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      Measuring respiratory symptoms of COPD: performance of the EXACT- Respiratory Symptoms Tool (E-RS) in three clinical trials

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          Symptomatic relief is an important treatment goal for patients with COPD. To date, no diary for evaluating respiratory symptoms in clinical trials has been developed and scientifically-validated according to FDA and EMA guidelines. The EXACT – Respiratory Symptoms (E-RS) scale is a patient-reported outcome (PRO) measure designed to address this need. The E-RS utilizes 11 respiratory symptom items from the existing and validated 14-item EXACT, which measures symptoms of exacerbation. The E-RS total score quantifies respiratory symptom severity, and 3 domains assess breathlessness, cough and sputum, and chest symptoms.


          This study examined the performance of the E-RS in each of 3 controlled trials with common and unique validation variables: one 6-month (N = 235, US) and two 3-month (N = 749; N = 597; international). Subjects completed the E-RS as part of a daily eDiary. Tests of reliability, validity, and responsiveness were conducted in each dataset.


          In each study, RS-Total score was internally consistent (Cronbach α) (0.88, 0.92, 0.92) and reproducible (intra-class correlation) in stable patients (2 days apart: 0.91; 7 days apart: 0.71, 0.74). RS-Total scores correlated significantly with the following criterion variables (Spearman’s rho; p < 0.01, all comparisons listed here): FEV 1% predicted (−0.19, −0.14, −0.15); St. George’s Respiratory Questionnaire (SGRQ) (0.65, 0.52, 0.51); Breathlessness, Cough, and Sputum Scale (BCSS) (0.89, 0.89); modified Medical Research Council dyspnoea scale (mMRC) (0.40); rescue medication use (0.43, 0.42); Functional Performance Inventory Short-Form (FPI-SF) (0.43); 6-minute walk distance (6-MWT) (−0.30, −0.14) and incremental shuttle walk (ISWT) (−0.18) tests. Correlations between these variables and RS-Breathlessness, RS-Cough and Sputum, RS-Chest Symptoms scores supported subscale validity. RS-Total, RS-Breathlessness, and RS-Chest Symptoms differentiated mMRC levels of breathlessness severity (p < 0.0001). RS-Total and domain scores differentiated subjects with no rescue medication use and 3 or more puffs (p < 0.0001). Sensitivity to changes in health status (SGRQ), symptoms (BCSS), and exercise capacity (6MWT, ISWT) were also shown and responder definitions using criterion- and distribution-based methods are proposed.


          Results suggest the E-RS is a reliable, valid, and responsive measure of respiratory symptoms of COPD suitable for use in natural history studies and clinical trials.

          Trial registration

          MPEX: NCT00739648; AZ1: NCT00949975; AZ 2: NCT01023516

          Electronic supplementary material

          The online version of this article (doi:10.1186/s12931-014-0124-z) contains supplementary material, which is available to authorized users.

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          Most cited references 35

          • Record: found
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          Standards for the diagnosis and treatment of patients with COPD: a summary of the ATS/ERS position paper.

           W MacNee,  ,  B Celli (2004)
            • Record: found
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            • Article: not found

            St. George's Respiratory Questionnaire: MCID.

            The SGRQ is a disease-specific measure of health status for use in COPD. A number of methods have been used for estimating its minimum clinically important difference (MCID). These include both expert and patient preference-based estimates. Anchor-based methods have also been used. The calculated MCID from those studies was consistently around 4 units, regardless of assessment method. By contrast, the MCID calculated using distribution-based methods varied across studies and permitted no consistent estimate. All measurements of clinical significance contain sample and measurement error. They also require value judgements, if not about the calculation of the MCID itself then about the anchors used to estimate it. Under these circumstances, greater weight should be placed upon the overall body of evidence for an MCID, rather than one single method. For that reason, estimates of MCID should be used as indicative values. Methods of analysing clinical trial results should reflect this, and use appropriate statistical tests for comparison with the MCID. Treatments for COPD that produced an improvement in SGRQ of the order of 4 units in clinical trials have subsequently found wide acceptance once in clinical practice, so it seems reasonable to expect any new treatment proposed for COPD to produce an advantage over placebo that is not significantly inferior to a 4-unit difference.
              • Record: found
              • Abstract: not found
              • Article: not found

              The significance of respiratory symptoms and the diagnosis of chronic bronchitis in a working population.


                Author and article information

                Respir Res
                Respiratory Research
                BioMed Central (London )
                7 October 2014
                7 October 2014
                : 15
                : 1
                [ ]Evidera, 7101 Wisconsin Ave, Suite 1400, Bethesda, MD 20814 USA
                [ ]Formerly Boehringer Ingelheim GmbH, Ingelheim, Germany
                [ ]Merck, Sharp & Dohme, Corp, Whitehouse Station, NJ USA
                [ ]AstraZeneca, Wilmington, DE USA
                [ ]St. George’s, University of London, London, UK
                [ ]University of Buffalo, Buffalo, NY USA
                © Leidy et al.; licensee BioMed Central Ltd. 2014

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

                Custom metadata
                © The Author(s) 2014

                Respiratory medicine

                respiratory symptoms, copd, clinical trials, dyspnoea, cough, sputum, chest symptoms


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