed – anecdotally – the things that helped or hindered their attempt. Some replications were a resounding failure. In one case, the replicated cost per patient was more than double the original, at more than £1,000 wide of the mark. Replicators reported that having a clear diagram of the model structure was a big help, as was the provision of example calculations and explicit listing of the key assumptions. Various shortcomings made replication difficult, all relating to a lack of clarity or completeness in reporting. The impact of this on the validation attempt was exacerbated if the model either involved lots of scenarios that weren’t clearly described or if the model had a long time horizon.

The quality of each study was assessed using the Philips checklist, and all did pretty well, suggesting that the checklist is not sufficient for ensuring replicability. If you develop and report cost-effectiveness models, this paper could help you better understand how end-users will interpret your reporting and make your work more replicable. This study focusses on Markov models. They’re definitely the most common approach, so perhaps that’s OK. It might be useful to produce prescriptive guidance specific to Markov models, informed by the findings of this study.

US integrated delivery networks perspective on economic burden of patients with treatment-resistant depression: a retrospective matched-cohort study. PharmacoEconomics – Open [PubMed] Published 28th June 2019

Treatment-resistant depression can be associated high health care costs, as multiple lines of treatment are tried, with patients experiencing little or no benefit. New treatments and models of care can go some way to addressing these challenges. In the US, there’s some reason to believe that integrated delivery networks (IDNs) could be associated with lower care costs, because IDNs are based on collaborative care models and constitute a single point of accountability for patient costs. They might be particularly useful in the case of treatment-resistant depression, but evidence is lacking. The authors of this study investigated the difference in health care resource use and costs for patients with and without treatment-resistant depression, in the context of IDNs.

The researchers conducted a retrospective cohort study using claims data for people receiving care from IDNs, with up to two years follow-up from first antidepressant use. 1,582 people with treatment-resistant depression were propensity score matched to two other groups – patients without depression and patients with depression that was not classified as treatment-resistant. Various regression models were used to compare the key outcomes of all-cause and specific categories of resource use and costs. Unfortunately, there is no assessment of whether the selected models are actually any good at estimating differences in costs.

The average costs and resource use levels in the three groups ranked as you would expect: $25,807 per person per year for the treatment-resistant group versus $13,701 in the non-resistant group and $8,500 in the non-depression group. People with treatment-resistant depression used a wider range of antidepressants and for a longer duration. They also had twice as many inpatient visits as people with depression that wasn’t treatment-resistant, which seems to have been the main driver of the adjusted differences in costs.

We don’t know (from this study) whether or not IDNs provide a higher quality of care. And the study isn’t able to compare IDN and non-IDN models of care. But it does show that IDNs probably aren’t a full solution to the high costs of treatment-resistant depression.

Rabin’s paradox for health outcomes. Health Economics [PubMed] [RePEc] Published 19th June 2019

Rabin’s paradox arises from the theoretical demonstration that a risk-averse individual who turns down a 50:50 gamble of gaining £110 or losing £100 would, if expected utility theory is correct, turn down a 50:50 gamble of losing £1,000 or gaining millions. This is because of the assumed concave utility function over wealth that is used to model risk aversion and it is probably not realistic. But we don’t know about the relevance of this paradox in the health domain… until now.

A key contribution of this paper is that it considers both decision-making about one’s own health and decision-making from a societal perspective. Three different scenarios are set-up in each case, relating to gains and losses in life expectancy with different levels of health functioning. 201 students were recruited as part of a larger study on preferences and each completed all six gamble-pairs (three individual, three societal). To test for Rabin’s paradox, the participants were asked whether they would accept each gamble involving a moderate stake and a large stake.

In short, the authors observe Rabin’s proposed failure of expected utility theory. Many participants rejected small gambles but did not reject the larger gambles. The effect was more pronounced for societal preferences. Though there was a large minority for whom expected utility theory was not violated. The upshot of all this is that our models of health preferences that are based on expected utility may be flawed where uncertain outcomes are involved – as they often are in health. This study adds to a growing body of literature supporting the relevance of alternative utility theories, such as prospect theory, to health and health care.

My only problem here is that life expectancy is not health. Life expectancy is everything. It incorporates the monetary domain, which this study did not want to consider, as well as every other domain of life. When you die, your stock of cash is as useful to you as your stock of health. I think it would have been more useful if the study focussed only on health status and outcomes and excluded all considerations of death.

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