Chris Sampson’s journal round-up for 13th March 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.

The effects of exercise and relaxation on health and wellbeing. Health Economics [PubMedPublished 9th Month 2017

Encouraging self-management of health sounds like a good idea, but the evidence is pretty weak. As economists, we know that something must be displaced in order to do it. This study considers the opportunity cost of time and how it might affect self-management activity and any associated benefits. Employment and education are likely to increase income and thus facilitate more expenditure on exercise. But the time cost of exercise is also likely to increase, meaning that the impact on demand is ambiguous. The study uses data from a trial of self-management support that included people with diabetes, COPD or IBS. EQ-5D, self-assessed health and the amount of time spent ‘being happy’ were all collected. Information was available for 12 different self-management activities, including ‘do exercises’ and ‘rest and relax’, and the extent to which individuals did these. Outcomes for 3,472 people at 12-month follow-up are estimated, controlling for outcomes at baseline and 6 months. The study assumes that employment and education affect health via their influence on exercise and relaxation. That seems a bit questionable and the other 10 self-management indicators could have been looked at to test this. People in full-time employment were 11 percentage points less likely to use relaxation to manage their condition, suggesting that the substitution effect on time dominates as the opportunity cost of self-management increases. Having a degree or professional qualification increased the probability of using exercise by 5 percentage points, suggesting that the income effect dominates. Those who are more likely to use either exercise or relaxation are also more likely to do the other. An interesting suggestion is that time preference might explain things here. Those with more education may prefer to exercise (as an investment) than to get the instant gratification of rest and relaxation. It’s important that policy recommendations take into consideration the fact that different groups will respond differently to incentives for self-management, at least partly due to their differing time constraints. The thing I find most interesting is the analysis of the different outcomes (something I’ve worked on). Exercise is found to improve self-assessed health, while relaxation increases happiness. Neither exercise or relaxation had a (statistically significant) effect on EQ-5D. Depending on your perspective, this either suggests that the EQ-5D is failing to identify important changes in broad health-related domains or it means that self-management does not achieve the goals (QALYs to the max) of the health service.

New findings from the time trade-off for income approach to elicit willingness to pay for a quality adjusted life year. The European Journal of Health Economics [PubMedPublished 8th March 2017

The question ‘what is a QALY worth’ could invoke any number of reactions in a health economist, from chin scratching to eye rolling. The perspective that we’re probably most familiar with in the UK is that the value of a QALY is the value of health foregone in order to achieve it (i.e. opportunity cost within the health care perspective). An alternative perspective is that the value of a QALY is the consumption value of health; how much consumption would individuals be willing to give up in order to obtain an additional QALY? This second perspective facilitates a broader societal perspective. It can tell us whether or not the budget is set at an appropriate level, while the health care perspective can only take the budget as given. This study relates mainly to decisions made with the ‘consumption value’ perspective. One approach that has been proposed is to assess willingness to pay for a QALY using a time trade-off exercise that incorporates trade-offs between length and quality of life and income. This study builds on the original work by using a multiplicative utility function to estimate willingness to pay and also bringing in prospect theory to allow for reference dependence and loss aversion. 550 participants were asked to choose between living 10 years in their current health state with their current salary or to live a reduced number of years in their current health state with a luxury income (pre-specified by the participant). Respondents were also asked to make a similar choice, but framed as a loss of income, between living 10 years at a subsistence income or fewer years with their current income. A quality of life trade-off exercise was also conducted, in which people traded reduced health and a lower income. The findings support the predictions of prospect theory. Loss aversion is found to be stronger for duration than for quality of life. Individuals were more willing to sacrifice life years to move from subsistence income to current income than to move from current income to luxury income. The results imply that quality of life and income are closer substitutes than longevity and income. That makes sense, given the all-or-nothing nature of being alive. Crucially, the findings highlight the need to better understand the shape of the underlying lifetime utility function. In all tasks, more than half of respondents were either non-traders or over-traded, indicating a negative willingness to pay. That should give pause for thought when it comes to any aggregation of the results. Willingness to pay studies often throw up more questions than answers. This one does so more than most, particularly about sources of bias in people’s responses. The authors identify plenty of opportunities for future research.

Beyond QALYs: multi-criteria based estimation of maximum willingness to pay for health technologies. The European Journal of Health Economics [PubMed] Published 3rd March 2017

Life is messy. Evaluating things in terms of a single outcome, whether that be QALYs, £££s or whatever, is necessarily simplifying and restrictive. That’s not necessarily a bad thing, but we’d do well to bear it in mind. In this paper, Erik Nord sets out a kind of cost value analysis that does away with QALYs (gasp!). The author starts by outlining some familiar criticisms of the QALY approach, such as its failure to consider the inherent value of life and people’s differing reference points. Generally, I see these as features rather than bugs, and it isn’t QALYs themselves in the crosshairs here so much as cost-per-QALY analysis. The proposed method flips current practice by putting societal preferences about fair and efficient resource allocation before attaching values to the outcomes. As such, it acknowledges the fact that society’s preferences for gains in quality of life differ from those for gains in length of life. For example, society may prefer treating the more severely ill (independent of age) but also exhibit a ‘fair innings’ preference that is related to age. Thus, quality and quantity of life are disaggregated and the QALY is no more. A set of tables is presented that can be read to assess ‘value’ in alternative scenarios, given the assumptions set out in the paper. There is merit in the approach and a lot that I like about the possibilities of its use. But for me, the whole thing was made less attractive by the way it is presented in the paper. The author touts willingness to pay – for quality of life gains and for longevity gains – as the basis for value. Anything that makes resource allocation more dependent on willingness to pay values for things without a price (health, life) is a big no-no for me. But the method doesn’t depend on that. Furthermore, as is so often the case, most of the criticisms within relate to ways of using QALYs, rather than the fundamental basis for their estimation. This only weakens the argument for an alternative. But I can think of plenty of problems with QALYs, some of which might be addressed by this alternative approach. It’s unfortunate that the paper doesn’t outline how these more fundamental problems might be addressed. There may come a day when we do away with QALYs, and we may end up doing something similar to what’s outlined here, but we need to think harder about how this alternative is really better.


Alastair Canaway’s journal round-up for 12th 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.

Question order sensitivity of subjective well-being measures: focus on life satisfaction, self-rated health, and subjective life expectancy in survey instruments. Quality of Life Research [PubMed] Published 30th April 2016

It’s interesting to see an ‘old’ and well known issue rearing its head within the health economics literature. In this case, the focus is on ordering bias within wellbeing questionnaires. It is established within the psychometric and psychological literature that the location of a question within a survey can influence how respondents interpret the meaning of the question, and therefore their answers. This study sought to empirically examine how ordering in subjective well-being measures (life satisfaction, self-rated health, and subjective life expectancy) affected answers. Given ordering bias is an established concept, it wasn’t too surprising to find notable ordering bias depending on how the questionnaire was ordered. For example, as hypothesised by the authors, placing self-rated health immediately before life satisfaction within the survey led to different values compared to when placed apart. For well-being research, the paper has important implications, particularly in how to best order questionnaires to reduce the impact of prior questions on answers, e.g. keeping self-rated health and life satisfaction questions apart to encourage respondents to independently evaluate each question. Ordering bias is one of those issues that most researchers are aware of, but tend to forget about. As much as anything I feel this is for pragmatic reasons, for example, in terms of ease of producing case report forms and also for facilitating data entry within trials. Ideally, we probably should be randomising the order of questionnaires, whether we can persuade wider trial teams that this is necessary remains to be seen.

You sneeze, you lose: The impact of pollen exposure on cognitive performance during high-stakes high school exams. Journal of Health Economics [PubMed] [RePEcPublished September 2016

As a ‘summer sneezer’ and someone with poor exam results in year 9, it was of great interest to read this article. It is known that health and productivity are intrinsically linked, indeed productivity costs related to health are commonly discussed within health economics circles. Elsewhere there are studies that have identified pollution levels as having significant effects on labour productivity and supply. As any fellow hay fever (seasonal allergic rhinitis) sufferers will attest, hay fever has a direct negative impact on wellbeing. Hay fever is relatively prevalent with over one in five people being reported to suffer (in the Norwegian setting at least). This study combined a large administrative dataset from the Norwegian high school system with daily pollen counts from measurement stations across Norway. Student exam data were matched with location of exams and the pollen count for the area in which the exam took place. Fixed effect panel data methods were used to analyse the data. The primary result found that one standard deviation increase in pollen levels led to a decrease in a student’s exam score by about 2.5% of a standard deviation, the implication of this is that for allergic students, this negative effect is approximately 10% of a standard deviation. This is a notable margin. The paper has an interesting discussion on the potential long term impact of hay fever on allergic students, and their future prospects e.g. impact on university enrolment. To avoid such impacts the paper emphasises the need to diagnose early and optimise treatment for hay fever in children. One final point (and word of caution) would be that the methods don’t prove causality, however as a hay fever sufferer, it was very interesting nonetheless to consider how the condition may have impacted upon my own performance at school.

The fatter are happier in Indonesia. Quality of Life Research [PubMed] Published 31st August 2016

An eye-catching title. In developed countries, being overweight and obese typically has negative connotations, and studies repeatedly suggest this is the case: those who are overweight are less happy. In developing countries however, this is not necessarily true. The paper offers the following reason for this: wealth and obesity are positively correlated in such countries, and likewise, happiness and wealth are positively related. Those who are poor in developing countries literally cannot afford to be obese. In contrast, in developed countries, even lower socioeconomic classes can afford to be obese (and obesity is indeed more prevalent in these classes). With this in mind, this study sought to determine how obesity and happiness were related in Indonesia. The study used a large long term survey of over 22,000 participants over a long time period. As hypothesised, the study found there to be a positive association between obesity and self-reported happiness within Indonesia. The paper in a roundabout way suggests that a different approach to evaluating obesity prevention is required in the developing world. I’m not sure this is necessarily the case, in my experience it is rare to assess obesity prevention interventions with respect to ‘happiness’. It takes me back to a previous journal round-up discussing the maximand within economic evaluation. Obesity, if not immediately, eventually is associated with poor health, therefore there is nothing to suggest that an evaluative framework that seeks to maximise health over happiness will not be sufficient. There are many issues related to the long term evaluation of obesity prevention interventions, particularly those focussed in children (as outlined here), however I think the case stated in this paper is a bit of red herring.

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

Chris Sampson’s journal round-up for 29th August 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.

Health or happiness? A note on trading off health and happiness in rationing decisions. Value in Health Published 23rd August 2016

Health problems can impact both health and happiness. It seems obvious that individuals would attribute value to the happiness provided by a health technology over and above any health improvement. But what about ‘public’ views? Would people be willing to allocate resources to health care for other people on the basis of the happiness it provides? This study reports on a web-based survey in which 1015 people were asked to make resource allocation choices about groups of patients standing to gain varying degrees of health and/or happiness. Three scenarios were presented – one varying only happiness levels, one varying only health and another varying both. Unfortunately the third scenario was not analysed due to “the many inconsistent choices”. About half of respondents were not willing to make any trade-offs in happiness and health. Those who did make choices attached more weight to health on average. But there were some effects associated with the starting levels of health and happiness – people were less willing to discriminate between groups when starting health (or happiness) was lower, and more weight was given to health. There are a selection of potential biases associated with the responses to the questions, which the authors duly discuss.

Determinants of change in the cost-effectiveness threshold. Medical Decision Making [PubMedPublished 23rd August 2016

Set aside for the moment any theoretical concerns you might have with the ‘threshold’ approach to decision making in health care resource allocation. If we are going to use a willingness to pay threshold, how might it alter over time and in response to particular stimuli? This paper tackles that question using comparative statics and the idea of the ‘cost-effectiveness bookshelf’. If you haven’t come across it before, simply imagine a bookshelf with a book for each technology. The height of the books is determined by the ICER and their width by the budget impact; they’re lined up from shortest to tallest. This paper focuses on the introduction of technologies with ‘marginal’ budget impact, requiring the displacement of one existing technology. But a key idea to remember is that for technologies with large ‘non-marginal’ budget impacts – that is, requiring displacement of more than one existing technology – the threshold will be a weighted average of those technologies that are displaced. The authors describe the impact of changes in 4 different determinants of the threshold: i) the health budget, ii) demand for existing technologies, iii) technical efficiency of existing technologies and iv) funding for new technologies. Some changes (e.g. an increase in the health budget) have unambiguous impacts on the threshold (e.g. to increase it). Others have ambiguous effects – for example a decrease in the cost of a marginal technology might decrease the threshold through reduction of the ICER, or increase the threshold by reducing the budget impact so much that an additional technology could be funded. There’s a nice discussion towards the end about relaxing the assumptions. What if the budget isn’t fixed? What if we aren’t sure we’ve got the books in the right order? The bookshelf analogy is a starting point for these kinds of discussions. The article is an easy read and a good reference point for the threshold debate, even if its practical usefulness may be limited when lining up the NHS’s books seems like a pipedream.

Update to the report of nationally representative values for the noninstitutionalized US adult population for five health-related quality-of-life scores. Value in Health Published 21st August 2016

This paper does what it says on the tin, but it is a useful reference and worth knowing about. The last lot were published in 2006, so this paper is an update to that one using data from 2011. The measures reported are: i) self-rated health, ii) SF-12 mental subscale and (iii) physical subscale, iv) SF-6D and v) Quality of Well-Being Scale. Data come from the Medical Expenditures Panel Survey and the National Health Interview Survey, with 23,906 subjects in the former and 32,242 in the latter. Results are presented by age group (in decades) and by sex. So, for example, we can see that 20-29 year old women reported an average SF-6D index score of 0.809 while for 80-89 year olds the mean was 0.698. For almost all age groups and all measures, men reported higher scores than women. Interestingly, mean SF-6D scores were on average lower than in the 2001 data reported in the previous study.

Use of cost-effectiveness analysis to compare the efficiency of study identification methods in systematic reviews. Systematic Reviews [PubMed] Published 17th August 2016

Health economists have (or at least should have) a bit of a comparative advantage when it comes to economic evaluation. I’ve often thought that we should be leading the way in methods of economic evaluation in economics beyond the subject matter of health, and maybe into other fields. So I was pleased to see this paper using cost-effectiveness analysis for a new purpose. Often, systematic reviews can be mammoth tasks and potentially end up being of little value. Certainly at the margin there are things often done as part of a review (let’s say, including EconLit in a principally clinical review) that in the end prove to be pretty pointless. This study evaluates the cost-effectiveness of 4 alternative approaches to screening titles and abstracts as part of a systematic review. The 4 alternatives are i) ‘double screening’, which is the classic approach used by Cochrane et al whereby two researchers independently review abstracts and then meet to consider disagreements, ii) ‘safety first’, which is a variation on double screening whereby citations are only excludable if both reviewers identify them as such iii) ‘single screening’ with just one reviewer and iv) ‘single screening with text mining’ in which a machine learning process ranks studies by the likelihood of their inclusion. The outcome measure was the number of citations saved from inappropriate exclusion. It’s a big review, starting with 12,477 citations. There wasn’t much in it outcomes-wise, with at most 169 eligible studies and at least 161. But the incremental cost of double screening, compared with single screening plus text mining, was £37,279. This meant an ICER of £4660 per extra study, which seems like a lot. There are some limitations to the study, and the results clearly aren’t generalisable to all reviews. But it’s easy to see how studies-within-studies like this can help guide future research.

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