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

Table 5 E-RS Responder estimates using distribution-based methods by trial: ½ SD and SEM ^*

Scale Method^†	Mpex	AZ 1	AZ 2
Scale Method^†	(N = 235)	(N = 749)	(N = 597)
RS-Total
½ SD	2.97	3.00	2.995
SEM	1.88	1.47	1.34
RS-Breathlessness
½ SD	2.97	1.59	1.56
SEM	1.57	0.78	0.76
RS-Cough and Sputum
½ SD	1.04	0.78	0.80
SEM	1.44	0.81	0.75
RS-Chest Symptoms
½ SD	1.04	0.97	0.96
SEM	0.42	0.47	0.51

* $S E M = S D \sqrt{1 - α}$ .
^†Weekly scores at baseline, Day -7 to Day 1; Ranges: RS-Total: 0 to 40; RS-Breathlessness: 0 to 17; RS-Cough and Sputum: 0 to 11; RS-Chest Symptoms: 0 to 12; higher scores = more severe symptoms.
Abbreviations: AZ AstraZeneca, E-RS Exacerbations of Chronic Pulmonary Disease Tool – Respiratory Symptoms, SD standard deviation, SEM standard error of measurement.

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