Chris Sampson’s journal round-up for 9th October 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.

Evaluating the relationship between visual acuity and utilities in patients with diabetic macular edema enrolled in intravitreal aflibercept studies. Investigative Ophthalmology & Visual Science [PubMed] Published October 2017

Part of my day job involves the evaluation of a new type of screening programme for diabetic eye disease, including the use of a decision analytic model. Cost-effectiveness models usually need health state utility values for parameters in order to estimate QALYs. There are some interesting challenges in evaluating health-related quality of life in the context of vision loss; does vision in the best eye or worst eye affect quality of life most; do different eye diseases have different impacts independent of sight loss; do generic preference-based measures even work in this context? This study explores some of these questions. It combines baseline and follow-up EQ-5D and VFQ-UI (a condition-specific preference-based measure) responses from 1,320 patients from 4 different studies, along with visual acuity data. OLS and random effects panel models are used to predict utility values dependent on visual acuity and other individual characteristics. Best-seeing eye seems to be a more important determinant than worst-seeing eye, which supports previous studies. But worst-seeing eye is still important, with about a third of the impact of best-seeing eye. So economic evaluations shouldn’t ignore the bilateral nature of eye disease. Visual acuity – in both best- and worst-seeing eye – was more strongly associated with the condition-specific VFQ-UI than with the EQ-5D index, leading to better predictive power, which is not a big surprise. One way to look at this is that the EQ-5D underestimates the impact of visual acuity on utility. An alternative view could be that the VFQ-UI valuation process overestimates the impact of visual acuity on utility. This study is a nice demonstration of the fact that selecting health state utility values for a model-based economic evaluation is not straightforward. Attention needs to be given to the choice of measure (e.g. generic or condition-specific), but also to the way states are defined to allow for accurate utility values to be attached.

Do capability and functioning differ? A study of U.K. survey responses. Health Economics [PubMed] Published 24th September 2017

I like the capability approach in theory, but not in practice. I’ve written before about some of my concerns. One of them is that we don’t know whether capability measures (such as the ICECAP) offer anything beyond semantic nuance. This study sought to address that. A ‘functioning and capability’ instrument was devised, which reworded the ICECAP-A by changing phrases like “I am able to be” to phrases like “I am”, so that each question could have a ‘functioning’ version as well as a ‘capability’ version. Then, both the functioning and capability versions of the domains were presented in tandem. Questionnaires were sent to 1,627 individuals who had participated in another study about spillover effects in meningitis. Respondents (n=1,022) were family members of people experiencing after-effects of meningitis. The analysis focusses on the instances where capabilities and functionings diverge. Across the sample, 34% of respondents reported a difference between capability and functioning on at least one domain. For all domain-level responses, 12% were associated with higher capability than functioning, while 2% reported higher functioning. Some differences were observed between different groups of people. Older people tended to be less likely to report excess capabilities, while those with degree-level education reported greater capabilities. Informal care providers had lower functionings and capabilities but were more likely to report a difference between the two. Women were more likely to report excess capabilities in the ‘attachment’ domain. These differences lead the author to conclude that the wording of the ICECAP measure enables researchers to capture something beyond functioning, and that the choice of a capability measure could lead to different resource allocation decisions. I’m not convinced. The study makes an error that is common in this field; it presupposes that the changes in wording successfully distinguish between capabilities and functionings. This is implemented analytically by dropping from the primary analysis the cases where capabilities exceeded functionings, which are presumed to be illogical. If we don’t accept this presupposition (and we shouldn’t) then the meaning of the findings becomes questionable. The paper does outline most of the limitations of the study, but it doesn’t dedicate much space to alternative explanations. One is to do with the distinction between ‘can’ and ‘could’. If people answer ‘capability’ questions with reference to future possibilities, then the difference could simply be driven by optimism about future functionings. This future-reference problem is most obvious in the ‘achievement and progress’ domain, which incidentally, in this study, was the domain with the greatest probability of showing a discrepancy between capabilities and functionings. Another alternative explanation is that showing someone two slightly different questions coaxes them into making an artificial distinction that they wouldn’t otherwise make. In my previous writing on this, I suggested that two things needed to be identified. The first was to see whether people give different responses with the different wording. This study goes some way towards that, which is a good start. The second was to see whether people value states defined in these ways any differently. Until we have answers to both these questions I will remain sceptical about the implications of the ICECAP’s semantic nuance.

Estimating a constant WTP for a QALY—a mission impossible? The European Journal of Health Economics [PubMed] Published 21st September 2017

The idea of estimating willingness to pay (WTP) for a QALY has fallen out of fashion. It’s a nice idea in principle but, as the title of this paper suggests, it’s not easy to come up with a meaningful answer. One key problem has been that WTP for a QALY is not constant in the number of QALYs being gained – that is, people are willing to pay less (at the margin) for greater QALY gains. But maybe that’s OK. NICE and their counterparts tend not to use a fixed threshold but rather a range: £20,000-£30,000 per QALY, say. So maybe the variability in WTP for a QALY can be reflected in this range. This study explores some of the reasons – including uncertainty – for differences in elicited WTP values for a QALY. A contingent valuation exercise was conducted using a 2014 Internet panel survey of 1,400 Swedish citizens. The survey consisted 21 questions about respondents’ own health, sociodemographics, prioritisation attitudes, WTP for health improvements, and a societal decision-making task. Respondents were randomly assigned to one of five scenarios with different magnitudes and probabilities of health gain, with yes/no responses for five different WTP ‘bids’. The estimated WTP for a QALY – using the UK EQ-5D-3L tariff – was €17,000. But across the different scenarios, the WTP ranged from €10,600 to over a million. Wide confidence intervals abound. The authors’ findings only partially support an assumption of weak scope sensitivity – that more QALYs are worth paying more for – and do not at all support a strong assumption of scope sensitivity that WTP is proportional to QALY gain. This is what is known as scope bias, and this insensitivity to scope also applied to the variability in uncertainty. The authors also found that using different EQ-5D or VAS tariffs to estimate health state values resulted in variable differences in WTP estimates. Consistent relationships between individuals’ characteristics and their WTP were not found, though income and education seemed to be associated with higher willingness to pay across the sample. It isn’t clear what the implications of these findings are, except for the reinforcement of any scepticism you might have about the sociomathematical validity (yes, I’m sticking with that) of the QALY.

Credits

Cancer drugs and public preferences

Last year the UK government announced the establishment of a £600 million cancer drug fund, to be spent over 3 years. This represents a minuscule amount of money compared to the NHS’s annual budget, which is in excess of £100,000,000,000. However, it demonstrates the government’s preference for expenditure on the treatment of cancer over and above other terminal diseases such as multiple sclerosis (MS). Laura Weir of the MS Society recently spoke out in opposition to this special treatment of cancer. I tend to agree with her view, but am I justified?

Public preferences

In recent years an increasing number of newspaper column inches have been dedicated to criticising NICE for rejecting expensive cancer drugs because they are not deemed cost-effective. If we believe the media then the nation is in outrage about this. The prevailing ‘ideology’ in health economics is to evaluate interventions based on the extent to which they satisfy the preferences of the public. This is done by calculating the number of QALYs gained from an intervention and assigning a monetary value to this gain. The government has now implicitly increased this monetary value for cancer drugs, making them more likely to be deemed cost-effective. If we support the use of public preferences, and if the public support extra spending on cancer, then surely we must in turn also support the fund?

Preference for cancer drugs?

The question is whether society is willing to pay more for a drug that helps cancer patients than for a drug that improves or extends the life of anybody else. Is there really a public preference for spending on cancer drugs? I suspect there is, even if this preference has been reinforced and possibly created by the media. To my knowledge there has not been any significant research in this area. If such research did show a preference then it may justify an increased willingness to pay for cancer drugs.

And what about MS?

As somebody whose life has been affected by MS, but not by cancer, I may be bias. Or not. But I believe that expenditure on drugs should be based on the benefit they provide to an individual. Presumably the preference for cancer drugs, if not completely media-driven, is down to the large number of people affected by the disease. When it comes to the amount of money to be spent at an individual level it seems illogical to allow decisions about this to be guided by prevalence. Let’s remember we are not talking about research here, but the fact that an individual with cancer will be allowed to buy expensive (read: less cost-effective) drugs, while somebody with MS will not. I believe this is wrong. But then, I believe that the use of public preferences is not ideal.

Resources are scarce and for every expenditure there is an opportunity cost. An increase in our willingness to pay for the benefits of cancer drugs, at the extreme, leads to a decrease in spending on all other health care interventions. The cancer drug fund raises many questions, not least the possibility that a QALY may no longer be a QALY but may be a cancer-QALY. I believe this is dangerous territory.

Does this issue leave you questioning public preferences? Should we be prioritising treatment for cancer? Or is this all simply a fabrication by the media?

Paying for organs

We have recently seen the idea of buying/selling/trading organs thrust into the media spotlight (and not for the first time). There’s a lot of very poor thinking floating around in this debate, though Sue Rabbitt Roff’s recent paper, which helped fuel the flames of the new debate, is a little more useful.

A market for organs?

There are many reasons why Sue Rabbitt Roff does not propose this, and why Iran is the only country that has adopted one. Ethically the practice is, at best, dubious. At worst it is massively exploitative. Without enough regulation and administration to render it pointless, a market would be hugely inequitable and contradictory to most Western government policy; it would redistribute health from the poor to the rich. However, as heartless machines of rationality, economists tend to be more interested in what is the most efficient policy to adopt. Economists (such as Becker and Elias) have been weighing-in on this issue for a while. In their enjoyable free-marketeer rantings on the topic, the folks at Freakonomics seemingly raised ‘repugnance’ as the only argument against a market for organs. But hopefully readers of this blog are a little more informed when it comes to health economics and realise that a market for organs, like any free market healthcare system, will be massively inefficient. Market-failures (both the “this market doesn’t look how we want it to look” kind, as well as actual market failure) would abound. While the rich’s willingness to pay for organs would far exceed that of the poor, most of us would accept that their capacity to benefit from organ donation would be the same (or lower) than that of the poor. Because the rich assign a higher monetary value to their health it would be possible for there to be a net loss of health from the purchase of an organ. In a free market system organs would, presumably, go to those who can afford them (the rich), rather than those who stand to gain the most from receiving them (the sick). And we all know that the richest are rarely the sickest. To me, none of this sounds very efficient.

Another way?

In the UK the idea of a free market for health care is repugnant enough; thankfully there is little chance of a market for organs developing. However, Sue Rabbitt Roff’s paper does not suggest this. This BMJ article doesn’t really say much and is quite limited. Economists should be chomping at the bit with claims like:

“…if the standard payment [for a kidney] were equivalent to the average annual income in the UK, currently about £28000, it would be an incentive across most income levels for those who wanted to do a kind deed and make enough money to, for instance, pay off university loans.”

Rubbish. But that doesn’t matter. Her general idea – a heavily-regulated system of organ purchase by the NHS -is a feasible one. Let’s remember that here we are talking about anonymous donors and recipients – family and friend donations could remain as they are. To be equitable there could be a fixed payment from the NHS to a donor. The level of this payment should be equal to (society’s valuation of) the health gain enjoyed by the individual receiving the transplant. In a world of value-based pricing this would be the norm! A second requirement would be that the price should be greater than or equal to the loss of health-related quality of life (plus other associated costs) to the donor. This would mean that a donation could be prevented if deemed exploitative, even if against the wishes of the donor. Such a system could nicely boost the supply of organs to existing (need-based) waiting lists.

This will probably be piloted in Scotland: the land of new ideas. For me a system would have to be so heavily regulated that there would not be much point. Politicians, clinicians and academics would love a quick-fix for the problem of organ shortages, but they’ll just have to work a bit harder. People can be encouraged to donate organs in other ways; a switch from opt-in to opt-out posthumous donation being an excellent start.

What do you think? Could the sale and purchase of organs be efficient and equitable? What safeguards would need to be in place if a system was introduced?