Chris Sampson’s journal round-up for 11th March 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.

Identification, review, and use of health state utilities in cost-effectiveness models: an ISPOR Good Practices for Outcomes Research Task Force report. Value in Health [PubMed] Published 1st March 2019

When modellers select health state utility values to plug into their models, they often do it in an ad hoc and unsystematic way. This ISPOR Task Force report seeks to address that.

The authors discuss the process of searching, reviewing, and synthesising utility values. Searches need to use iterative techniques because evidence requirements develop as a model develops. Due to the scope of models, it may be necessary to develop multiple search strategies (for example, for different aspects of disease pathways). Searches needn’t be exhaustive, but they should be systematic and transparent. The authors provide a list of factors that should be considered in defining search criteria. In reviewing utility values, both quality and appropriateness should be considered. Quality is indicated by the precision of the evidence, the response rate, and missing data. Appropriateness relates to the extent to which the evidence being reviewed conforms to the context of the model in which it is to be used. This includes factors such as the characteristics of the study population, the measure used, value sets used, and the timing of data collection. When it comes to synthesis, the authors suggest it might not be meaningful in most cases, because of variation in methods. We can’t pool values if they aren’t (at least roughly) equivalent. Therefore, one approach is to employ strict inclusion criteria (e.g only EQ-5D, only a particular value set), but this isn’t likely to leave you with much. Meta-regression can be used to analyse more dissimilar utility values and provide insight into the impact of methodological differences. But the extent to which this can provide pooled values for a model is questionable, and the authors concede that more research is needed.

This paper can inform that future research. Not least in its attempt to specify minimum reporting standards. We have another checklist, with another acronym (SpRUCE). The idea isn’t so much that this will guide publications of systematic reviews of utility values, but rather that modellers (and model reviewers) can use it to assess whether the selection of utility values was adequate. The authors then go on to offer methodological recommendations for using utility values in cost-effectiveness models, considering issues such as modelling technique, comorbidities, adverse events, and sensitivity analysis. It’s early days, so the recommendations in this report ought to be changed as methods develop. Still, it’s a first step away from the ad hoc selection of utility values that (no doubt) drives the results of many cost-effectiveness models.

Estimating the marginal cost of a life year in Sweden’s public healthcare sector. The European Journal of Health Economics [PubMed] Published 22nd February 2019

It’s only recently that health economists have gained access to data that enables the estimation of the opportunity cost of health care expenditure on a national level; what is sometimes referred to as a supply-side threshold. We’ve seen studies in the UK, Spain, Australia, and here we have one from Sweden.

The authors use data on health care expenditure at the national (1970-2016) and regional (2003-2016) level, alongside estimates of remaining life expectancy by age and gender (1970-2016). First, they try a time series analysis, testing the nature of causality. Finding an apparently causal relationship between longevity and expenditure, the authors don’t take it any further. Instead, the results are based on a panel data analysis, employing similar methods to estimates generated in other countries. The authors propose a conceptual model to support their analysis, which distinguishes it from other studies. In particular, the authors assert that the majority of the impact of expenditure on mortality operates through morbidity, which changes how the model should be specified. The number of newly graduated nurses is used as an instrument indicative of a supply-shift at the national rather than regional level. The models control for socioeconomic and demographic factors and morbidity not amenable to health care.

The authors estimate the marginal cost of a life year by dividing health care expenditure by the expenditure elasticity of life expectancy, finding an opportunity cost of €38,812 (with a massive 95% confidence interval). Using Swedish population norms for utility values, this would translate into around €45,000/QALY.

The analysis is considered and makes plain the difficulty of estimating the marginal productivity of health care expenditure. It looks like a nail in the coffin for the idea of estimating opportunity costs using time series. For now, at least, estimates of opportunity cost will be based on variation according to geography, rather than time. In their excellent discussion, the authors are candid about the limitations of their model. Their instrument wasn’t perfect and it looks like there may have been important confounding variables that they couldn’t control for.

Frequentist and Bayesian meta‐regression of health state utilities for multiple myeloma incorporating systematic review and analysis of individual patient data. Health Economics [PubMed] Published 20th February 2019

The first paper in this round-up was about improving practice in the systematic review of health state utility values, and it indicated the need for more research on the synthesis of values. Here, we have some. In this study, the authors conduct a meta-analysis of utility values alongside an analysis of registry and clinical study data for multiple myeloma patients.

A literature search identified 13 ‘methodologically appropriate’ papers, providing 27 health state utility values. The EMMOS registry included data for 2,445 patients in 22 counties and the APEX clinical study included 669 patients, all with EQ-5D-3L data. The authors implement both a frequentist meta-regression and a Bayesian model. In both cases, the models were run including all values and then with a limited set of only EQ-5D values. These models predicted utility values based on the number of treatment classes received and the rate of stem cell transplant in the sample. The priors used in the Bayesian model were based on studies that reported general utility values for the presence of disease (rather than according to treatment).

The frequentist models showed that utility was low at diagnosis, higher at first treatment, and lower at each subsequent treatment. Stem cell transplant had a positive impact on utility values independent of the number of previous treatments. The results of the Bayesian analysis were very similar, which the authors suggest is due to weak priors. An additional Bayesian model was run with preferred data but vague priors, to assess the sensitivity of the model to the priors. At later stages of disease (for which data were more sparse), there was greater uncertainty. The authors provide predicted values from each of the five models, according to the number of treatment classes received. The models provide slightly different results, except in the case of newly diagnosed patients (where the difference was 0.001). For example, the ‘EQ-5D only’ frequentist model gave a value of 0.659 for one treatment, while the Bayesian model gave a value of 0.620.

I’m not sure that the study satisfies the recommendations outlined in the ISPOR Task Force report described above (though that would be an unfair challenge, given the timing of publication). We’re told very little about the nature of the studies that are included, so it’s difficult to judge whether they should have been combined in this way. However, the authors state that they have made their data extraction and source code available online, which means I could check that out (though, having had a look, I can’t find the material that the authors refer to, reinforcing my hatred for the shambolic ‘supplementary material’ ecosystem). The main purpose of this paper is to progress the methods used to synthesise health state utility values, and it does that well. Predictably, the future is Bayesian.

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Rita Faria’s journal round-up for 4th March 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.

Cheap and dirty: the effect of contracting out cleaning on efficiency and effectiveness. Public Administration Review Published 25th February 2019

Before I was a health economist, I used to be a pharmacist and worked for a well-known high street chain for some years. My impression was that the stores with in-house cleaners were cleaner, but I didn’t know if this was a true difference, my leftie bias or my small sample size of 2! This new study by Shimaa Elkomy, Graham Cookson and Simon Jones confirms my suspicions, albeit in the context of NHS hospitals, so I couldn’t resist to select it for my round-up.

They looked at how contracted-out services fare in terms of perceived cleanliness, costs and MRSA rate in NHS hospitals. MRSA is a type of hospital-associated infection that is affected by how clean a hospital is.

They found that contracted-out services are cheaper than in-house cleaning, but that perceived cleanliness is worse. Importantly, contracted-out services increase the MRSA rate. In other words, contracting-out cleaning services could harm patients’ health.

This is a fascinating paper that is well worth a read. One wonders if the cost of managing MRSA is more than offset by the savings of contracting-out services. Going a step further, are in-house services cost-effective given the impact on patients’ health and costs of managing infections?

What’s been the bang for the buck? Cost-effectiveness of health care spending across selected conditions in the US. Health Affairs [PubMed] Published 1st January 2019

Staying on the topic of value for money, this study by David Wamble and colleagues looks at the extent to which the increased spending in health care in the US has translated into better health outcomes over time.

It’s clearly reassuring that, for 6 out of the 7 conditions they looked at, health outcomes have improved in 2015 compared to 1996. After all, that’s the goal of investing in medical R&D, although it remains unclear how much of this difference can be attributed to health care versus other things that have happened at the same time that could have improved health outcomes.

I wasn’t sure about the inflation adjustment for the costs, so I’d be grateful for your thoughts via comments or Twitter. In my view, we would underestimate the costs if we used medical price inflation indices. This is because these indices reflect the specific increase in prices in health care, such as due to new drugs being priced high at launch. So I understand that the main results use the US Consumer Price Index, which means that this reflects the average increase in prices over time rather than the increase in health care.

However, patients may not have seen their income rise with inflation. This means that the cost of health care may represent a disproportionally greater share of people’s income. And that the inflation adjustment may downplay the impact of health care costs on people’s pockets.

This study caught my eye and it is quite thought-provoking. It’s a good addition to the literature on the cost-effectiveness of US health care. But I’d wager that the question remains: to what extent is today’s medical care better value for money that in the past?

The dos and don’ts of influencing policy: a systematic review of advice to academics. Palgrave Communications Published 19th February 2019

We all would like to see our research findings influence policy, but how to do this in practice? Well, look no further, as Kathryn Oliver and Paul Cairney reviewed the literature, summarised it in 8 key tips and thought through their implications.

To sum up, it’s not easy to influence policy; advice about how to influence policy is rarely based on empirical evidence, and there are a few risks to trying to become a mover-and-shaker in policy circles.

They discuss three dilemmas in policy engagement. Should academics try to influence policy? How should academics influence policy? What is the purpose of academics’ engagement in policy making?

I particularly enjoyed reading about the approaches to influence policy. Tools such as evidence synthesis and social media should make evidence more accessible, but their effectiveness is unclear. Another approach is to craft stories to create a compelling case for the policy change, which seems to me to be very close to marketing. The third approach is co-production, which they note can give rise to accusations of bias and can have some practical challenges in terms of intellectual property and keeping one’s independence.

I found this paper quite refreshing. It not only boiled down the advice circulating online about how to influence policy into its key messages but also thought through the practical challenges in its application. The impact agenda seems to be here to stay, at least in the UK. This paper is an excellent source of advice on the risks and benefits of trying to navigate the policy world.

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Chris Sampson’s journal round-up for 14th May 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.

A practical guide to conducting a systematic review and meta-analysis of health state utility values. PharmacoEconomics [PubMed] Published 10th May 2018

I love articles that outline the practical application of a particular method to solve a particular problem, especially when the article shares analysis code that can be copied and adapted. This paper does just that for the case of synthesising health state utility values. Decision modellers use utility values as parameters. Most of the time these are drawn from a single source which almost certainly introduces some kind of bias to the resulting cost-effectiveness estimates. So it’s better to combine all of the relevant available information. But that’s easier said than done, as numerous researchers (myself included) have discovered. This paper outlines the various approaches and some of the merits and limitations of each. There are some standard stages, for which advice is provided, relating to the identification, selection, and extraction of data. Those are by no means simple tasks, but the really tricky bit comes when you try and pool the utility values that you’ve found. The authors outline three strategies: i) fixed effect meta-analysis, ii) random effects meta-analysis, and iii) mixed effects meta-regression. Each is illustrated with a hypothetical example, with Stata and R commands provided. Broadly speaking, the authors favour mixed effects meta-regression because of its ability to identify the extent of similarity between sources and to help explain heterogeneity. The authors insist that comparability between sources is a precondition for pooling. But the thing about health state utility values is that they are – almost by definition – never comparable. Different population? Not comparable. Different treatment pathway? No chance. Different utility measure? Ha! They may or may not appear to be similar statistically, but that’s totally irrelevant. What matters is whether the decision-maker ‘believes’ the values. If they believe them then they should be included and pooled. If decision-makers have reason to believe one source more or less than another then this should be accounted for in the weighting. If they don’t believe them at all then they should be excluded. Comparability is framed as a statistical question, when in reality it is a conceptual one. For now, researchers will have to tackle that themselves. This paper doesn’t solve all of the problems around meta-analysis of health state utility values, but it does a good job of outlining methodological developments to date and provides recommendations in accordance with them.

Unemployment, unemployment duration, and health: selection or causation? The European Journal of Health Economics [PubMed] Published 3rd May 2018

One of the major socioeconomic correlates of poor health is unemployment. It appears not to be very good for you. But there’s an obvious challenge here – does unemployment cause ill-health, or are unhealthy people just more likely to be unemployed? Both, probably, but that answer doesn’t make for clear policy solutions. This paper – following a large body of literature – attempts to explain what’s going on. Its novelty comes in the way the author considers timing and distinguishes between mental and physical health. The basis for the analysis is that selection into unemployment by the unhealthy ought to imply time-constant effects of unemployment on health. On the other hand, the negative effect of unemployment on health ought to grow over time. Using seven waves of data from the German Socio-economic Panel, a sample of 17,000 people (chopped from 48,000) is analysed, of which around 3,000 experienced unemployment. The basis for measuring mental and physical health is summary scores from the SF-12. A fixed-effects model is constructed based on the dependence of health on the duration and timing of unemployment, rather than just the occurrence of unemployment per se. The author finds a cumulative effect of unemployment on physical ill-health over time, implying causation. This is particularly pronounced for people unemployed in later life, and there was essentially no impact on physical health for younger people. The longer people spent unemployed, the more their health deteriorated. This was accompanied by a strong long-term selection effect of less physically healthy people being more likely to become unemployed. In contrast, for mental health, the findings suggest a short-term selection effect of people who experience a decline in mental health being more likely to become unemployed. But then, following unemployment, mental health declines further, so the balance of selection and causation effects is less clear. In contrast to physical health, people’s mental health is more badly affected by unemployment at younger ages. By no means does this study prove the balance between selection and causality. It can’t account for people’s anticipation of unemployment or future ill-health. But it does provide inspiration for better-targeted policies to limit the impact of unemployment on health.

Different domains – different time preferences? Social Science & Medicine [PubMed] Published 30th April 2018

Economists are often criticised by non-economists. Usually, the criticisms are unfounded, but one of the ways in which I think some (micro)economists can have tunnel vision is in thinking that preferences elicited with respect to money exhibit the same characteristics as preferences about things other than money. My instinct tells me that – for most people – that isn’t true. This study looks at one of those characteristics of preferences – namely, time preferences. Unfortunately for me, it suggests that my instincts aren’t correct. The authors outline a quasi-hyperbolic discounting model, incorporating both short-term present bias and long-term impatience, to explain gym members’ time preferences in the health and monetary domains. A survey was conducted with members of a chain of fitness centres in Denmark, of which 1,687 responded. Half were allocated to money-related questions and half to health-related questions. Respondents were asked to match an amount of future gains with an amount of immediate gains to provide a point of indifference. Health problems were formulated as back pain, with an EQ-5D-3L level 2 for usual activities and a level 2 for pain or discomfort. The findings were that estimates for discount rates and present bias in the two domains are different, but not by very much. On average, discount rates are slightly higher in the health domain – a finding driven by female respondents and people with more education. Present bias is the same – on average – in each domain, though retired people are more present biased for health. The authors conclude by focussing on the similarity between health and monetary time preferences, suggesting that time preferences in the monetary domain can safely be applied in the health domain. But I’d still be wary of this. For starters, one would expect a group of gym members – who have all decided to join the gym – to be relatively homogenous in their time preferences. Findings are similar on average, and there are only small differences in subgroups, but when it comes to health care (even public health) we’re never dealing with average people. Targeted interventions are increasingly needed, which means that differential discount rates in the health domain – of the kind identified in this study – should be brought into focus.

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