AT some point in their career most doctors will be asked by one of their patients:

“Well doc, how long have I got?”

This is a question that has many possible underlying meanings for the patient, and any numerical answer is almost certain to be wrong. Generally, we can best help the patient by exploring the reasons it was asked and providing an answer that includes discussion of the uncertainties.

However, the varying legislative requirements in each state for access to voluntary assisted dying (VAD) seem to imply a certainty that does not easily match up with the intrinsic unknowns and complexity of life-ending illnesses.

It almost goes without saying that all doctors should already have considered, or be considering, how they will respond, given that all six Australian states have either already made VAD available or have passed legislation that will make VAD legal before the end of 2023. And, with legislation to revoke the Euthanasia Laws Act 1997 having been introduced recently to the Australian Parliament, it seems likely that the Australian Capital Territory and the Northern Territory will soon create their own legislation on VAD.

While some doctors (eg, oncologists and palliative care specialists) are more likely to face requests from their patients for VAD, any doctor or other health worker may find themselves engaged in a conversation about VAD with a patient, a family member or a friend. The patient may simply be curious, seeking information or a better understanding of the reasons people might consider VAD and the grounds on which it may be granted. Others will be seriously considering VAD and wishing to talk with someone they trust who can support them in their exploration of complex medical, emotional and spiritual issues.

Perhaps the most important thing that every doctor can do up front is to reflect on their own position on VAD – its origins in their beliefs and their personal and professional experiences. Having done so, doctors will be in better a position to decide the extent to which they are, or are not, willing to participate in an activity for which legislation creates a range of rights and responsibilities for both doctors and their patients. To that end, doctors should visit their state (or perhaps, in the future, territory) health department website for full details, and if appropriate engage in the training that is required.

Those who are willing to actively support patients pursuing VAD will need to follow the stepwise processes that have been designed for its implementation.

Those with conscientious objections to VAD will need to understand their own rights and obligations and respect the rights of their patients under the VAD legislation in their state or territory.

VAD legislation in every state includes the requirement that the doctors who are assessing a patient’s eligibility for VAD make a prediction about their patient’s life-expectancy – whether it does or does not exceed either 6 or 12 months, depending on the state and the patient’s illness.

Easy to legislate, but not so easy to quantify accurately for any one patient.

Doctors use their training and experience (accumulated wisdom) to generate information that their patient can use to understand the nature of their disease and the impact it may have on the quality and quantity of their life, and to decide how they would prefer to respond to that knowledge, including its uncertainties.

In my experience, most wise doctors qualify the certainty of their diagnosis and prognosis by including a description of alternative scenarios, exploring unknowns and unknowables, and expressing appropriately honest uncertainty about how an illness will progress and the quantification of life-expectancy.

Modern medicine has increased the diversity of possible outcomes but has not made predicting the life expectancy of an individual any easier. A doctor’s assessment is complemented by pooled data collection from large cohorts of similarly afflicted individuals that offers probability-based prognostication about the outcomes – Kaplan–Meyer graphs, survival distribution curves, and worst-, median- and best-case scenarios. Doctors inject their personal hopes and biases about the treatments they can now offer into what they communicate to their patients, and these can become the patient’s expectations. And, also being human, some patients seem to hear only those parts of predictions that they would like to experience,

Many a patient has said that,

“The doctor gave me 5 years.”

when the doctor actually said

“Patients with your condition can survive from few months to up to 5 years, if the treatment works really well.”

Patients are referred to us in palliative care because someone – they, their family, or their treating doctor – has recognised that they are likely to die or are dying from their illness. Rather than predicting the duration of life other than in broad terms, we usually focus on the quality of life that might be achievable. We are also wary of describing how a patient will die because, even with the same disease, individual experiences of dying vary greatly.

Early in my palliative medicine career I had one patient who had been told in July that he wouldn’t live beyond Christmas. One year later, he and his family were still waiting. Christmas had come and gone, and while this might have been interpreted as a positive, they (including the patient) were all distressed by the uncertainty of their lives being on hold and with no understanding of when his life might end.

Doctors make predictions about life expectancy by considering what we know about how our patient’s disease is progressing, the likely natural history of their disease, their other illnesses and frailties, our assessment of their individual robustness at the macroscopic level of their bodily functions (pulse, blood pressure, respiration, urine output, cognition) and their capacity to engage in the activities of daily living and social interaction, and perhaps augmented by some quantitative measure of their physiology. Then (perhaps metaphorically) we create an imaginary graph in our head and draw an imaginary downwards trajectory line that intersects with an imaginary baseline beyond which we imagine (based on our prior experience) that it would not be possible for the patient to remain alive.

But dying is not a linear process. Sometimes a patient’s functional decline line can plateau for quite some time. More often, a seemingly steady deterioration suddenly accelerates (like a stock market collapse) when some essential physiological activity suddenly and unpredictably unravels, triggering a massive functional decline, and the patient dies sooner than expected, but not unexpectedly. As with all complex systems that are becoming unstable (here and here), it is not possible to predict the timing of (and often we do not know the immediate reason for) the final collapse of the functional organisation of a dying person’s body. Some dying people, such as Queen Elizabeth II, just slow down and glide to a halt for no identified reason (wisely, nobody looks for one), dying peacefully of “old age”, perhaps suddenly but to nobody’s surprise.

I eventually settled on expressing my predictions of life expectancy in terms of hours to days, days to weeks, weeks to months, or months to years, occasionally qualified with “the short end of” or “the long end of”. I stopped putting a number in front of any prediction of life expectancy because that would focus attention on a date in the future that would most often be wrong. And I always included a discussion of the uncertainty of prediction and my hopes that the patient and their family would be able to focus on the pursuit of quality, those things that were important to them, for the remainder of the person’s life, and described that approach as a perspective on life that can help us to live with dying.

On one ward round, I left the patient’s room having told their family that I thought that their relative would not die that day. As I was washing my hands before moving on to the next patient, one of them they came out to tell me that the patient had died. They had been well prepared for the person’s death and were amused by my inaccuracy.

Another patient was transferred to our palliative care ward to die because their bowel was massively infarcted. I suggested a life expectancy of a few days but he slowly regained his appetite and eventually walked out of the ward.

It also seems that we are not without influence over the timing of our death. Most palliative care workers will have seen patients who defy expectations and hang on for several days until someone has arrived from far away, have a conversation with them, and then die. Others seem stable but, like one very old person faced with the loneliness of yet another residential aged care lockdown for COVID-19, summon their relatives to say farewell and die soon thereafter.

Nonetheless, skilled clinicians are pretty good at reading the subtle physical and behavioural changes of impending death in those close to dying from an inexorably progressive illness, and will have few doubts about fulfilling the requirements of VAD legislation with confident predictions, even knowing that some of these patients will plateau and survive way beyond what we might have thought possible.

On the other hand, months to years is a much bigger window than hours to days or weeks. Even if we have a good understanding of the pathophysiology of patients with life-limiting illnesses who are not obviously nearing their death, the unpredictable and unknown variables (eg, cancer secondaries, narrow blood vessels, failing nephrons and neurones) bring with them a much broader range of possible pathways to the end of a patient’s life, including depending on whether or not they wish to pursue potentially life-prolonging treatment.

This is not dissimilar to the Bureau of Meteorology’s predictions for the path of a cyclone – reasonably certain where it will be tomorrow but subject to frequent revision and with a diversity of possibilities that increases the further they predict into the future.

So, with all of this uncertainty, how can we provide realistic and meaningful assessments of life expectancy that meet the requirements of VAD legislation?

Certainly, I would be reluctant to guarantee absolutely that any particular person will be dead in a certain time period, particularly when they are not in or approaching what seems to the terminal phase of their life with a known progressive illness, any more than I can guarantee that I myself will be alive. In a recent MJA article, Voluntary assisted dying: estimating life expectancy to determine eligibility, Nahm and colleagues explore the complexities of predicting the life expectancy of individuals in a manner that meets the requirements of the law. Other work over the years has similarly explored the inaccuracy and biases of doctor’s predictions of the life expectancy of individual patients.

One option is to make probabilistic predictions based on data and the sum of our experience and, as described (but not advocated) by Nahm and colleagues, accepting a statistical likelihood range around our subjective mean or median predictions of life expectancy for individual patient survival.

As an alternative, or perhaps as a complementary confirmatory activity, the assessing doctor might pose themselves a modified “surprise question” (here and here), used to encourage timely Advance Care Planning and referral to palliative care:

“Would I be surprised if this patient requesting access to VAD was dead in 6 months [one year if they have a neurological condition or are resident in Queensland] and if they had not completed the VAD process]?”

If the answer to this question is,

“No, I would not be surprised.”

then it would seem reasonable to say that the patient’s life expectancy is less than the legally required period.

If the answer is,

“Yes, I would be surprised.”

the doctor will have a bit more thinking to do, and may have to wait until they have a better sense that their patient is deteriorating.

However, doctors should not tie themselves in knots in the belief that they should or can provide an accurate quantification of life expectancy. VAD legislation simply requires doctors to make honest statements in good faith about what they expect would be to likely happen if their patient’s life is not shortened by VAD. The reality of such predictions is that it is simply impossible to know with certainty how much longer a complex system like a human can continue to function, but someone has to make the call.

Dr Will Cairns has retired from clinical practice as a palliative medicine specialist.



The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.

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2 thoughts on “Life expectancy: questions to ask yourself

  1. Chris Davis says:

    As Will knows, old age is not a disease nor a cause of death but instead an association, so to say Her Majesty the late Monarch died of old age is a reflection of the uncertainty that his article addresses. Keen monarch watchers may be aware that her doctors reportedly advised Her Majesty to cease her moderate intake of Dubonnet prior to her passing. Based on my experience of the therapeutic benefit of a little aperitif in the elderly, one can only speculate as to wisdom of that advice in the context of the outcome.

  2. Harley Powell says:

    The legal requirement for doctors to estimate an expectation of life of less than 6 months is to exclude patients with non-terminal illnesses from VAD, and is not to require doctors to accurately predict a date of death. The doctor’s estimate of probable life expectancy is sufficient to satisfy the legal requirement for eligibility for VAD.

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