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

Thesis Thursday: Cheryl Jones

On the third Thursday of every month, we speak to a recent graduate about their thesis and their studies. This month’s guest is Dr Cheryl Jones who has a PhD from the University of Manchester. If you would like to suggest a candidate for an upcoming Thesis Thursday, get in touch.

Title
The economics of presenteeism in the context of rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis
Supervisors
Katherine Payne, Suzanne Verstappen, Brenda Gannon
Repository link
https://www.research.manchester.ac.uk/portal/en/theses/the-economics-of-presenteeism-in-the-context-of-rheumatoid-arthritis-ankylosing-spondylitis-and-psoriatic-arthritis%288215e79a-925e-4664-9a3c-3fd42d643528%29.html

What attracted you to studying health-related presenteeism?

I was attracted to study presenteeism because it gave me a chance to address both normative and positive issues. Presenteeism, a concept related to productivity, is a controversial topic in the economic evaluation of healthcare technologies and is currently excluded from health economic evaluations, following the recommendation made by the NICE reference case. The reasons why productivity is excluded from economic evaluations are important and valid, however, there are some circumstances where excluding productivity is difficult to defend. Presenteeism offered an opportunity for me to explore and question the social value judgements that underpin economic evaluation methods with respect to productivity. In terms of positive issues related to presenteeism, research into the development of methods that can be used to measure and value presenteeism was (and still is) limited. This provided an opportunity to think creatively about the types of methods we could use, both quantitative and qualitative, to address and further methods for quantifying presenteeism.

Are existing tools adequate for measuring and valuing presenteeism in inflammatory arthritic conditions?

That is the question! Research into methods that can be used to quantify presenteeism is still in its infancy. Presenteeism is difficult to measure accurately because there are a lack of objective measures that can be used, for example, the number of cars assembled per day. As a consequence, many methods rely on self-report surveys, which tend to suffer from bias, such as reporting or recall bias. Methods that have been used to value presenteeism have largely focused on valuing presenteeism as a cost using the human capital approach (HCA: volume of presenteeism multiplied by a monetary factor). The monetary factor typically used to convert the volume of presenteeism into a cost value is wages. Valuing productivity using wages risks taking account of discriminatory factors that are associated with wages, such as age. There are also economic arguments that question whether the value of the wage truly reflects the value of productivity. My PhD focused on developing a method that values presenteeism as a non-monetary benefit, thereby avoiding the need to value it as a cost using wages. Overall, methods to measure and value presenteeism still have some way to go before a ‘gold standard’ can be established, however, there are many experts from many disciplines who are working to improve these methods.

Why was it important to conduct qualitative interviews as part of your research?

The quantitative component of my PhD was to develop an algorithm, using mapping methods, that links presenteeism with health status and capability measures. A study by Connolly et al. recommend conducting qualitative interviews to provide some evidence of face/content validity to establish whether a quantitative link between two measures (or concepts) is feasible and potentially valid. The qualitative study I conducted was designed to understand the extent to which the EQ-5D-5L, SF6D and ICECAP-C were able to capture those aspects of rheumatic conditions that negatively impact presenteeism. The results suggested that all three measures were able to capture those important aspects of rheumatic conditions that affect presenteeism; however, the results indicated that the SF6D would most likely be the most appropriate measure. The results from the quantitative mapping study identified the SF6D as the most suitable outcome measure able to predict presenteeism in working populations with rheumatic conditions. The advantage of the qualitative results was that it provided some evidence that explained why the SF6D was the more suitable measure rather than relying on speculation.

Is it feasible to predict presenteeism using outcome measures within economic evaluation?

I developed an algorithm that links presenteeism, measured using the Work Activity Productivity Impairment (WPAI) questionnaire, with health and capability. Health status was measured using the EQ-5D-5L and SF6D, and capability was measured using the ICECAP-A. The SF6D was identified as the most suitable measure to predict presenteeism in a population of employees with rheumatoid arthritis or ankylosing spondylitis. The results indicate that it is possible to predict presenteeism using generic outcome measures; however, the results have yet to be externally validated. The qualitative interviews provided evidence as to why the SF6D was the better predictor for presenteeism and the result gave rise to questions about the suitability of outcome measures given a specific population. The results indicate that it is potentially feasible to predict presenteeism using outcome measures.

What would be your key recommendation to a researcher hoping to capture the impact of an intervention on presenteeism?

Due to the lack of a ‘gold standard’ method for capturing the impact of presenteeism, I would recommend that the researcher reports and justifies their selection of the following:

  1. Provide a rationale that explains why presenteeism is an important factor that needs to be considered in the analysis.
  2. Explain how and why presenteeism will be captured and included in the analysis; as a cost, monetary benefit, or non-monetary benefit.
  3. Justify the methods used to measure and value presenteeism. It is important that the research clearly reports why specific tools, such as presenteeism surveys, have been selected for use.

Because there is no ‘gold standard’ method for measuring and valuing presenteeism and guidelines do not exist to inform the reporting of methods used to quantify presenteeism, it is important that the researcher reports and justifies their selection of methods used in their analysis.

Paul Mitchell’s journal round-up for 17th July 2017

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

What goes wrong with the allocation of domestic and international resources for HIV? Health Economics [PubMedPublished 7th July 2017

Investment in foreign aid is coming under considered scrutiny as a number of leading western economies re-evaluate their role in the world and their obligations to countries with developing economies. Therefore, it is important for those who believe in the benefits of such investments to show that they are being done efficiently. This paper looks at how funding for HIV is distributed both domestically and internationally across countries, using multivariate regression analysis with instruments to control for reverse causality between financing and HIV prevalence, and domestic and international financing. The author is also concerned about countries free riding on international aid and estimates how countries ought to be allocating national resources to HIV using quintile regression to estimate what countries have fiscal space for expanding their current spending domestically. The results of the study show that domestic expenditure relative to GDP per capita is almost unit elastic, whereas it is inelastic with regards to HIV prevalence. Government effectiveness (as defined by the World Bank indices) has a statistically significant effect on domestic expenditure, although it is nonlinear, with gains more likely when moving up from a lower level of government effectiveness. International expenditure is inversely related to GDP per capita and HIV prevalence, and positively with government effectiveness, albeit the regression models for international expenditure had poor explanatory power. Countries with higher GDP per capita tended to dedicate more money towards HIV, however, the author reckons there is $3bn of fiscal space in countries such as South Africa and Nigeria to contribute more to HIV, freeing up international aid for other countries such as Cameroon, Ghana, Thailand, Pakistan and Columbia. The author is concerned that countries with higher GDP should be able to allocate more to HIV, but feels there are improvements to be made in how international aid is distributed too. Although there is plenty of food for thought in this paper, I was left wondering how this analysis can help in aiding a better allocation of resources. The normative model of what funding for HIV ought to be is from the viewpoint that this is the sole objective of countries of allocating resources, which is clearly contestable (the author even casts doubt as to whether this is true for international funding of HIV). Perhaps the other demands faced by national governments (e.g. funding for other diseases, education etc.) can be better reflected in future research in this area.

Can pay-for-performance to primary care providers stimulate appropriate use of antibiotics? Health Economics [PubMed] [RePEcPublished 7th July 2017

Antibiotic resistance is one of the largest challenges facing global health this century. This study from Sweden looks to see whether pay for performance (P4P) can have a role in the prescription practices of GPs when it comes to treating children with respiratory tract infection. P4P was introduced on a staggered basis across a number of regions in Sweden to incentivise primary care to use narrow spectrum penicillin as a first line treatment, as it is said to have a smaller impact on resistance. Taking advantage of data from the Swedish Prescribed Drug Register between 2006-2013, the authors conducted a difference in difference regression analysis to show the effect P4P had on the share of the incentivised antibiotic. They find a positive main effect of P4P on drug prescribing of 1.1 percentage points, that is also statistically significant. Of interest, the P4P in Sweden under analysis here was not directly linked to salaries of GPs but the health care centre. Although there are a number of limitations with the study that the authors clearly highlight in the discussion, it is a good example of how to make the most of routinely available data. It also highlights that although the share of the less resistant antibiotic went up, the national picture of usage of antibiotics did not reduce in line with a national policy aimed at doing so during the same time period. Even though Sweden is reported to be one of the lower users of antibiotics in Europe, it highlights the need to carefully think through how targets are achieved and where incentives might help in some areas to meet such targets.

Econometric modelling of multiple self-reports of health states: the switch from EQ-5D-3L to EQ-5D-5L in evaluating drug therapies for rheumatoid arthritis. Journal of Health Economics Published 4th July 2017

The EQ-5D is the most frequently used health state descriptive system for the generation of utility values for quality-adjusted life years (QALYs) in economic evaluation. To improve sensitivity and reduce floor and ceiling effects, the EuroQol team developed a five level version (5L) compared to the previous three level (3L) version. This study adds to recent evidence in this area of the unforeseen consequences of making this change to the descriptive system and also the valuation system used for the 5L. Using data from the National Data Bank for Rheumatic Diseases, where both 3L and 5L versions were completed simultaneously alongside other clinical measures, the authors construct a mapping between both versions of EQ-5D, informed by the response levels and the valuation systems that have been developed in the UK for the measures. They also test their mapping estimates on a previous economic evaluation for rheumatoid arthritis treatments. The descriptive results show that although there is a high correlation between both versions, and the 5L version achieves its aim of greater sensitivity, there is a systematic difference in utility scores generated using both versions, with an average 87% of the score of the 3L recorded compared to the 5L. Not only are there differences highlighted between value sets for the 3L and 5L but also the responses to dimensions across measures, where the mobility and pain dimensions do not align as one would expect. The new mapping developed in this paper highlights some of the issues with previous mapping methods used in practice, including the assumption of independence of dimension levels from one another that was used while the new valuation for the 5L was being developed. Although the case study they use to demonstrate the effect of using the different approaches in practice did not result in a different cost-effectiveness result, the study does manage to highlight that the assumption of 3L and 5L versions being substitutes for one another, both in terms of descriptive systems and value sets, does not hold. Although the authors are keen to highlight the benefits of their new mapping that produces a smooth distribution from actual to predicted 5L, decision makers will need to be clear about what descriptive system they now want for the generation of QALYs, given the discrepancies between 3L and 5L versions of EQ-5D, so that consistent results are obtained from economic evaluations.

Credits