Measuring the quality of well-being in cystic fibrosis and lung transplantation. The importance of the area under the curve.

The quality of well-being scale (QWB) has been used to measure overall life quality in a number of different clinical conditions, including cystic fibrosis and chronic obstructive pulmonary disease. Evidence supports its validity and reliability in both cross-sectional and longitudinal studies. One of the strengths of the QWB is that it is not organ-specific, so that it can take into account the broad impact of a disease and/or intervention, including unanticipated effects. The well-year of life is a concept that includes both morbidity and mortality: if a disease reduces quality of life by one-half, over a period of two years, that person can be said to have lost one full well-year. As we examine the impact of diseases such as cystic fibrosis, and of interventions such as lung transplantation, it is important to consider changes in overall well-being over time to help individual patients and families make difficult therapeutic choices and to help formulate health policy.