In the US, it appears, life is not complete without an advance directive. Recent research from the University of Michigan shows that record numbers of Americans are completing the documents, which specify what types of treatment a person would like to receive - or prefer not to - if they become unable to make such decisions for themselves.
Between 2000 and 2010, the proportion of people with advance directives rose from 47 to 72 per cent, according to a study of more than 6,100 Americans aged 60 and older who died in that period. The results were published in the April issue of the Journal of the American Geriatrics Society.
One of the main reasons for advance directives' immense popularity in the US is the Patient Self-Determination Act, introduced in 1990, which requires a wide range of health care institutions to provide information about them to patients on admittance.
In Hong Kong there has only been a tiny trickle of the documents, and hardly anyone has even heard of them.
But with an ageing population and end-of-life health care costs spiralling as we get better at staying alive - but not necessarily at improving our quality of life - their use is likely to grow. A legal framework governing their use in Hong Kong is already a matter of lively debate.
Also known as living wills and advance decisions, advance directives were proposed in the US in 1969 to ensure that terminally ill people's wishes are respected; to give them the choice to opt out of treatment if the prognosis is particularly bad.
According to a 2010 study published in the New England Journal of Medicine, 30 per cent of people who need to make these sorts of decisions towards the end of their lives are not in a fit state to do so. One option is to appoint a surrogate to make the decisions for you, but patients can also choose to mention specific treatments they don't want to receive, or talk more generally in terms of preferred outcomes.
Hong Kong has a robust public health care system and patients rarely face the sort of ruinous cost implications from end-of-life treatments that they do in the US' complex and expensive system. "But Hong Kong is increasingly getting the issue of high [health care] costs because of its ageing population," says Dr Lam Tung. The physician runs the Awakening Research Foundation, which gives end-of-life counselling to terminal patients.
"Advance directives help people make health care decisions for themselves; it takes stress away from their families. And they're good for the health care industry because they can cut costs."
Dr Tse Chun-yan, chairman of the Hong Kong Hospital Authority's clinical ethics committee, says the issue goes far beyond costs.
"This has developed mainly because of the rapid advances in medical technology. We're good at keeping people alive, but we have to think about the implications when this is applied to terminally ill people - we have to stop and think whether it's worth it.
"The concept and ethical principle that support advance directives aren't financial, even in the US. The principle is patient autonomy. Some treatments are really just prolonging the time taken to die; this way, patients can make their own choice about them."
Lam's experiences show just how rare advance directives remain in Hong Kong. He set up the Awakening foundation in 2012 but has held fewer than 10 consultations so far.
"Not that many Hong Kong people are familiar with the concept," he says. He surveyed nearly 1,000 people in 2012, and 99.3 per cent had never heard of them.
Nonetheless, they have been discussed for a while at government level. Guidelines issued by the Hospital Authority in 2002 regarding the use of life-sustaining treatment on terminally ill people contained a small section on advance directives, taken from guidelines previously issued by the British Medical Association.
Then, in 2006, Hong Kong's Law Reform Commission published a report on the subject, and in 2009 the Food and Health Bureau published a consultation paper based on the report, which discussed the idea of introducing them.
Among the more complex issues is the legal framework governing their use. Hong Kong is a common-law jurisdiction and, therefore, precedent can be as important as statute. But when the Medical Council of Hong Kong's ethics committee looked into advance directives, it found the whole issue so thorny that it recommended a statutory framework to make it less legally ambiguous. The council says it has reservations about doctors popularising advance directives while there are still so many complicated, unresolved issues surrounding them.
The government said in response that the lack of familiarity with them in Hong Kong meant that it's not yet time to think about a statutory framework.
While respondents to the 2009 paper "generally were not against introducing the concept of advance directives as a personal decision, there was not yet any consensus nor public support for promoting this by way of legislation", says a spokeswoman from the Food and Health Bureau.
The government acknowledges that the main issue is making people aware of advance directives, and says that it wants to do so, but is reluctant to actively advocate that people set up advance directives, since it's a personal decision.
Nonetheless, the Hospital Authority has issued guidelines to clinical staff, with a particular focus on clinical units such as palliative care and oncology, and provided training to staff about introducing patients to the notion of advance directives.
The Food and Health Bureau spokeswoman says that these days "there appears to be more receptiveness from patients and their families toward the information provided by the Hospital Authority regarding the concept of advance directives, [but] we have yet to see a substantial change in attitude in the community at large towards promoting advance directives through legal means".
The Hospital Authority has also put a sample form on its website, albeit intended as a guide rather than a tool for writing an advance directive. It focuses on specific treatments rather than desired outcomes.
"An expression of values and preferences is very useful, but it's not the focus of the advance directive model we're using," says Tse. "It's better to discuss specifics: for instance, if someone suffers from cardiac arrest, whether CPR should be used. The advance care planning process can have many outcomes, and it might not end with someone signing an advance directive."
Cultural factors can come into play; the Chinese tradition of patients' families making end-of-life decisions for them could prove a hurdle.
But a 2011 study by Dr Chu Leung-wing of Hong Kong University's medical faculty suggests that older people might not be so resistant to the idea if they're given all the information. Of 1,600 Chinese people with an average age of 82.4 years interviewed in nursing homes who were informed about advance directives, 88 per cent said they'd like one.
Cultural issues are a hindrance up to a point, says Tse: "From the experience of palliative care workers, most people facing death are prepared to discuss it, even if they're very traditional.
"There just isn't much of an obstacle when they're near the end of life," Tse says.
Seek medical advice before signing
The business of compiling an advance directive is not to be taken lightly. Decisions should involve the patient, their health care team and their family.
A good place to start is the form available on the Hong Kong Hospital Authority website ha.org.hk/visitor/ha_index.asp There are many other sample forms on the internet, most of them primarily intended for use in the US, such as MyDirectives mydirectives.com/
Taking medical advice is critical. Most of us don't understand the complicated specifics of potential end-of-life treatments, and certain terms are open to interpretation.
"They need to explain the meaning of 'life-sustaining treatment'," says Dr Lam Tung. "At the end of life, it can mean anything that keeps people alive: medication, feeding, hydration. It depends on the individual's decision - what they want to go through and what they don't."
The boundaries of what a patient can decide touch on medical ethics. "Intravenous fluid is a life-sustaining treatment, but some doctors think it's a basic human right," says Lam. "So if the patient doesn't specifically mention not to, they'll still give it."
One additional problem in Hong Kong is that people in a coma or a persistent vegetative state are not classified as "mentally incapacitated"; without enduring power of attorney, it's difficult to know who's responsible for managing their affairs.
Under those circumstances, an advance directive can be a very valuable document.