How do we measure “Quality of Life”?

06 Dec 2011By Dr Wong Ting Hway, Singapore

We often use “quality of life” to explain medical decision-making, especially at the end of life. The more medical technology progresses, the more we realise that it is not just the length, but the quality of survival, that matters.

Expectations of life

That said, there are patients with severe disease who report a reasonable quality of life. One explanation is that quality of life is the discrepancy between our expectations of life and our experience of it. Patients who have low expectations or who have become accustomed to their reduced level of function may regard their quality of life as good. On the other end of the spectrum, patients with good function and high expectations may rate a minor disability as a severe reduction in quality of life (the “disability paradox”).

Hence the importance of patient peer-support groups in many chronic disease conditions: meeting someone else (amputee, arthritis, alcoholism, etc) with similar experiences (or with worse disability but coping well) puts your own expectations in context.

All these factors make it difficult to measure quality of life: people have different personalities and expectations at the beginning of their illness, people may be at different phases of their illness when their quality of life is measured, and their expectations may change over time (the “response shift”).

Dr Death

My mother used to support people who facilitated euthanasia, like the late “Dr Death”. As soon as it became available in Singapore, she signed an Advanced Medical Directive. When friends or relatives passed away, she consoled herself: “they are happier now and no longer suffering”.

Last year she was diagnosed with a progressive terminal illness. She began to talk about euthanasia for herself and how she wanted to end things while “the going was good and she was still able to get going”.

She weakened slowly over the months. She talked less about euthanasia, at least with regard to her own situation. Her attitude, however, appeared unchanged – in many of her hospitalisation episodes, she would point to someone else in the same ward and say out loud: “she shouldn’t be kept alive – she’s suffering”. (Much to our horror and embarrassment, she often said this within earshot of the family of whoever she was pointing to.)

Why measuring quality of life is important

Given how subjective quality of life is, why do doctors still look for the “perfect” measuring tool, especially in chronic disease and end-of-life situations?

In clinical practice, quality of life tools can help identify and prioritise complex problems the patient is facing. It can help communication when the patient has multiple symptoms, screen for hidden problems, and assist in shared clinical decision making.

More commonly, it helps monitor response to treatment. In cancer, for example, where some of the treatments have side effects that affect patients’ function, but can prolong the number of days, quality of life measures are used.

As a research tool, quality of life measures can compare two different treatments for the same disease or symptom where outcome measures are not clear. A simplified example would be: comparing one treatment which prolongs life by 2 months but has severe side effects, with another treatment that prolongs life by 1 month with minor side effects.

What happens when the patient cannot communicate their wishes? In such situations, we often expect their partners or close family to act as their proxies – people who know what the patient would want in a similar situation and who would act in their best interests. How much is the agreement between the patient and their partner, or between the patient and their healthcare worker? – Studies have shown fairly good agreements (almost half were identical or close ratings, and less than 20% showed profound discrepancies).

But is that enough? Unfortunately, as in the story mentioned in the beginning of the article, not everyone accepts this assumption. We can ask as many people as we can what they would wish in the same situation, but they are not that person. Even if you are that person, things may change over time.


My mother’s disease continued to progress. A few times, she was admitted to the intensive care unit. Each time, she would initially refuse intubation, and we would talk her into accepting it.

She recovered well each time – somehow proving that we (her “proxies”) had been right to “persuade” her into accepting life-support measures.

I left for a brief period of training in Australia when her disease looked stable. She was suffering from a bad bout of oral thrush infection when I left, and our farewell dinner was quite disappointing – her favourite curry dish “only tasted of pain” and she stared at the food on the table mumbling, “What a waste…”

When peach season arrived in Australia, I lamented to myself that I could not bring the peaches back home for my mum, who loves peaches.

Midway through my training, I received a phone call. My mother was in intensive care again. I booked my flight back. On the way out of the house, I grabbed a bag of peaches from the kitchen.

I stayed in Singapore long enough to see my mother out of intensive care and extubated. She devoured the peaches. I took her out on home leave while in hospital, back to her favourite restaurant. Her oral thrush infection had been treated and she wolfed down her food.

Her memory is fading, and she now needs to be in a wheelchair when she goes out. She used to be imperiously impatient and pride herself in being the fastest to do anything – one of her favourite phrases was “time and tide and Irene wait for no man, woman or child”. Now, whenever we tell her it is time to do something – go out with us, take a shower, change her clothes… she would refuse to let us help her (not even with the simplest task of getting dressed), scold us for not giving her time to think, then stop and stare around her, looking for something she would never find.

I don’t know what she would have thought of herself last year, had she seen herself now.

Yet, she has stopped talking about ending her life, and seems to be enjoying it.

Dr Wong Ting Hway is an Associate Consultant in the Department of General Surgery of Singapore General Hospital.

This photograph, courtesy of Dr Wong, was taken at her graduation from Cambridge University in 1992, with sister, and mother, Dr Irene Giam, PhD (right). This story first appeared in the September/October 2011 issue of Salubris, a newsletter of National Cancer Centre Singapore, as “Quality of Life – A personal and professional perspective”. The article is republished here with permission.

Dr Wong’s mother suffers from vascular dementia due to a progressive terminal illness. They are featured in the Before We Forget documentary. In May, Dr Wong contributed “Rewriting the obituary” to Before We Forget.