Thesis Thursday: Alastair Irvine

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 Alastair Irvine who has a PhD from the University of Aberdeen. If you would like to suggest a candidate for an upcoming Thesis Thursday, get in touch.

Title
Time preferences and the patient-doctor interaction
Supervisors
Marjon van der Pol, Euan Phimister
Repository link
http://digitool.abdn.ac.uk/webclient/DeliveryManager?pid=238373

How can people’s time preferences affect the way they use health care?

Time preferences are a way of thinking about how people choose between things that happen over time. Some people prefer a treatment with large side effects and a long chain of future benefits; others prefer smaller benefits but less side effects. These influence a wide range of health outcomes and decisions. One of the most interesting questions I had coming into the PhD was around non-adherence.

Non-adherence can’t be captured by ‘standard’ exponential time preferences because there is no way for something you prefer now to be ‘less preferred’ in the future if everything is held constant. Instead, present-bias preferences can capture non-adherent behaviour. With these preferences, people place a higher weight on the ‘current period’ relative to all future periods but weight all future periods consistently. What that means is you can have a situation where you plan to do something – eat healthily, take your medication – but end up not doing it. When planning, you placed less relative weight on the near term ‘cost’ (like medication side effects) than you do when the decision arrives.

In what way might the patient-doctor interaction affect a patient’s adherence to treatment?

There’s asymmetric information between doctors and patient, leading to an agency relationship. Doctors in general know more about treatment options than patients, and don’t know their patient’s preferences. So if doctors are making recommendations to patients, this asymmetry can lead to recommendations that are accepted by the patient but not adhered to. For example, present-biased patients accept the same treatments as exponential discounters. Depending on the treatment parameters, present-biased people will not adhere to some treatments. If the doctor doesn’t anticipate this when making recommendations, it leads to non-adherence.

One of the issues from a contracting perspective is that naive present-bias people don’t anticipate their own non-adherence, so we can’t write traditional ‘separating contracts’ that lead present-bias people to one treatment and exponential discounters to another. However, if the doctor can offer a lower level of treatment to all patients – one that has less side effects and a concomitantly lower benefit – then everyone sticks to that treatment. This clearly comes at the expense of the exponential discounters’ health, but if the proportion of present-bias is high enough it can be an efficient outcome.

Were you able to compare the time preferences of patients and of doctors?

Not this time! It had been the ‘grand plan’ at the start of the PhD to compare matched doctor and patient time preferences then link it to treatment choices but that was far too ambitious for the time, and there had been very little work establishing how time preferences work in the patient-doctor interaction so I felt we had a lot to do.

One interesting question we did ask was whether doctors’ time preferences for themselves were the same as for their patients. A lot of the existing evidence asks doctors for their own time preferences, but surely the important time preference is the one they apply to their patients?

We found that while there was little difference between these professional and private time preferences, a lot of the responses displayed increasing impatience. This means that as the start of treatment gets pushed further into the future, doctors started to prefer shorter-but-sooner benefits for themselves and their patients. We’re still thinking about whether this reflects that in the real world (outside the survey) doctors already account for the time patients have spent with symptoms when assessing how quickly a treatment benefit should arrive.

How could doctors alter their practice to reduce non-adherence?

We really only have two options – to make ‘the right thing’ easier or the ‘wrong thing’ more costly. The implication of present-bias is you need to use less intense treatments because the problem is the (relative) over-weighting of the side effects. The important thing we need for that is good information on adherence.

We could pay people to adhere to treatment. However, my gut feeling is that payments are hard to implement on the patient side without being coercive (e.g making non-adherence costly with charges) or expensive for the implementer when identification of completion is tricky (giving bonuses to doctors based on patient health outcomes). So doctors can reduce non-adherence by anticipating it, and offering less ‘painful’ treatments.

It’s important to say I was only looking at one kind of non-adherence. If patients have bad experiences then whatever we do shouldn’t keep them taking a treatment they don’t want. However, the fact that stopping treatment is always an option for the patient makes non-adherence hard to address because as an economist you would like to separate different reasons for stopping. This is a difficulty for analysing non-adherence as a problem of temptation. In temptation preferences we would like to change the outcome set so that ‘no treatment’ is not a tempting choice, but there are real ethical and practical difficulties with that.

To what extent did the evidence generated by your research support theoretical predictions?

I designed a lab experiment that put students in the role of the doctor with patients that may or may not be present-biased. The participants had to recommend treatments to a series of hypothetical patients and was set up so that adapting to non-adherence with less intense treatments was best. Participants got feedback on their previous patients, to learn about which treatments patients stuck to over the rounds.

We paid one arm a salary, and another a ‘performance payment’. The latter only got paid when patients stuck to treatment and the pay correlated with the patient outcomes. In both arms, patients’ outcomes were reflected with a charity donation.

The main result is that there was a lot of adaptation to non-adherence in both arms. The adaptation was stronger under the performance payment, reflecting the upper limit of the adaptation we can expect because it perfectly aligns patient and doctor preferences.

In the experimental setting, even when there is no direct financial benefit of doing so, participants adapted to non-adherence in the way I predicted.

Chris Sampson’s journal round-up for 31st December 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.

Perspectives of patients with cancer on the quality-adjusted life year as a measure of value in healthcare. Value in Health Published 29th December 2018

Patients should have the opportunity to understand how decisions are made about which treatments they are and are not allowed to use, given their coverage. This study reports on a survey of cancer patients and survivors, with the aim of identifying patients’ awareness, understanding, and opinions about the QALY as a measure of value.

Participants were recruited from a (presumably US-based) patient advocacy group and 774 mostly well-educated, mostly white, mostly women responded. The online survey asked about cancer status and included a couple of measures of health literacy. Fewer than 7% of participants had ever heard of the QALY – more likely for those with greater health literacy. The survey explained the QALY to the participants and then asked if the concept of the QALY makes sense. Around half said it did and 24% thought that it was a good way to measure value in health care. The researchers report a variety of ‘significant’ differences in tendencies to understand or support the use of QALYs, but I’m not convinced that they’re meaningful because the differences aren’t big and the samples are relatively small.

At the end of the survey, respondents were asked to provide opinions on QALYs and value in health care. 165 people provided responses and these were coded and analysed qualitatively. The researchers identified three themes from this one free-text question: i) measuring value, ii) opinions on QALY, and iii) value in health care and decision making. I’m not sure that they’re meaningful themes that help us to understand patients’ views on QALYs. A significant proportion of respondents rejected the idea of using numbers to quantify value in health care. On the other hand, some suggested that the QALY could be a useful decision aid for patients. There was opposition to ‘external decision makers’ having any involvement in health care decision making. Unless you’re paying for all of your care out of pocket, that’s tough luck. But the most obvious finding from the qualitative analysis is that respondents didn’t understand what QALYs were for. That’s partly because health economists in general need to be better at communicating concepts like the QALY. But I think it’s also in large part because the authors failed to provide a clear explanation. They didn’t even use my lovely Wikipedia graphic. Many of the points made by respondents are entirely irrelevant to the appropriateness of QALYs as they’re used (or in the case of the US, aren’t yet used) in practice. For example, several discussed the use of QALYs in clinical decision making. Patients think that they should maintain autonomy, which is fair enough but has nothing to do with how QALYs are used to assess health technologies.

QALYs are built on the idea of trade-offs. They measure the trade-off between life extension and life improvement. They are used to guide trade-offs between different treatments for different people. But the researchers didn’t explain how or why QALYs are used to make trade-offs, so the elicited views aren’t well-informed.

Measuring multivariate risk preferences in the health domain. Journal of Health Economics Published 27th December 2018

Health preferences research is now a substantial field in itself. But there’s still a lot of work left to be done on understanding risk preferences with respect to health. Gradually, we’re coming round to the idea that people tend to be risk-averse. But risk preferences aren’t (necessarily) so simple. Recent research has proposed that ‘higher order’ preferences such as prudence and temperance play a role. A person exhibiting univariate prudence for longevity would be better able to cope with risk if they are going to live longer. Univariate temperance is characterised by a preference for prospects that disaggregate risk across different possible outcomes. Risk preferences can also be multivariate – across health and wealth, for example – determining the relationship between univariate risk preferences and other attributes. These include correlation aversion, cross-prudence, and cross-temperance. Many articles from the Arthur Attema camp demand a great deal of background knowledge. This paper isn’t an exception, but it does provide a very clear and intuitive description of the various kinds of uni- and multivariate risk preferences that the researchers are considering.

For this study, an experiment was conducted with 98 people, who were asked to make 69 choices, corresponding to 3 choices about each risk preference trait being tested, for both gains and losses. Participants were told that they had €240,000 in wealth and 40 years of life to play with. The number of times that an individual made choices in line with a particular trait was used as an indicator of their strength of preference.

For gains, risk aversion was common for both wealth and longevity, and prudence was a common trait. There was no clear tendency towards temperance. For losses, risk aversion and prudence tended to neutrality. For multivariate risk preferences, a majority of people were correlation averse for gains and correlation seeking for losses. For gains, 76% of choices were compatible with correlation aversion, suggesting that people prefer to disaggregate fixed wealth and health gains. For losses, the opposite was true in 68% of choices. There was evidence for cross-prudence in wealth gains but not longevity gains, suggesting that people prefer health risk if they have higher wealth. For losses, the researchers observed cross-prudence and cross-temperance neutrality. The authors go on to explore associations between different traits.

A key contribution is in understanding how risk preferences differ in the health domain as compared with the monetary domain (which is what most economists study). Conveniently, there are a lot of similarities between risk preferences in the two domains, suggesting that health economists can learn from the wider economics literature. Risk aversion and prudence seem to apply to longevity as well as monetary gains, with a shift to neutrality in losses. The potential implications of these findings are far-reaching, but this is just a small experimental study. More research needed (and anticipated).

Prospective payment systems and discretionary coding—evidence from English mental health providers. Health Economics [PubMed] Published 27th December 2018

If you’ve conducted an economic evaluation in the context of mental health care in England, you’ll have come across mental health care clusters. Patients undergoing mental health care are allocated to one of 20 clusters, classed as either ‘psychotic’, ‘non-psychotic’, or ‘organic’, which forms the basis of an episodic payment model. In 2013/14, these episodes were associated with an average cost of between £975 and £9,354 per day. Doctors determine the clusters and the clusters determine reimbursement. Perverse incentives abound. Or do they?

This study builds on the fact that patients are allocated by clinical teams with guidance from the algorithm-based Mental Health Clustering Tool (MHCT). Clinical teams might exhibit upcoding, whereby patients are allocated to clusters that attract a higher price than that recommended by the MHCT. Data were analysed for 148,471 patients from the Mental Health Services Data Set for 2011-2015. For each patient, their allocated cluster is known, along with a variety of socioeconomic indicators and the HoNoS and SARN instruments, which go into the MHCT algorithm. Mixed-effects logistic regression was used to look at whether individual patients were or were not allocated to the cluster recommended as ‘best fit’ by the MHCT, controlling for patient and provider characteristics. Further to this, multilevel multinomial logit models were used to categorise decisions that don’t match the MHCT as either under- or overcoding.

Average agreement across clusters between the MHCT and clinicians was 36%. In most cases, patients were allocated to a cluster either one step higher or one step lower in terms of the level of need, and there isn’t an obvious tendency to overcode. The authors are able to identify a few ways in which observable provider and patient characteristics influence the tendency to under- or over-cluster patients. For example, providers with higher activity are less likely to deviate from the MHCT best fit recommendation. However, the dominant finding – identified by using median odds ratios for the probability of a mismatch between two random providers – seems to be that unobserved heterogeneity determines variation in behaviour.

The study provides clues about the ways in which providers could manipulate coding to their advantage and identifies the need for further data collection for a proper assessment. But reimbursement wasn’t linked to clustering during the time period of the study, so it remains to be seen how clinicians actually respond to these potentially perverse incentives.

Credits

Journal Club Briefing: Dolan and Kahneman (2008)

Today’s Journal Club Briefing comes from the Academic Unit of Health Economics at the University of Leeds. At their journal club on 2nd August 2017, they discussed Dolan and Kahneman’s 2008 article from The Economic Journal: ‘Interpretations of utility and their implications for the valuation of health‘. If you’ve discussed an article at a recent journal club meeting at your own institution and would like to write a briefing for the blog, get in touch.

Why this paper?

Dolan and Kahneman (2008) is a paper which was published nearly ten years ago, was written several years before that, and was not published in a health-related journal. It’s hence, at first sight, a slightly curious choice for a health economics journal club. However, it raises issues which are at the heart of health economics practice. The questions raised by this article have not as yet been answered, and don’t look likely to be answered anytime soon.

Summary

Experienced vs. decision utility

The article’s point of departure is the distinction between experienced utility and decision utility, often a source of fruitful research in behavioural economics. Experienced utility is utility in the Benthamite sense, meaning the hedonic experience in the current moment: the pleasure and/or pain felt by a person at any given point in time. Decision utility is utility as taught in undergraduate economics textbooks: an objective function which the individual dispassionately acts to maximise. In the neoclassical framework of said undergraduate textbooks, this is a distinction without a difference. The individual correctly forecasts the expected flow of experienced utility given the available information and her actions, forms a decision utility function from it and acts to maximise it.

However, Thaler and Sunstein wouldn’t have sold as many books if things were so simple. Many systematic and significant instances of divergences between experienced and decision utility have been well documented, and several people (including one of the authors of this paper) have won Nobel prizes for it. The one which this article focuses on is adaptation.

Adaptation

The authors summarise a large body of evidence that shows that individuals suffer a large loss of utility after a traumatic event (e.g. the loss of a limb or loss of function), but that for many conditions they will adapt to their new situation and recover much of their utility loss. After as little as a year, their valuation of their health is very similar to that of the general population. Furthermore, the authors precis various studies which show that individuals routinely underestimate drastically the amount of adaptation that would occur should such a traumatic event befall them.

This improvement over time in the health-related utility experienced by people with many conditions is partly due to hedonic adaptation – the internal scale of pleasure/pain re-calibrates to their new situation – and partly due to behavioural change, such as finding new pastimes to replace those ruled out by their condition. While the causes of adaptation are fascinating, the focus here is not on the mechanisms behind it, but rather on the consequences for measuring utility and the implications for resource allocation.

Health valuation and adaptation

The methods health economists use to evaluate the utility of being in a given health state, such as time trade-off, standard gamble or discrete choice experiments, will tend to elicit decision utility. They are based on choices between hypothetical states and so will not capture the changes in experienced utility due to adaptation. Thus valuations of health states from the general public will tend to be lower than the valuations from people actually living in the health state.

At first glance, the consequences for resource allocation may not appear to be particularly severe. It may lead to more resources being devoted to healthcare as a whole (at least for life-improving treatments – life-extending treatments are a different case), but the overall healthcare budget is in practice largely a political decision. However, it will not lead to distortions between treatments for alternative conditions.

Yet adaptation is not a universal phenomenon. There are conditions for which little or no adaptation is seen (for example unexplained pain), and when it occurs, it occurs at different speeds and to differing extents for different conditions. The authors show that valuations of conditions with a greater initial utility loss are lower than conditions with a lesser initial loss but a lower degree of adaptation, and thus will receive a greater level of resources, despite the sum of experienced utility being the same for both. The authors argue that this is unfair, and that health economists should update their practices to better capture experienced utility.

Public vs. patient preference

A common argument in favour of the status quo is that (in many countries at least) it is public resources which are being allocated, and thus it is public preferences which should be respected. It appears legitimate to allocate resources to assuage public fears of health states, even if those health states are worse in their imagination than in reality. The authors consider this argument and reply that, in this case, the instruments of health economists are still not fit for purpose. General measures of health states, such as EQ-5D, go out of their way to describe states in abstract terms and to separate them from causes, such as cancer, which may carry an emotional affect. It cannot be argued that public valuations are justified because resources should be allocated according to public fears if the measurement of valuation deliberately tries not to elicit those fears.

The argument that adaptation causes serious problems for valuing health and for allocation of health resources is a persuasive one. It is undoubtedly true that changes in utility over time, and other violations of the neoclassical economic paradigm such as reference dependence, do not presently receive sufficient attention in health economics and policy decisions in general.

Discussion

Which yardstick?

Despite the stimulating discussion and the overall brilliance of the paper, there are some elements which can be challenged. One of them is that throughout, the authors’ arguments and recommendations are made from the standpoint that the sum over time of the flow of experienced utility from a health state is to be used as the sole measure of value. This would consist in what one of the authors calls the day reconstruction method (DRM) which consists in rating a range of feelings including happiness, worry, and frustration.

Despite the acknowledgement of some philosophical difficulties, the sum of the flow of experienced utility is treated as if it is the only true yardstick with which to measure health, without a convincing justification and no discussion on the qualitative aspect of the measurement as opposed to a truly cardinal measure of health allowing ranking of individuals’ health states.

Public vs. private preferences revisited

The authors raise the question of whether current practice can be justified by a desire to soothe public fears, and dismiss it since the elicitation tools are not suitable. However, they do not address the question of whether allocating public resources according to the public’s (incorrect) fears of given diseases or health states could be a legitimate health policy aim. One could imagine, for example, a discrete choice experiment eliciting how much the general public dreads cancer over other diseases, and make an argument that the welfare of the public is improved by allocating resources based on these results. There are myriad problems with such an approach, of course, but there seem to be no fewer problems with alternative approaches.

Intertemporal welfare

Intertemporal welfare judgements are notoriously difficult once the exponential discounting framework is left. It seems just as legitimate to base valuations on the ex post judgement of individuals who have fully adjusted to a health state as on an integration of past feelings, most of which are now distant memories. Most people would agree that the time to value their experience of a marathon is after completing it, not during the twenty-fifth mile or at the start line.

Indeed, this appears to be the position tacitly taken elsewhere by Kahneman in his work on the peak-end rule. In Redelmeier et al. (2003), it was found that the retrospective rating of the pain of a colonoscopy was based almost exclusively on the peak intensity of pain and on the pain felt at the end. Thus procedures which were extended by an extra three minutes were remembered as less painful than standard procedures, even though the total pain experienced was greater. Furthermore, those who underwent the extended procedure were more likely to state they would undergo it again. It would seem strange, in this case, to judge them as worse off.

Schelling (1984) ends his superlative discussion of the problems of intertemporal decision making with the following thought experiment. Just as with valuing health, there are no easy answers.

[S]ome anesthetics block transmission of the nervous impulses that constitute pain; others have the characteristic that the patient responds to the pain as if feeling it fully but has utterly no recollection afterwards. One of these is sodium pentothal. In my imaginary experiment we wish to distinguish the effects of the drug from the effects of the unremembered pain, and we want a healthy control subject in parallel with some painful operations that will be performed with the help of this drug. For a handsome fee you will be knocked out for an hour or two, allowed to sleep it off, then tested before you go home. You do this regularly, and one afternoon you walk into the lab a little early and find the experimenters viewing some videotape. On the screen is an experimental subject writhing, and though the audio is turned down the shrieks are unmistakably those of a person in pain. When the pain stops the victim pleads, “Don’t ever do that again. Please.”

The person is you.

Do you care?

Do you walk into your booth, lie on the couch, and hold out your arm for today’s injection?

Should I let you?

Credits