Functional Tests in Chronic Obstructive Pulmonary Disease, Part 2: Measurement Properties
Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and an important cause of disability and handicap. For a thorough patient-centered outcome assessment and comprehensive management of the disease, measures of lung function, exercise capacity, and health-related quality of life, but also of functional capacity in activities of daily life, are necessary. In Part 2 of this seminar series, we discuss the main functional tests to assess upper and lower body functional capacity in patients with COPD to help clinicians substantiate their choice of functional outcome measures in COPD. In agreement with the International Classification of Functioning, Disability and Health to assess functional capacity representative of daily life activities, this review focuses on functional tests that include components such as changing and maintaining body positions, walking, moving, and climbing, as well as carrying, moving, and handling objects. We review the validity, reliability, and responsiveness of these tests. With 11 links to the International Classification of Functioning, Disability and Health framework addressing several upper and lower body components of functional activities, the Glittre Activities of Daily Life test seems to be the most promising and comprehensive test to evaluate functional capacity in activities of daily life. The links between functional capacity tests and real participation in daily life, as well as with important clinical outcomes such as morbidity and mortality, need further investigation. More studies are also recommended to document minimal detectable changes, minimal clinically important differences, and normative values for these functional tests.