Assessment of functional status in patients with cardiac disease.

The evaluation of functional status as an outcome for patients with cardiac disease has become common practice in both clinical settings and research studies. However, the measurement of functional status lacks conceptual clarity, frequently focuses on only one dimension of functioning, and overlooks the individuality of the patient. Some measures of functional status have questionable sensitivity to capture change over time, or the ability to discriminate between groups, and lack reports of reliability and validity testing. The purpose of this article is to discuss critical issues related to the evaluation of functional status, with a focus on objective and subjective measures of functional status frequently used in cardiac populations.