Measurement of the quality of life in congestive heart failure--influence of drug therapy.

In cardiovascular diseases such as hypertension, drug therapy may improve survival and the drug of choice is the one that interferes least with health-related well-being, otherwise known as the quality of life. However, in angina, and possibly congestive heart failure, a drug may improve well-being but not survival. In this instance, the measurement of the quality of life is the endpoint in any therapeutic intervention. When selecting dimensions of quality of life and the methods to measure these dimensions, the key issue is the detection of a response to treatment during the trial. The sensitivity of a variety of methods appropriate to hypertension, angina, and congestive heart failure are considered. Overall, the quality of life should be assessed by double-blind, randomized, controlled trials, with a health index included to take account of any mortality and morbidity that occurs during the trial. Validity and repeatability of measures are most important, both within populations and across cultures. Observer bias must be avoided.