Validity of a self-administered questionnaire version of the Transition Dyspnea Index in patients with COPD

Background: The transition dyspnea index (TDI) is one of the most widely used instruments in patients with COPD to measure changes in subjectively perceived dyspnea over time. In its original version it is used as guideline for a structured interview to assess the impact of daily activities on dyspnea in the three subdomains of functional impairment, magnitude of task, and magnitude of effort. These dimensions are further condensed into a summary score. However, the TDI is often used as a self-administered paper-and-pencil questionnaire. To our knowledge, the validity of this questionnaire format has not been es…