Evaluation of quality of life in clinical trials of cardiovascular disease.

There is an increasing interest in the use of quality of life methods to assess the benefits of treatment in cardiovascular disease. When selecting dimensions of quality of life and the instruments to measure these dimensions, the key issue is the detection of a response to treatment during the trial. The sensitivity of a variety of instruments appropriate to hypertension, angina and congestive heart failure is reviewed. Quality of life should be assessed in double blind randomized controlled trials. A Health Index must be included to take into account any mortality and morbidity occurring during the trial. Data are presented on the measurement of quality of life in patients taking placebo prior to entering trials of antihypertensive treatment. The variation with age, sex and nationality is discussed. Also reported are the results arising from observer bias in a single-blind trial.