Quality-of-Life Assessments in Clinical Trials

Less than 10 years ago the scientific community believed that quality of life (QOL) was part of the art of medicine rather than the science of medicine. In the past few years index methods have been developed and have proven to be sensitive and specific to assess patients' health status not only on a physical, but also on a psychological and social base. We increasingly witness that QOL is implemented in the scientific evaluation of medicine. However, major problems with QOL assessments so far, include the contributing factor patients- opinion, which is very subjective and, therefore, scientifically difficult to handle, and, second, the low sensitivity of QOL-questionnaires to reflect true changes in QOL. The Dutch Mononitrate Quality Of Life (DUMQOL) Study Group has recently addressed both problems. In their hands, the patients' opinion was a consistent and statistically independent determinant of QOL in patients with angina pectoris. The problem of low sensitivity of QOL-assessments could be improved by replacing the absolute score-scales with relative ones, using for that purpose odds ratios of scores. The current chapter reviews the main results of this so far only partly published research 1,2 from the Netherlands.