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.

Credits

Chris Sampson’s journal round-up for 5th September 2016

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 effect of complementary private health insurance on the use of health care services. International Journal of Health Economics and Management Published 31st August 2016

Moral hazard is one of the key ideas taught to fledgling health economists, but having taken flight you don’t hear all that much about it. That’s because most of us live in Europe, enjoying our universal publicly funded health care systems. But I quite like papers that remind me that moral hazard is still a going concern and that my MSc was relevant. This paper looks at the impact of complementary private health insurance – that is, alongside a national health service. There aren’t so many studies of moral hazard in this setting. Private health insurance (let’s call it PHI) might decrease use of public health care (let’s call it NHS), but it might also increase pressure on the NHS by creating additional demand. For example, people might need a referral from an NHS GP in order to qualify for PHI coverage. This study uses cross-sectional questionnaire data from Denmark, collected from 5447 individuals for the purpose of this study. The questionnaire collected all sorts of data relating to health care use and sociodemographics. People who gave ‘Don’t know’ or ‘Other’ responses were dropped, meaning that only 4362 were analysed. 49% of the sample had PHI – the ‘treatment’ of interest. The authors use a bivariate probit model with propensity score matching to predict health care use. Furthermore, an instrumental variable is used to improve identification. Having PHI seems to increase use of services, with strong effects for prescription medicine, dentist visits and chiropractors. This suggests that PHI coverage may contribute to increasing national health care costs. There are some major limitations to this study, which the authors acknowledge. The response rate was 41%, and the sample wasn’t particularly representative. The one thing I can’t get my head around is the authors’ identification strategy. The instrumental variable chosen was whether or not an individual wears glasses, as in this case PHI is particularly favourable. Even controlling for the covariates used in this analysis, I cannot see (no pun intended) how this could be unrelated to health care use.

The value of disease prevention vs treatment. Journal of Health Economics Published 29th August 2016

The public’s view of pharma just keeps getting worse“, apparently. One probably-entirely-made-up-but-sort-of-reasonable-sounding thing I’ve heard Joe Public say in the past is that Pharma would like us all to remain sickly cash cows. New treatments = milk. Prevention is just… soya. That analogy made no sense, but there are also more reasoned arguments that we spend too much on treatment and too little on prevention. There are also numerous studies characterising people’s preferences regarding prevention and treatment under different conditions. This study builds on this background by developing a utility model of disease valuation in order to derive willingness-to-pay values for reductions in incidence (prevention), mortality (treatment) or deterioration in quality of life (palliative care). The basis for the model is 3 possible states – healthy, ill and dead – through which people can progress in only one direction (i.e. there is no cure). The ‘ill’ state relates to a specific disease and has a value somewhere between 1 (healthy) and 0 (dead). The authors use the model to determine – for example – how willingness to pay for improvement in the ‘ill’ state might be affected by the mortality rate. Two key implications of the model are that i) when the risk of dying from a disease is greater than the incidence rate, prevention is more valuable than treatment and ii) when the incidence rate is greater than the decline in quality of life, prevention is more valuable than palliative care. The model is also used to incorporate probability weighting to give a more realistic characterisation of people’s risk preferences. In most cases, the two previous findings will hold. An interesting finding of this part of the analysis is that it seems to partly explain people’s disproportionately strong preferences for treating more severe diseases. The model suggests that prevention is more valuable than treatment for most real-world situations, and so we’ve probably got the balance all wrong.

Does one size fit all? Assessing the preferences of older and younger people for attributes of quality of life. Quality of Life Research [PubMed] Published 23rd August 2016

There’s plenty of talk nowadays about the idea that QALYs don’t reflect the most important objects of value for particular groups of people, especially older people. Non-health improvements in quality of life might be more important. Whether we’re using EQ-5D, SF-6D, HUI3 or your personally preferred multi-attribute utility measure, the idea is that they’re measuring the same thing. But they’re not. They consistently give systematically different results. This study sought to find out if older people value quality of life attributes used in these measures differently to younger people. The authors elicit preferences for different domains using a web-based survey of two groups of 500 people: over 65s and 18-64 year olds. Individuals were presented with 12 descriptors from the EQ-5D, AQoL and ASCOT and asked to complete both a ranking and a best worst exercise. Socioeconomic data were also collected. The two cohorts ranked the domains differently, but perhaps not as differently as we might expect. ‘Independence’ was important to both groups, with 36% of over 65s and 20% of 18-64 year olds ranking it first. Physical mobility, mental health and pain also ranked highly for both groups. Older people ranked control, self-care and vision more highly than younger people, who in turn ranked safety, social relationships, dignity, sleep and hearing more highly. The results from the ranking exercise and the best worst exercise were similar. So, non-health attributes matter to everyone and older people’s preferences differ to younger people’s. But so what? We could probably find differences between a sample of men and a sample of women, or between an urban and a rural population. The question is: which differences matter? Studies like this are useful, but they can’t tell us how we ought to handle heterogeneous preferences.

From representing views to representativeness of views: Illustrating a new (Q2S) approach in the context of health care priority setting in nine European countries. Social Science & Medicine [PubMedPublished 22nd August 2016

Asking the public what they think; it’s a dangerous game (nb Brexit, Boaty McBoatface, Mrs Brown’s Boys). But there are good grounds for doing so when it comes to health care resource allocation. This paper comes from an ongoing research project that I’ve written about on a couple of occasions. A previous paper used Q methodology and identified 5 viewpoints regarding the fundamental basis for the allocation of resources in health care, titled: 1) ‘egalitarianism, entitlement and equality of access’, 2) ‘severity and the magnitude of health gains’, 3) ‘fair innings, young people and maximising health benefits’, 4) ‘the intrinsic value of life and healthy living’ and 5) ‘quality life is more important than simply staying alive’. This study developed a new methodology called Q2S, designed to extract features from the viewpoints elicited through the original Q study and create a survey to find out how these different viewpoints are represented in society. Data were collected from 39,560 respondents from 9 European countries. Participants were presented with a series of descriptions with which to identify agreement on a 7-point Likert scale from “very unlike my point of view” to “very much like my point of view”. 41% of respondents gave their highest score to a single viewpoint, while the rest tied across two or more viewpoints and were subsequently asked to identify which one would best reflect their view. 43% of respondents were allocated to Viewpoint 1. This viewpoint asserts that health care is a basic right, that treatment effectiveness is essentially irrelevant because all life has the same value, and that scarcity is not a concern. It was predominant in all 9 countries. Gulp! Next up with 17% was Viewpoint 2, which is a bit closer to health maximisation but with a preference for allocation to life-saving treatment and more severe health states. Viewpoint 3 was not popular, with only 4% of people identifying it as most like their point of view. The authors identify various associations between sociodemographic variables and likelihood of particular viewpoints. There’s a lot of food for thought in this paper. Where do you sit? My position changes depending on how revolutionary I’m feeling.

Photo credit: Antony Theobald (CC BY-NC-ND 2.0)

Chris Sampson’s journal round-up for 16th May 2016

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.

Higher mortality rates amongst emergency patients admitted to hospital at weekends reflect a lower probability of admission. Journal of Health Services Research & Policy Published 6th May 2016

The ‘weekend effect‘ is the hot topic in health policy in the UK right now. Whether or not it exists, and whether or not it can be corrected by steamrollering junior doctors’ contracts, has major implications for the NHS. In this study the authors used data on 12.7 million A&E attendances and 4.7 million emergency admissions in England in 2013-14. It’s possible to be admitted to hospital via A&E or directly from a community service. A&E is available 24/7, while community services are more limited at the weekend. The analyses mainly use logistic regressions with the usual case-mix adjustments to estimate the probability of death within 30 days. Weekend attendance at A&E was not associated with a significantly higher probability of death than attendance during the week. On Saturday or Sunday, there were 7% fewer admissions via A&E than on weekdays. The number of direct admissions via referral from community services was a whopping 61% lower at weekends. For both groups of people admitted, the mortality rate at the weekend was higher than on weekdays; we see the familiar weekend effect. The 7% difference in A&E admission rates could not be explained by the patient characteristics available in the data, suggesting that a higher admission threshold is used at weekends. There was no weekend effect associated with A&E attendances, which is perhaps what a lot of people have in mind when they think about this issue. Only those admitted at the weekend have a higher mortality rate, and in particular those referred from community services. The implication is that mortality rates hide the true story by combining the number of people dying (the numerator) with the number of people being admitted (the denominator). Increasing the number of doctors available at weekends might increase the number of people being admitted (at great cost) but with no reduction in the number of deaths. Patients who are admitted to hospital at the weekend are a different group of people, and different in a way that has not yet been adequately captured by risk-adjustment.

Ageing, justice and resource allocation. Journal of Medical Ethics [PhilPapers] [PubMedPublished 4th May 2016

People are living longer. This contributes to health care expenditure growth as people require more treatment to keep them alive. In this paper, the author argues that we should not focus only on the role of life-prolonging treatments but also on life-enhancing treatments. How people age and the ways in which the chances of becoming ill vary with age ought to be considered in resource allocation decisions. Social context is important in this respect; for example, the availability of public toilets may influence an older person’s willingness to engage in their usual activities. The arguments presented focus mainly on Norman Daniels’s prudential lifespan approach, which essentially considers whether or not a person would choose to purchase insurance for a particular health problem. We would expect an ageing population to insure more against the health problems of later life, and so proportionally greater resources ought to be allocated to older people. But the paper does not pursuade me that this requires any departure from current practice or thought. When Alan Williams described the fair innings approach to just allocations of resources in old age, he was expressly concerned with the quality of life. I’m not clear on what this paper adds, aside from further criticism of Harris’s view that life-extending treatment should always trump life-enhancing treatment. But I know of nobody who actually supports that view. Nevertheless, it’s an interesting discussion with which I hope health economists will engage.

An elicitation of utility for quality of life under prospect theory. Journal of Health Economics [RePEcPublished 2nd May 2016

Back in 1979, Kahneman and Tversky introduced prospect theory. Simply, this deviation from expected utility theory demonstrates that people value gains and losses from a given reference point differently, and that people’s decisions relate to probabilities in a nonlinear way. One of the key aspects of prospect theory is that it allows for loss aversion, which has been observed in the health context. We may therefore wish to develop methods for the estimation of QALYs that are based on prospect theory. This study demonstrates the limited validity of expected utility in estimating QALYs and shows how to estimate utility using prospect theory. A representative Dutch sample of 500 people was recruited for 2 experiments carried out online. Demographic and health state data were collected and participants were presented with possible gains and losses in quality of life within a 20%-100% interval associated with a specified reference point. Loss aversion was observed in both experiments, with evidence that responses were reference-dependent. Furthermore, there was risk aversion associated with both gains and losses. This undermines expected utility as a reasonable basis on which to estimate QALYs. Furthermore, the study found utility to be concave, such that a loss from 60% to 40% was perceived as smaller than a loss from 40% to 20%. This not only differs from the way in which we estimate QALYs, but also from the nature of prospect theory in the valuation of monetary outcomes. Expect to hear plenty more about PT-QALYs in the future.

Efficiency of health investment: education or intelligence? Health Economics [PubMedPublished 3rd May 2016

People with better education are healthier and live longer. But is this due to their education, or simply due to intelligence? It should go without saying that measuring intelligence, let alone separating it from the effects of education, is not straightforward. This study looks at whether education is associated with a higher efficiency of health investment. Health outcome is measured as survival and health investment as hospitalisation for a given condition. The authors then go on to consider the extent to which any benefit is due to intelligence. The data include 2570 Dutch individuals surveyed in 1952 in their final year of primary school and then followed up again in 1983 and 1993. The sample includes those people with hospitalisation records for 1995-2005 and mortality data for 1995-2011. A structural equation model is estimated to capture the impact of intelligence with the states ‘healthy’, ‘hospitalised’ and ‘dead’. Intelligence is modelled as a latent variable based on an IQ test and a vocabulary test at the age of 12. The analysis treats education choice as exogenous but controls for numerous socioeconomic and school-specific variables. People with higher education were less likely to die after a hospitalisation, though this relationship disappears once intelligence is accounted for. This suggests that the health investment advantage of the better educated is due to intelligence. There are plenty of limitations to the study in terms of the available data, but the findings nevertheless suggest that education per se might not be as beneficial to health as previous studies have shown.