[Considerations on the use of the construct "Quality of life" as a goal variable in clinical research]

In recent years the importance of the assessment of quality of life increased, especially in palliative therapy. Commonly used concepts of quality of life comprise of several dimensions, e.g. somatic disorders, functional status, well-being and social interaction. We developed an 18-item questionnaire, self-administered by the patients, and compared the results of 66 'healthy' subjects with two clinical samples: 126 patients with inoperable non-small-cell lung cancer and 19 patients under dialysis. The results indicate the questionnaire as a sufficiently reliable and valid method for the assessment of 'quality of life'. On the other hand, there are several problems concerning an adequate interpretation when regarding our clinical data. For example, the cancer patients show a significantly more positive self-assessment concerning well-being and activity, compared to 'healthy' subjects.