Relation of clinical and angiographic factors to functional capacity as measured by the Duke Activity Status Index

Improvement of patient functional status is an important goal in the therapy of cardiovascular disease. Given the pressures on the medical profession to restrain the growth of health care costs, credible documentation of improved functional capacity as a result of therapy is particularly important, especially if effects on “hard end points” such as death or myocardial infarction are difficult to demonstrate. Measurement of functional status inevitably includes a subjective component, so that most physicians consider it a “soft end point.” Indeed, traditional measures, such as the New York Heart Association classification, have considerable imprecision and interobserver variability. In an attempt to overcome some of these limitations, we recently described a new method of determining functional capacity of patients with cardiac disease. 1 The Duke Activity Status Index (DASI) is a brief self-administered questionnaire that gauges the patient's ability to perform common activities and uses the responses in a weighted score that assesses overall patient functional capacity. To determine if DASI varies in an appropriate fashion according to clinical factors known to influence patient functional status, this study examines the correlation of DASI with clinical factors in a large, independent group of patients.