Background: The clinical utility of measures of dyspnea has been debated in the health care community. Although breathlessness can be evaluated with various instruments, the most effective dyspnea measurement tool for patients with chronic lung disease or for measuring treatment effectiveness remains uncertain. Understanding the evidence for the validity and reliability of these instruments may provide a basis for appropriate clinical application.
Objective: Evaluate instruments designed to measure breathlessness, either as single-symptom or multidimensional instruments, based on psychometrics foundations such as validity, reliability, and discriminative and evaluative properties. Classification of each dyspnea measurement instrument will recommend clinical application in terms of exercise, benchmarking patients, activities of daily living, patient outcomes, clinical trials, and responsiveness to treatment.
Methods: Eleven dyspnea measurement instruments were selected. Each instrument was assessed as discriminative or evaluative and then analyzed as to its psychometric properties and purpose of design.
Results: Descriptive data from all studies were described according to their primary patient application (ie, chronic obstructive pulmonary disease, asthma, or other patient populations). The Borg Scale and the Visual Analogue Scale are applicable to exertion and thus can be applied to any cardiopulmonary patient to determine dyspnea. All other measures were determined appropriate for chronic obstructive pulmonary disease, whereas the Shortness of Breath Questionnaire can be applied to cystic fibrosis and lung transplant patients. The most appropriate utility for all instruments was measuring the effects on activities of daily living and for benchmarking patient progress. Instruments that quantify function and health-related quality of life have great utility for documenting outcomes but may be limited as to documenting treatment responsiveness in terms of clinically important changes.
Conclusions: The dyspnea measurement instruments we studied meet important standards of validity and reliability. Discriminative measures have limited clinical utility and, when used for populations or conditions for which they are not designed or validated, the data collected may not be clinically relevant. Evaluative measures have greater clinical utility and can be applied for outcome purposes. Measures should be applied to the populations and conditions for which they were designed. The relationship between clinical therapies and the measurement of dyspnea as an outcome can develop as respiratory therapists become more comfortable with implementing dyspnea measurement instruments and use the data to improve patient treatment. Dyspnea evaluation should be considered for all clinical practice guidelines and care pathways.