Quantification of dyspnoea using descriptors: development and initial testing of the Dyspnoea-12
- 1School of Nursing, Faculty of Health and Social Care, University of Salford, Greater Manchester, UK
- 2National Heart and Lung Institute, Charing Cross Hospital Campus, Imperial College London, UK
- 3Nursing and Clinical Governance, Royal Brompton and Harefield NHS Foundation Trust, UK
- 4Division of Cardiac and Vascular Science, St George’s University of London, UK
- Correspondence to Dr J Yorke, 1.43 Mary Seacole Building, School of Nursing, Faculty of Health & Social Care, University of Salford, Greater Manchester M6 6PU, UK;
- Received 27 April 2009
- Accepted 21 October 2009
- Published Online First 8 December 2009
Rationale: Dyspnoea is a debilitating and distressing symptom that is reflected in different verbal descriptors. Evidence suggests that dyspnoea, like pain perception, consists of sensory quality and affective components. The objective of this study was to develop an instrument that measures overall dyspnoea severity using descriptors that reflect its different aspects.
Methods: 81 dyspnoea descriptors were administered to 123 patients with chronic obstructive pulmonary disease (COPD), 129 with interstitial lung disease and 106 with chronic heart failure. These were reduced to 34 items using hierarchical methods. Rasch analysis informed decisions regarding further item removal and fit to the unidimensional model. Principal component analysis (PCA) explored the underlying structure of the final item set. Validity and reliability of the new instrument were further assessed in a separate group of 53 patients with COPD.
Results: After removal of items with hierarchical methods (n = 47) and items that failed to fit the Rasch model (n = 22), 12 were retained. The “Dyspnoea-12” had good internal reliability (Cronbach’s alpha = 0.9) and fit to the Rasch model (χ2 p = 0.08). Items patterned into two groups called “physical”(n = 7) and “affective”(n = 5). In the separate validation study, Dyspnoea-12 correlated with the Hospital Anxiety and Depression Scale (anxiety r = 0.51; depression r = 0.44, p<0.001, respectively), 6-minute walk distance (r = −0.38, p<0.01) and MRC (Medical Research Council) grade (r = 0.48, p<0.01), and had good stability over time (intraclass correlation coefficient = 0.9, p<0.001).
Conclusion: Dyspnoea-12 fulfills modern psychometric requirements for measurement. It provides a global score of breathlessness severity that incorporates both “physical” and “affective” aspects, and can measure dyspnoea in a variety of diseases.
Funding The questionnaire development study was funded by the Clinical Research Committee Royal Brompton and Harefield NHS Foundation Trust. The Dyspnoea-12 validation study was funded by Action Medical Research.
Competing interests None.
Ethics approval The two studies performed were approved by the local ethics research committees.
Provenance and Peer review Not commissioned; externally peer reviewed.