Quality of life

Owing to the considerable progress made over the past few decades in the surgical and interventional treatment of congenital heart defects, about 90% of patients now reach adulthood. There is thus a rising generation of young adults with chronic heart problems who need lifelong medical care. As a result of the good survival rate of patients with congenital heart defects, treatment nowadays has a strong focus on functional aspects, such as cardiac function, heart rhythm, or physical strength and endurance, and their long-term progression. Since the ultimate aim of treatment must necessarily be to improve the quality of patients’ lives, quality of life will take on increasing importance as the measure of success for any particular form of therapeutic treatment.

Consequently, quality-of-life measurements ought to be included in all studies (not only those conducted by the competence network), and be taken as a main criterion when assessing the results of therapeutic measures. Performing comparisons of clinical functional data with an assessment of subjectively and objectively perceived quality of life will not only help to broaden our scientific knowledge but also, one day, enable us to improve patient-oriented healthcare options.

Quality of life is a multidimensional concept in which separate dimensions are weighted differently by different individuals. One person might lay more emphasis on physical strength and endurance, while another person might rate their social situation more highly.

Quality of life is always purely subjective. Objective measurements of factors affecting quality of life, such as physical strength and endurance, social environment, financial situation, or cognitive ability, will always be no more than determining factors – and must never be confused with the real quality of life itself, which is intrinsically subjective.

Finally, quality of life also depends on a subject’s personal expectations, producing an equation in which quality of life is defined as the difference between expectation and actual experience.

These days, the internationally accepted, general definition of quality of life is “satisfaction with life“.

The more general the questions used to determine quality of life, and hence the more personal the answers, the longer it takes to analyse the results, the greater the variance in a group of test subjects and the less statistically significant the changes in small groups of subjects when investigating a narrowly defined issue. A distinction is therefore made between instruments designed to gather detailed data on quality of life and extensive psychological tests. The latter, however, are rarely employed outside of large population studies, where they are used to account for cultural differences. There are generic questionnaires with a strong bias on health issues, used to compare the quality of life of patients suffering from different diseases. These deal mainly with the effect of state of health/illness on quality of life. There are also more specialised questionnaires used to determine quality of life in patients with one specific disease. But closer examination of these questionnaires reveals that they only ask the subjects to describe their subjective feelings in relation to a list of symptoms of the disease, and do not address quality of life as such, in the way that it is defined above. Therefore, they are often addressed as “health status”.

All studies carried out by the competence network include gathering data on quality of life using generic questionnaires to obtain subjective viewpoints on health-related quality of life. The subjects are interviewed on their health-related quality of life prior to and at 12 months after therapeutic treatment. Adults are interviewed using the SF-36 survey (New England Hospital Inc.) on their perceived physical, social and emotional health. Children in the 4-16-year age group are asked to comment on their physical and mental well-being using the KINDL questionnaire (Ravens-Sieberer & Bullinger), and to express their interactive role in family and society. For very young children, a neutral interviewer (not the parents) conducts the questioning.

When evaluating the data, particular attention is paid to the correlation between the measured scores typically obtained through “technocratic medicine” and the impairments to quality of life reported by the patients.

Further information on the KINDL questionnaires and downloads can be found at www.kindl.org