Outcome measurement of refractory breathlessness: endpoints and important differences.

Abstract

Standardized measurement of self-rated breathlessness using appropriate tools is essential for research and clinical care. The purpose was to review recent advances in the measurement of breathlessness and the minimal clinically important differences (MCIDs) in intensity of chronic breathlessness. Two tools have been validated in people with chronic obstructive pulmonary disease (COPD) to measure daily symptoms and breathlessness related to daily activities. Two multidimensional tools have been developed for different settings and aetiologies, which measure both the perceived intensity, unpleasantness, quality of breathlessness, and the person's emotional response to it. MCIDs have been reported for the intensity of chronic refractory breathlessness, the daily symptom diary, and breathlessness related to daily activities in COPD. There have been substantial developments in instruments able to provide reliable and valid unidimensional and multidimensional measurement of self-reported breathlessness and in the understanding of the MCID for chronic breathlessness. Routine use of agreed outcome measures in clinical practice and research are crucial steps to improve our understanding of the science of breathlessness and its impact on patients' outcomes.