Monitoring the quality of life in patients with coronary artery disease

Monitoring the outcomes of treatment and quantifying patients' functional status have assumed a prominent role in both clinical trials and quality assurance programs. Because patients with coronary artery disease (CAD) may have comorbid illnesses, and because generic health status questionnaires may not focus on symptoms and impairments unique to coronary disease, a generic measure of health status may not be sufficient to detect important changes in patients' CAD. The responsiveness to clinical change of the Seattle Angina Questionnaire (SAQ), a disease-specific measure for CAD, was compared with that of the Short Form-36, a generic measure of health status. Both questionnaires were serially administered, 3 months apart, to 45 patients undergoing coronary angioplasty and to 130 patients with stable CAD. Most scales of both questionnaires improved significantly after coronary angioplasty. The responsiveness statistics of the SAQ exceeded those of the Short Form-36. Among 130 patients with initially stable angina, 33 deteriorated, 79 remained stable, and 18 improved over 3 months of observation. Mean SAQ scores changed significantly and appropriately in each of these groups. In contrast, none of the Short Form-36 scales detected these more subtle changes. Although useful in assessing overall function, a generic health status measure, such as the Short Form-36, may not be responsive enough to detect important clinical changes in patients' CAD. A disease-specific instrument, such as the SAQ, can be an important and relevant outcome measure in clinical trials or quality assurance programs.