Medical consultation models focus on the patient’s agenda. But what about what doctor’s ideas, concerns and expectations! Shouldn’t we look at the agenda of all the players involved?
Learning objectives
1. Consider the use of game theory as a framework on which to model the doctor-patient encounter
2. Clarifying your own agenda as an influencing factor on the medical consultation
3. Reflecting on the limitations of single encounter consultation models
New doctors or specialist trainees are often asked by patients whether they are a permanent addition to the practice or a locum.
Questions
From the perspective of a patient, what is there to be gained from seeing the same clinician?
Now from the perspective of a doctor, what can you gain from seeing the same patient?
What are the shared advantages (for both patients and doctors) in continuity of care?
Are there any disadvantages?
Game theory is a branch of applied mathematics, notably used in economics (to understand the behaviours of firms, markets, and consumers). It attempts to mathematically capture behaviour in strategic situations, in which an individual’s success in making choices depends on the choices of others. It has also been used in politics to study to what extent people with different preferences can work together and whether they will take risks to achieve a cooperative outcome.
The use of game theory in medicine has been limited, or at least unspoken. Perhaps this is because the doctor-patient relationship has often been perceived as unidirectional; a patient breaks a bone, the doctor fixes it, game over. However, modern medicine has redefined the patient and indeed illness. Doctors are increasingly involved in the prevention of disease in asymptomatic patients. Various options and incentives are available to patient and doctor. The consultation can be seen as an exercise between the patient and the doctor in gaining information from each other. Decisions are based on which information is disclosed and how it is presented.
Consider the differences between consulting an acute problem (e.g. sore throat) and a chronic disease (e.g. hypertension).
Questions
What outcomes might a patient want from the encounter?
Are the outcomes different for the doctor?
At the risk of oversimplification, in an acute problem scenario, the goal for the patient may just be feeling better as soon as possible. In the chronic disease scenario the situation for the patient may be more complex: maintenance of health (or slowing further decline), the hassle/stigma of taking medication, cost of prescriptions, attending appointments for reviews/blood tests, plus other issues which may be unique to that particular individual.
The doctor is the player who is often overlooked. In game theory, it would be more than naive to act purely altruistically; it wouldn’t be rational. Self-interest is considered the pivotal factor which, in the context of healthcare, may appear alien. Some things you might have considered from the perspective of a doctor are the resolution or prevention of illness, managing future workload, professional satisfaction, time constraints, resource management and financial renumeration/incentives (e.g. the Quality and Outcomes Framework/QOF).
This is where things get even more interesting. Whereas managing a sore throat may be managed with a single consultation, chronic disease management requires repeated interactions between patient and doctor to achieve their goals. Repeated interactions or consultations are the mainstay of primary care chronic disease management, so why do consultation models usually focus on single encounter scenarios? In game theory life is more complex but self-interest you can be sure of.
The stag hunt is a game which models a conflict between safety and social cooperation. In this game two hunters decide to go on a hunt. Each player must choose an action without knowing the choice of the other. Each can individually choose to hunt a stag or hunt a hare. If an individual hunts a stag, they must have the cooperation of their partner in order to succeed. An individual can get a hare by themselves, but a hare is worth less than a stag. Two equilibria can be reached:
1. Risk dominant – If there is uncertainty about what the other hunter will do, players are more likely to hunt hares.
2. Payoff dominant – If both hunters could agree in advance then the stag is preferential as it reaps the most rewards for both.
Questions
Can you think of examples where the doctor and patient are involved in such a stag hunt?
Does it matter if the patient is managed by a different doctor each time they visit for their chronic disease review?
Continuity of care is an important factor for both doctor and patient in understanding how the other is predicted to behave. Repeated interactions along with the expectation of an indefinite number of future interactions may enable the establishment of trust and act to reinforce mutual cooperation, potentially leading to mutually beneficial payoff dominant outcome (the stag). Conversely, if continuity is lacking or if previous interactions have been poor for either party, this experience will lead them to adopt a more risk dominant strategy (the hare).
This has implications for different aspects of primary care. From an educational standpoint, exams such as the Clinical Skills Assessment (CSA) or similar single encounter patient simulations do not represent routine UK general practice where the candidate will have already formed relationships (good and bad) with patients. The simulated patient experience is more akin to out-of hours encounters or the experience of a short-term locum GP. I would like to stress however, this post is intended in no way to denigrate this type of work nor the simulated patient examination per se. Instead I hope to increase awareness of the fact that there are real difference between the work of GPs in different settings and that this should be recognised by both patients and doctors. These differences lead to modification of clinician behaviour in terms of strategy and risk thresholds.
Some doctors are resigned to the variable nature of their work and say that instead of continuity of care they rely on ‘continuity of record’ (the medical notes being the source of knowledge regarding the previous encounters with the patient who may now be seen by various clinicians in different settings).
Questions
Does the medical record convey all the information required for doctors and patients to immediately adopt a payoff dominant strategy on first encounter?
How is the consultation different when a doctor encounters a patient outside the the traditional general practice setting (e.g. out-of hours, walk-in-centres)?
If a doctor never expects to see a particular patient again, would you be surprised if they practised defensive medicine, had higher indemnity fees and worse outcomes?
There is a lot more to how game theory can provide a perspective on medicine. Please add your thoughts in the comments section below. I recognise that this post may represent a starting position for many readers and I hope to cover the issue in more depth in the future.
Summary
Medicine is changing and prevention of disease is increasingly an important aspect of providing care. In game theory both patient and doctor can be conceptualised as players in a game who develop strategies in order to get what they feel is the best outcome for themselves. Repeated interactions between the same doctor and patient provides knowledge and experience about the other. If used, this in turn helps predict future behaviour, trust and better outcomes.
Further resources
Playing doctor: application of game theory to medical decision-making
https://www.ncbi.nlm.nih.gov/pubmed/3734022
Medical ethics, logic traps, and game theory: an illustrative tale of brain death
https://www.ncbi.nlm.nih.gov/pubmed/15289519
Game theory and strategy in medical training
https://www.ncbi.nlm.nih.gov/pubmed/27762022
UNEXAMINED MEDICINE 
Another interesting paper I recently found on this subject: A game theoretic approach to repeated foreign body ingestion (https://www.researchgate.net/publication/273501086_A_game_theoretic_approach_to_repeated_foreign_body_ingestion)
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