Interview with Philip Moons about quality of life

(© University of Leuven)

In this interview, the Belgian scientist Philip Moons talk about his approach to the term quality of life and why adults with congenital heart diseases tend to have a better quality of life than the average population does. He has written many scientific articles about both congenital heart diseases and quality of life.

What is the best way to measure quality of life?

I don’t have the answer to that. It is a complex issue. Researchers do not agree on a conceptualisation of quality of life, meaning that we have different ways to approach the term. The method depends on your approach, so to speak. A person who defines quality of life as “health status” will use an instrument that reflects this definition.

What is your approach?

We know that a relationship between health status and quality of life exists, but the two are not the same thing. Happiness is another approach. We know that there is a relationship between happiness and quality of life, but happiness is a short-term feeling that can change within a minute. Quality of life is also changeable, of course, but is still far more stable than happiness is. In my opinion, satisfaction with life is the best approach for measuring quality of life, because it includes so many aspects. If you ask individuals to think about their satisfaction with life, you make them consider the life that they have been living so far and they can give an overall appreciation of life.

SEIQoL-DW (Schedule for the Evaluation of Individual Quality of Life – Direct Weighting) is an instrument that has been developed to measure individual quality of life. The use of SEIQoL-DW overcomes the problem of predetermined questions, which assume that each person’s quality of life is affected by the same determinants. You were the first person to use SEIQoL-DW for patients with congenital heart diseases. How did it work out?

It worked very well! In addition to SEIQoL-DW we used different instruments that also had predefined questions. The individual approach gave us more details, which we could not obtain with predefined questionnaires. For example, if a patient says that her dog is the utmost important thing to her, this answer will not be included in a predefined questionnaire. I have never seen such an instrument that has included pets.

Instruments measuring quality of life are mainly divided in two groups: predefined questionnaires and individually-oriented forms such as SEIQoL-DW. What is the problem with predefined questionnaires?

Are we measuring quality of life itself or factors that are important for it? If you can walk three blocks, is that a measure of quality of life or of functional status? Having friends and a good network, is that a sign of quality of life or determinants of quality of life? Measuring this term with predefined questions can be very brief, with only a few items on the questionnaire. When we need more in-depth information, I prefer to use SEIQoL.

How do you measure quality of life with children?

I have been involved with many studies with children. One of my co-workers started a project, but realised that it was not about quality of life, but of related aspects. Thus, the project used the term health status instead. To measure quality of life with children is difficult, if not impossible. Answering questions regarding quality of life needs a certain amount of abstract thinking that children simply do not have. Of course, the parents know their children well and can give expressions and answers on their behalf. But that is not the same as the children answering for themselves, and mostly these answers tell us more about the quality of life for the parents.

So your research cannot be transferred to children?

I do not think so. Some aspects might be similar, such as learning to integrate a sickness into your life. However, this aspect seems to be more difficult for parents than for children.

What are the most important factors for measuring a persons´ quality of life?

Our studies show that 80% of respondents put family as the number one on their priority list. The rest of the top-five list is job/education, friends, health and leisure time. As you can see, health is number four on the list. 60% of respondents put that on the priority list, indicating that 40% do not consider health as a major issue. That explains why the term health-related quality of life is not always suitable, since it over emphasises the meaning of health.

What is the best definition of quality of life?

There are a lot of definitions! It depends on the conceptual approach from the scientist. If you define quality of life as health status, your definition will express this belief. I define it as satisfaction with life, and have developed a definition that expresses this. I cannot say that my definition is best or the only one. It is a subject for debate.

And your definition is …

The degree of overall life satisfaction that is positively or negatively affected by people’s perception of specific aspects of life important to them, including matters both related and unrelated to health.

Is it a problem that scientists do not agree on the definition?

I do not think that the scientific community will ever agree. Is it important that scientists agree on all aspects? Some measures do need consensus. For example, if my meter is different from your meter, we obviously cannot communicate because it will be impossible to compare data. We have to agree that we disagree on the definition. But most importantly, we have to specify what we mean by the term quality of life.

What can you say about the importance of children being overprotected and having restrictions placed on them?

It has an effect, but our quality-of-life research cannot conclude to what extend. In in-depth interviews, adult patients with congenital heart diseases have talked about what it was like growing up. Patients that were overprotected in childhood and who denied their heart defect were confronted with it at a later age. Patients who were made to face their heart defect at early age and who, for example, had to mow the lawn like their brother, but at their own speed, learned to cope with their disease better than other patients did, and their disease was more successfully integrated into their daily life.

Do academic skills affect quality of life?

Yes indeed. Actually, we have very recent information about this relationship that has not yet been published. We divided the patients in our study into three groups: those with good, moderate and poor quality of life. Then we looked for differences between the groups. We noted that educational level differed in the three groups. The group with good quality of life had a higher degree of education on average than did the group with poor quality of life.

Do adult patients with congenital heart disease who study or work have a better quality of life than those who are unable to work or are unemployed?

Indeed. In the same study as I mentioned earlier, we looked for a relationship between quality of life and employment status. People who work, irrespective of the type of work they do, are more likely to have better quality of life than are those who are unemployed.

How does an invisible handicap affect quality of life?

I believe that other aspects are more important than this factor. A Canadian group has worked on what we call “the disability paradox”, and were amazed to find that patients with poor health status reported good quality of life. They identified factors contributing to good or poor quality of life. The main factor contributing to good quality of life was the ability to preserve control over body, mind and life. They felt satisfied with comparing themselves with others in similar situation. Having pain, suffering from frequent fatigue and loosing control over body functions were rated the worst in terms of quality of life. These are factors that seldom occur for patients with congenital heart disease.

Do patients with congenital heart diseases tend to be more mature or reflective than other people their age?

As yet, we have no data for this. By using the “sense of coherence” approach, we are able to examine the way that they look at their life. We have a hypothesis about why adult patients have a better quality of life than the average population does: they know what life is about! I hope to be able to examine this notion in the future. But it will at least take another 15 years for the hypothesis to be confirmed!

Your research does not include people with learning disabilities, etc. What do we know about their quality of life?

Hardly anything. We have excluded this group for the same reason as we do children. Measuring quality of life needs a certain amount of abstract thinking. However, we are fortunate that this group is not very large.

Do adults with congenital heart disease have a better quality of life than you expected?

I did not expect it to be worse than the healthier population. We found that it was better! Perhaps this finding can be explained by their maturity or the disability paradox. Adults with congenital heart defects have learned to cope with their disease!