[Quality of life in medicine. Introduction of the concept in clinical-epidemiological research and health care planning].

The article summarizes current issues and future directions in Quality-of-Life (QoL) investigation. The concept of QoL aims to provide an accurate evaluation of how a disease and its related treatments impact upon patient's physical, psychological and social well-being. Moreover, QoL indices have been employed as an outcome variable in randomized controlled trials and in the economic analysis of treatments. Though researchers are still debating what should be included in QoL assessment and how investigations should be carried out, relevant contributions were provided, particularly in the fields of oncology and cardiovascular diseases. The need of meaningful data on patient's QoL calls upon a more rigorous methodological framework and the availability of psychometrically sound questionnaires that are appropriate to the population, setting, and goals of investigation.